Consumer medicine information

Donepezil GH

Donepezil hydrochloride

BRAND INFORMATION

Brand name

Donepezil GH

Active ingredient

Donepezil hydrochloride

Schedule

S4

 

Consumer medicine information (CMI) leaflet

Please read this leaflet carefully before you start using Donepezil GH.

What is in this leaflet

This leaflet answers some common questions about Donepezil GH. It does not contain all the available information.

It does not take the place of talking to your doctor or pharmacist.

All medicines have risks and benefits. Your doctor has weighed the risks of you taking Donepezil GH against the benefits they expect it will have for you.

If you have any concerns about taking this medicine, ask your doctor or pharmacist.

Keep this leaflet with the medicine. You may need to read it again.

What Donepezil GH is used for

Donepezil GH is used to treat mild, moderate and severe Alzheimer's disease, also called dementia of the Alzheimer's type.

Donepezil GH will not cure this disease but should help your memory and improve your ability to think more clearly.

This medicine belongs to a group of medicines called acetylcholinesterase inhibitors. They are thought to work by increasing the level of a chemical called acetylcholine in the brain.

Ask your doctor if you have any questions about why this medicine has been prescribed for you. Your doctor may have prescribed it for another reason.

This medicine is not addictive.

This medicine is only available with a doctor's prescription.

Use in Children

Donepezil GH is not recommended for use in children.

The safety and effectiveness of Donepezil GH in children has not been established.

Before you take Donepezil GH

When you must not take it

Do not take Donepezil GH if you have an allergy to:

  • any medicine containing donepezil hydrochloride;
  • piperidine derivatives;
  • any of the ingredients listed at the end of this leaflet.

Some of the symptoms of an allergic reaction may include:

  • shortness of breath;
  • wheezing or difficulty breathing;
  • swelling of the face, lips, tongue or other parts of the body;
  • rash, itching or hives on the skin.

Do not take this medicine after the expiry date printed on the pack or if the packaging is torn or shows signs of tampering. If it has expired or is damaged, return it to your pharmacist for disposal.

If you are not sure whether you should be taking Donepezil GH, talk to your doctor.

Before you start to take it

Tell your doctor if you have allergies to any other medicines, foods, preservatives or dyes.

Tell your doctor if you plan to go to hospital for surgery that requires a general anaesthetic. Donepezil GH may interfere with some of the medicines given during an operation.

Tell your doctor if you have or have had any of the following medical conditions:

  • heart problems (such as irregular or very slow heartbeat, heart failure, myocardial infarction)
  • a heart condition called ‘prolonged QT interval’ or a history of certain abnormal heart rhythms called Torsade de Pointes or if anyone in your family have ‘prolonged QT interval’
  • low levels of magnesium or potassium in your blood,
  • stomach problems, particularly gastric or duodenal ulcer;
  • seizures or fits;
  • asthma or obstructive lung disease;
  • loss of memory or other mental capacity due to stroke or blood vessel problems;
  • tendencies toward aggressive behaviour.

Tell your doctor if you are pregnant or plan to become pregnant or are breast-feeding. Your doctor can discuss with you the risks and benefits involved.

If you have not told your doctor about any of the above, tell them before you start taking Donepezil GH.

Taking other medicines

Tell your doctor if you are taking any other medicines, including:

  • all prescription medicines;
  • all medicines, vitamins, herbal supplements or natural therapies you buy without a prescription from a pharmacy, supermarket, naturopath or health food shop.

Some medicines may be affected by Donepezil GH or may affect how well it works. You may need different amounts of your medicines or you may need to take different medicines. Your doctor will advise you.

Tell your doctor or pharmacist if you are taking any of the following:

  • any other medicine for dementia;
  • medicines used to relieve stomach cramps or spasms, Parkinson's disease or travel sickness;
  • medicines used to treat difficulty in passing urine;
  • medicines used to treat arthritis, pain or inflammation known as non-steroidal anti-inflammatory drugs (NSAIDs);
  • medicines used to relax muscles;
  • medicines used in general anaesthesia
  • medicines used to treat high blood pressure or fast heartbeat;
  • medicines used to treat irregular heart beat such as quinidine;
  • medicines for treating asthma, diarrhoea, depression, schizophrenia and related mental conditions, or used in general anaesthesia;
  • medicines used to treat epilepsy - carbamazepine, phenobarbitone or phenytoin;
  • ketoconazole, a medicine used to treat fungal infections;
  • rifampicin, an antibiotic used to treat tuberculosis;
  • dexamethasone, a corticosteroid medicine.
  • Medicines for bacterial infections eg. clarithromycin, erthyromycin, levofloxacin, moxifloxacin, rifampicin
  • Medicines for heart rhythm problems e.g. amiodarone, sotolol
  • Medicines for depression eg citalopram, escitalopram, amitriptyline, fluoxetine
  • Medicines for psychosis eg pimozide, sertindole, ziprasidone

If you are not sure if you are taking any of these medicines, ask your doctor or pharmacist. Your doctor and pharmacist have more information on medicines to be careful with or avoid while taking this medicine.

How to take Donepezil GH

Follow all directions given to you by your doctor and pharmacist carefully. They may differ from the information contained in this leaflet.

If you do not understand the instructions on the packaging, ask your doctor or pharmacist for help.

How much to take

The usual starting dose for Donepezil GH is one 5 mg tablet each day.

After 1 month, your doctor will assess your response and may increase your dose to one Donepezil GH 10 mg tablet each day.

However, depending on your condition and how you react to the medicine, your doctor may ask you to take a different dose.

How to take it

Swallow the tablets whole with a full glass of water.

When to take it

Take your medicine every night just before you go to bed. Taking it at the same time each day will have the best effect. It will also help you remember when to take it.

Donepezil GH can be taken with or without food.

How long to take it

Continue taking your medicine for as long as your doctor tells you.

This medicine helps to control your condition, but does not cure it. It is important to keep taking your medicine even if you feel well.

It may take several weeks for your medicine to take effect, so do not be discouraged if you do not see an improvement straight away.

If you forget to take it

If you forget to take a tablet, just take one tablet the following day at the usual time then continue as normal.

Do not take a double dose to make up for the dose you missed. This may increase the chance of you getting an unwanted side effect.

If you are not sure what to do, ask your doctor or pharmacist.

If you forget to take your medicine for more than 1 week, call your doctor before taking any more.

If you have trouble remembering to take your medicine, ask your pharmacist for some hints.

If you take too much (overdose)

Immediately telephone your doctor or the Poisons Information Centre (telephone Australia 13 11 26) or go to Accident and Emergency at the nearest hospital, if you think that you or anyone else may have taken too much Donepezil GH.

Do this even if there are no signs of discomfort or poisoning. You may need urgent medical attention.

Symptoms of an overdose may include:

  • feeling sick in the stomach;
  • vomiting;
  • increased sweating or saliva production;
  • slow heart beat;
  • feeling dizzy or faint;
  • difficulty breathing;
  • seizures or fits;
  • feeling weak;
  • unable to control your bowel motions or passing of urine (incontinence).

While you are taking Donepezil GH

Things you must do

If you are about to be started on any new medicine, remind your doctor and pharmacist that you are taking Donepezil GH.

Tell all doctors, dentists and pharmacists who treat you that you are taking this medicine.

If you are going to have surgery, tell the surgeon or anaesthetist that you are taking this medicine. It may affect other medicines used during surgery.

If you become pregnant while taking this medicine, tell your doctor immediately.

Keep all of your doctor's appointments so that your progress can be checked. Your doctor may do some tests from time to time to make sure the medicine is working and to prevent unwanted side effects.

Things you must not do

Do not take this medicine to treat any other complaints unless your doctor says to.

Do not give this medicine to anyone else, even if they have the same condition as you.

Do not stop taking your medicine or change the dosage without checking with your doctor.

Things to be careful of

Be careful driving or operating machinery until you know how Donepezil GH affects you. This medicine may cause fatigue, dizziness and muscle cramps especially at the start of treatment or if the dose is increased. If you have any of these symptoms, do not drive, operate machinery or do anything else that could be dangerous.

In addition, Alzheimer's disease may affect your ability to drive or operate machinery. Ask your doctor whether it is safe for you to continue to drive or operate machinery.

Side effects

Tell your doctor as soon as possible if you do not feel well while you are taking this medicine.

All medicines can have side effects. Sometimes they are serious, most of the time they are not. You may need medical attention if you get some of the side effects.

It can be difficult to tell whether side effects are the result of taking Donepezil GH, the effects of your condition or side effects of other medicines you may be taking. For this reason, it is important to tell your doctor of any change in your condition.

Do not be alarmed by the following list of side effects. You may not experience any of them.

Ask your doctor or pharmacist to answer any questions you may have.

Tell your doctor if...

Tell your doctor or pharmacist if you notice any of the following and they worry you:

  • heartburn, indigestion, or stomach pain;
  • headache or dizziness;
  • difficulty in sleeping;
  • unusual tiredness;
  • feeling sick, diarrhoea, vomiting;
  • loss of appetite, weight loss;
  • bruising;
  • muscle cramps, joint pain;
  • tingling or numbness of the hands or feet;
  • depression, unusual dreams;
  • agitation, aggressive behaviour;
  • difficulty in urinating or passing urine more often.

The above list includes the more common side effects of your medicine. They are usually mild and short-lived.

Tell your doctor as soon as possible if...

Tell your doctor as soon as possible if you notice any of the following:

  • seeing, feeling or hearing things that are not there;
  • trembling and shaking of the hands and fingers, shuffling walk and stiffness of the arms and legs;
  • severe upper stomach pain, often with nausea, vomiting and fever.
  • Changes in the heart activity which can be seen on an electro-cardiogram (ECG) called ‘ prolonged QT interval’
  • fast irregular heartbeat, fainting which could be the symptoms of a life threatening condition known as Torsade de Pointes

The above list includes serious side effects which may require medical attention.

Go to hospital if...

Tell your doctor immediately or go to Accident and Emergency at your nearest hospital, if you notice any of the following:

  • any breathing difficulties;
  • sudden signs of allergy such as rash, itching or hives, swelling of the face, lips, tongue or other parts of the body, shortness of breath, wheezing or difficulty breathing;
  • fainting, especially if you have a slow or irregular heart beat;
  • vomiting blood or material that looks like coffee grounds;
  • black sticky bowel motions (stools);
  • convulsions or fits;
  • weakness, shortness of breath, yellowing of the skin, dark brown urine and stomach pain;
  • sudden increase in body temperature, sweating, muscle stiffness, or altered consciousness (awareness of oneself and ones surrounding).

The above list includes very serious side effects. You may need urgent medical attention or hospitalisation.

Tell your doctor or pharmacist if you notice anything else that is making you feel unwell. Other side effects not listed above may also occur in some people.

After taking Donepezil GH

Storage

Keep your tablets in their blister pack until it is time to take them. If you take the tablets out of the pack they may not keep well.

Keep your tablets in a cool, dry place where the temperature stays below 30°C.

Do not store it or any other medicine in the bathroom or near a sink. Do not leave it in the car or on window sills. Heat and dampness can destroy some medicines.

Keep it where children cannot reach it. A locked cupboard at least one-and-a-half metres above the ground is a good place to store medicines.

Disposal

If your doctor tells you to stop taking this medicine, or the expiry date has passed, ask your pharmacist what to do with any left over.

Product description

What it looks like

Donepezil GH 5 mg tablets are white to off white, circular, biconvex, film-coated tablets, embossed with ‘C’ on one side and ‘7’ on the other side.

Donepezil GH 10 mg tablets are yellow, circular, biconvex, film-coated tablets, embossed with ‘C’ on one side and ‘6’ on the other side.

Donepezil GH is supplied in blister packs of 28 tablets.

Ingredients

Active Ingredients

Each Donepezil GH tablet contains 5 mg or 10 mg donepezil hydrochloride (as monohydrate).

Inactive Ingredients

  • lactose monohydrate;
  • maize starch;
  • microcrystalline cellulose;
  • hyprolose;
  • sodium stearylfumarate;
  • purified talc;
  • macrogol 6000;
  • hypromellose;
  • titanium dioxide;
  • iron oxide yellow (10 mg tablet only).

Donepezil GH tablets do not contain gluten.

Australian Registration Numbers

Donepezil GH 5 mg: AUST R 193661

Donepezil GH 10 mg: AUST R 193667

Sponsor

Generic Health Pty Ltd
Suite 2, Level 2
19-23 Prospect Street
Box Hill, VIC, 3128
Australia

E-mail: [email protected]
Telephone: +61 3 9809 7900
Website: www.generichealth.com.au

This leaflet was prepared in September 2022

Published by MIMS December 2022

BRAND INFORMATION

Brand name

Donepezil GH

Active ingredient

Donepezil hydrochloride

Schedule

S4

 

1 Name of Medicine

Donepezil hydrochloride (as monohydrate).

2 Qualitative and Quantitative Composition

Donepezil GH film-coated tablets for oral administration are supplied containing 5 mg or 10 mg donepezil hydrochloride (as monohydrate) equivalent to 4.56 mg or 9.12 mg donepezil free base, respectively.

List of excipients with known effect.

Sugars as lactose.
For the full list of excipients, see Section 6.1 List of Excipients.

3 Pharmaceutical Form

Donepezil GH 5 mg film-coated tablets.

White to off white, circular, biconvex, film-coated tablets, embossed with 'C' on one side and '7' on the other side.

Donepezil GH 10 mg film-coated tablets.

Yellow, circular, biconvex, film-coated tablets, embossed with 'C' on one side and '6' on the other side.

4 Clinical Particulars

4.1 Therapeutic Indications

Donepezil GH is indicated for the treatment of mild, moderate and severe Alzheimer's disease.

4.2 Dose and Method of Administration

Adults/elderly.

Treatment should be initiated and supervised by a doctor experienced in the diagnosis and treatment of Alzheimer's Dementia. Individual response to donepezil cannot be predicted. Treatment should be continued for as long as a therapeutic benefit for the patient exists. Discontinuation of therapy should be considered where there is no longer evidence of a therapeutic effect, which should be assessed by periodic evaluations by the physician using input from the patient and caregiver.
The dosages of donepezil shown to be effective in controlled clinical trials are 5 mg and 10 mg administered once daily. Although there is no statistically significant evidence that a greater treatment effect is obtained from the use of the 10 mg dose, there is a suggestion, based on analysis of group data, that some additional benefits may accrue to some patients from the use of the higher dose.
Treatment is initiated at 5 mg/day (once-a-day dosing). Donepezil GH tablets should be taken orally, in the evening, just prior to retiring. Donepezil GH can be taken with or without food.
The 5 mg/day dose should be maintained for at least one month in order to allow the earliest clinical responses to treatment to be assessed and to allow steady-state concentrations of donepezil hydrochloride to be achieved. Following a one-month clinical assessment of treatment at 5 mg/day, the dose of Donepezil GH can be increased to 10 mg/day (once-a-day dosing).
The maximum recommended daily dose is 10 mg. Doses greater than 10 mg/day have not been studied in clinical trials.
Upon discontinuation of treatment, a gradual abatement of the beneficial effects of donepezil is seen. There is no evidence of a rebound effect after abrupt discontinuation of therapy.

Use in renal and hepatic impairment.

A similar dose schedule can be followed for patients with renal or hepatic impairment as clearance of donepezil hydrochloride is not significantly affected by these conditions.

4.3 Contraindications

Donepezil GH is contraindicated in patients with a known hypersensitivity to donepezil hydrochloride, piperidine derivatives, or to any excipients used in the formulation.

4.4 Special Warnings and Precautions for Use

Anaesthesia.

Donepezil, as a cholinesterase inhibitor, is likely to exaggerate succinylcholine-type muscle relaxation during anaesthesia.

Cardiovascular conditions.

Because of their pharmacological action, cholinesterase inhibitors may have vagotonic effects on heart rate (e.g. bradycardia). The potential for this action may be particularly important to patients with 'sick sinus syndrome' or other supraventricular cardiac conduction conditions, such as sinoatrial or atrioventricular block.
In the severe Alzheimer's disease studies, mild to moderate bradycardia was reported (see Section 4.8 Adverse Effects (Undesirable Effects)).
There have been post-marketing reports of cardiac conduction conditions including atrioventricular block, QTc interval prolongation and Torsade de Pointes (see Section 4.5 Interactions with Other Medicines and Other Forms of Interactions; Section 4.8 Adverse Effects (Undesirable Effects)). Caution is advised in patients with pre-existing or family history of QTc prolongation, in patients being treated with drugs affecting the QTc interval, or in patients with relevant pre-existing cardiac disease (e.g. uncompensated heart failure, recent myocardial infarction, bradyarrhythmias), or electrolyte disturbances (hypokalaemia, hypomagnesaemia). Clinical monitoring (ECG) may be required.

Gastrointestinal conditions.

Through their primary action, cholinesterase inhibitors may be expected to increase gastric acid secretion due to increased cholinergic activity. Therefore, patients at increased risk of developing ulcers, e.g. those with a history of ulcer disease or those receiving concurrent nonsteroidal anti-inflammatory drugs (NSAIDs), should be monitored closely for symptoms of active or occult gastrointestinal bleeding. However, the clinical studies with donepezil showed no increase, relative to placebo, in the incidence of either peptic ulcer disease or gastrointestinal bleeding.
Donepezil hydrochloride, as a predictable consequence of its pharmacological properties, has been shown to produce diarrhoea, nausea and vomiting. Patients should be observed closely at the initiation of treatment and after dose increases.

Neurological conditions.

Seizures.

Cholinomimetics are believed to have some potential to cause generalised convulsions. However, seizure activity may also be a manifestation of Alzheimer's disease. Cholinomimetics have the potential to exacerbate or induce extrapyramidal symptoms.

Neuroleptic malignant syndrome (NMS).

NMS has been reported to occur very rarely in patients treated with donepezil, with or without concomitant antipsychotic medication. NMS is a potentially life-threatening condition characterised by hyperthermia, muscle rigidity, autonomic instability, altered consciousness and elevated serum creatine phosphokinase levels; additional signs may include myoglobinuria (rhabdomyolysis) and acute renal failure.
If a patient develops signs and symptoms indicative of NMS, or presents with unexplained high fever without additional clinical manifestations of NMS, treatment should be discontinued immediately.

Pulmonary conditions.

Because of their cholinomimetic actions, cholinesterase inhibitors should be prescribed with care to patients with a history of asthma or obstructive pulmonary disease.
The administration of donepezil hydrochloride concomitantly with other inhibitors of acetylcholinesterase, agonists or antagonists of the cholinergic system should be avoided.

Aggressive behaviour.

In patients with severe Alzheimer's disease, Donepezil GH should be used with caution in patients at risk of aggression (see Section 4.8 Adverse Effects (Undesirable Effects), Severe Alzheimer's disease).

Mortality in subjects with vascular dementia.

Three clinical trials of 6 months duration were conducted studying individuals meeting the NINDS-AIREN criteria for probable or possible vascular dementia (VaD) and excluding patients with a diagnosis of Alzheimer's disease. In the first study, the mortality rates were 2/198 (1.0%) on donepezil 5 mg, 5/206 (2.4%) on donepezil 10 mg and 7/199 (3.5%) on placebo. In the second study, the mortality rates were 4/208 (1.9%) on donepezil 5 mg, 3/215 (1.4%) on donepezil 10 mg and 1/193 (0.5%) on placebo. In the third study, the mortality rates were 11/648 (1.7%) on donepezil 5 mg and 0/326 (0%) on placebo (p < 0.02). The mortality rate for the three VaD studies combined in the donepezil group (1.7%) was numerically higher than in the placebo group (1.1%), however, this difference was not statistically significant. The majority of deaths in patients taking either donepezil or placebo appear to result from various vascular related causes which could be expected in this elderly population with underlying vascular disease. An analysis of all serious non-fatal and fatal vascular events showed no difference in the rate of occurrence in the donepezil group relative to placebo.
When Alzheimer's disease studies were pooled (n = 4,146), the mortality rate in the placebo group numerically exceeded that in the donepezil group. There is no evidence of an increased risk of mortality in the current approved indication of mild to moderately severe Alzheimer's disease.

Use in the elderly.

See Section 4.4 Special Warnings and Precautions for Use, Mortality in subjects with vascular dementia.

Paediatric use.

Donepezil GH is not recommended for use in children.

Effects on laboratory tests.

No notable abnormalities in laboratory values associated with treatment were observed except for minor increases in serum concentrations of creatine kinase.

4.5 Interactions with Other Medicines and Other Forms of Interactions

Drugs highly bound to plasma proteins.

Drug displacement studies have been performed in vitro between this highly bound drug (96%) and other drugs such as frusemide, digoxin, and warfarin. Donepezil at concentrations of 0.3-10 microgram/mL did not affect the binding of frusemide (5 microgram/mL), digoxin (2 nanogram/mL) and warfarin (3 microgram/mL) to human albumin. Similarly, the binding of donepezil to human albumin was not affected by frusemide, digoxin and warfarin.

Drug-drug interactions.

Cases of QTc interval prolongation and Torsade de Pointes have been reported for donepezil (see Section 4.4 Special Warnings and Precautions for Use; Section 4.8 Adverse Effects (Undesirable Effects)). Caution is advised when donepezil is used in combination with other medicinal products known to prolong the QTc interval and clinical monitoring may be required.
Examples include:
Class IA antiarrhythmics (e.g. disopyramide);
Class III antiarrhythmics (e.g. amiodarone, sotalol);
Certain antidepressants (e.g. citalopram, escitalopram, amitriptyline);
Other antipsychotics (e.g. phenothiazine derivatives, pimozide, ziprasidone);
Certain antibiotics (e.g. clarithromycin, erythromycin, moxifloxacin).

Effect of donepezil on other medicines.

No in vivo clinical trials have investigated the effect of donepezil on the clearance of drugs metabolised by CYP 3A4 (e.g. cisapride, terfenadine) or by CYP 2D6 (e.g. imipramine). However, in vitro studies show a low rate of binding to these enzymes (mean Ki about 50-130 microM), that, given the therapeutic plasma concentrations of donepezil (164 nanoM), indicates little likelihood of interference.
Whether donepezil has any potential for enzyme induction is not known.
Formal pharmacokinetic studies evaluated the potential of donepezil for interaction with theophylline, cimetidine, warfarin and digoxin. No significant effects on the pharmacokinetics of these drugs were observed.

Effect of other medicines on donepezil.

Ketoconazole and quinidine, inhibitors of CYP450, 3A4 and 2D6, respectively, inhibit donepezil metabolism in vitro. Whether there is a clinical effect of these inhibitors is not known. In a study in healthy volunteers, ketoconazole increased mean donepezil concentrations by about 30%. Inducers of CYP 2D6 and CYP 3A4 (e.g. phenytoin, carbamazepine, dexamethasone, rifampicin, and phenobarbital) could increase the rate of elimination of donepezil.
Formal pharmacokinetic studies demonstrated that the metabolism of donepezil is not significantly affected by concurrent administration of digoxin or cimetidine.
Donepezil has the potential to interfere with medications having anticholinergic activity. There is also the potential for synergistic activity with concomitant treatment involving medications such as succinylcholine, other neuro-muscular blocking agents or cholinergic agonists or beta-blocking agents which have effects on cardiac conduction.

4.6 Fertility, Pregnancy and Lactation

Effects on fertility.

Donepezil had no effect on fertility in rats at oral doses up to 10 mg/kg/day (a tissue exposure equivalent to approximately twice that in humans at the maximum recommended clinical dose of 10 mg/day) in male and female rats based on AUC.
(Category B3)
Teratology studies conducted in pregnant rats at oral doses up to 16 mg/kg/day and in pregnant rabbits at doses up to 10 mg/kg/day did not disclose any evidence for a teratogenic potential of donepezil. In rats this dose resulted in a systemic drug exposure in excess of human values. However, in rabbits the extent of systemic drug exposure is not known. Treatment of pregnant rats from late gestation to the end of lactation with an oral donepezil dose of 10 mg/kg/day resulted in a slight increase in incidence of stillborn pups, and slightly reduced pup survival through day 4 postpartum.
There are no adequate or well-controlled studies in pregnant women. Donepezil hydrochloride should be used in pregnancy only if the potential benefit justifies the potential risk to the foetus.
 It is not known whether donepezil hydrochloride is excreted in human breast milk and there are no studies in lactating women. Excretion of donepezil and/or its metabolites into milk occurred after oral treatment of nursing rats, with milk concentrations similar to those in plasma. Therefore, women on donepezil should not breast feed.

4.7 Effects on Ability to Drive and Use Machines

Alzheimer's dementia may cause impairment of driving performance or compromise the ability to use machinery. Furthermore, donepezil can cause fatigue, dizziness and muscle cramps, mainly when initiating or increasing the dose. The ability of Alzheimer patients on donepezil to continue driving or operating complex machinery should be routinely evaluated by the treating physician.

4.8 Adverse Effects (Undesirable Effects)

Most adverse events are mild in severity and transient in nature. The most common (incidence ≥ 5% and twice the frequency of placebo) were diarrhoea, muscle cramps, fatigue, nausea, vomiting and insomnia.
Other common adverse events (incidence ≥ 5% and ≥ placebo) were headache, pain, accident, common cold, abdominal disturbance and dizziness. Cases of syncope, bradycardia, sinoatrial block and atrioventricular block were observed.
No notable abnormalities in laboratory values associated with treatment were observed except for minor increases in serum concentrations of creatine kinase.
Adverse events observed during long-term but not the short-term trials (incidence ≥ 5% and twice the frequency of placebo) included asthenia.

Adverse events leading to discontinuation.

The rate of discontinuation for the donepezil 5 mg/day treatment group was comparable to that of placebo-treated patients at approximately 5%. The rate of discontinuation of patients who received rapid dose escalations over 7 days from 5 mg/day to 10 mg/day, was higher at 13%. The most common signs and symptoms leading to discontinuation were nausea, diarrhoea and vomiting. For patients who did not discontinue, these signs and symptoms generally proved to be mild and transient, resolving in 1 to 2 days during continued use of the 10 mg/day dose. There is evidence to suggest that the frequency of these common adverse events may be affected by the rate of titration.
Adverse events listed in Table 1 were derived from the 15- and 30-week studies (see Section 5.1 Pharmacodynamic Properties, Clinical trials) and a pivotal study of 14 weeks duration.

Other adverse events observed during clinical trials.

Treatment emergent signs and symptoms that occurred during three controlled clinical trials were recorded as adverse events by the clinical investigators using terminology of their own choosing. All adverse events occurring at least twice and judged as possibly or definitely related to donepezil treatment are included, except for those already listed in Table 1. Events are classified by body system and include frequent adverse events - those occurring in at least 1/100 patients; infrequent adverse events - those occurring in 1/100 to 1/1,000 patients.

Body as a whole.

Generalised weakness, infection, influenza, assault.

Cardiovascular system.

Vasodilation, hot flashes, hypotension, angina pectoris, hypertension.

Digestive system.

Abdominal disturbance, constipation, faecal incontinence, bloating, stomach upset, epigastric pain, eructation, gastrointestinal bleeding, increased appetite, flatulence, drooling, dry mouth, increased transaminases.

Metabolic and nutritional disorders.

Dehydration, oedema of extremities.

Musculoskeletal system.

Muscle weakness.

Nervous system.

Agitation, anxiety, confusion, delusions, hallucinations, tremor, irritability, aggression, vertigo, ataxia, increased libido, restlessness, abnormal crying, aphasia, coldness (localised), muscle spasm, hypokinesia, nervousness, paraesthesia, paranoia, wandering.

Respiratory system.

Rhinitis, coughing, dyspnoea.

Skin and appendages.

Rash, abrasion, diaphoresis, pruritus.

Special senses.

Cataract, ear disorder, vision blurred.

Urogenital system.

Urinary incontinence, urinary tract infection, nocturia.

Post-marketing experience.

There have been post-marketing reports of hallucinations, agitation, aggressive behaviour, seizure, hepatitis, gastric ulcer, duodenal ulcer, gastrointestinal haemorrhage, abdominal pain, cholecystitis, heart block, electrocardiogram QT interval prolonged, polymorphic ventricular tachycardia including Torsade de Pointes (see Section 4.4 Special Warnings and Precautions for Use; Section 4.5 Interactions with Other Medicines and Other Forms of Interactions), haemolytic anaemia, hyponatraemia, neuroleptic malignant syndrome and pancreatitis.

Severe Alzheimer's disease.

A total of 573 patients with severe Alzheimer's disease were treated in controlled clinical studies with donepezil. Of these patients, 441 (77%) completed the studies. The mean duration of treatment for all donepezil groups was 148.4 days (range 1-231 days).
The incidence profile for adverse events for severe Alzheimer's disease was similar to that of mild to moderate Alzheimer's disease.
In controlled clinical trials in severe Alzheimer's disease, the rate of discontinuation due to adverse events was 11.3% in patients treated with donepezil compared to 6.7% in the placebo group. No individual adverse event led to discontinuation in greater than 2% of patients. Other less common adverse events leading to discontinuation included diarrhoea, nausea, vomiting, urinary tract infection, decreased appetite, and aggression.
The most common adverse events, defined as those occurring at a frequency of at least 5% in patients and twice the placebo rate, were diarrhoea, nausea, and aggression. The incidence of aggression was increased in men, occurring in 11.2% of men who received donepezil, compared with 3.1% who received placebo. In women, aggression was seen in 2.9% of donepezil patients versus 2.1% of placebo patients. Overall, the majority of adverse events were judged by the investigators to be mild or moderate in intensity.
Adverse events presented by age (< 75 years and ≥ 75 years) and treatment are shown in Table 2. Overall, the incidence of common adverse events was similar between age groups by treatment. The incidence of falls increased with age in both treatment groups, as did the incidence of urinary tract infections and vomiting. The incidence of diarrhoea did not correlate with age, but was related to treatment. The incidence of nausea was less in the ≥ 75-year age group but related to treatment.

Reporting suspected adverse effects.

Reporting suspected adverse reactions after registration of the medicinal product is important. It allows continued monitoring of the benefit-risk balance of the medicinal product. Healthcare professionals are asked to report any suspected adverse reactions at www.tga.gov.au/reporting-problems.

4.9 Overdose

Symptoms.

Overdosage with cholinesterase inhibitors can result in cholinergic crisis characterised by severe nausea, vomiting, miosis, lacrimation, salivation, sweating, flushing, bradycardia, involuntary urination and/or defecation, bronchospasm, increased bronchial secretions, respiratory depression, collapse and convulsions/seizures. Hypotension following overdose could be severe leading to cardiovascular collapse or shock. Abdominal pain, diarrhoea, increased micturition, diaphoresis, vertigo, fasciculations, tremors, agitation, lethargy, syncope and coma may occur. Various dysrhythmias, primarily heart block, may theoretically occur due to cholinergic effects. Increasing muscle weakness is a possibility and may result in death if respiratory muscles are involved. Due to its high degree of selectivity for acetylcholinesterase (AChE) in the CNS and less peripheral selectivity, overdoses would be expected to exhibit more CNS-related symptomatology, including extrapyramidal effects.
Overdoses of 45 mg and 50 mg in two elderly patients resulted in minimal effects, predominately gastrointestinal, and in one case persistent bradycardia (HR in the 40's) both with uneventful recoveries.

Treatment.

As in any case of overdose, general supportive measures should be utilised. Cholinesterase activity may be depressed and should be monitored in plasma (pseudocholinesterase) and red blood cells. Monitor ECG following significant exposures. Monitor pulse oximetry and/or arterial blood gases and obtain a chest radiograph in patients with pulmonary symptoms. Tertiary anticholinergics such as atropine may be used as an antidote for Donepezil GH overdosage. Intravenous atropine sulphate titrated to effect is recommended: an initial dose of 1.0 to 2.0 mg IV with subsequent doses based upon clinical response. Atypical responses in blood pressure and heart rate have been reported with other cholinomimetics when co-administered with quaternary anticholinergics such as glycopyrrolate. Consider administration of activated charcoal in the event of a potentially toxic ingestion. Activated charcoal is most effective when administered within one hour of ingestion. In patients who are not fully conscious or have impaired gag reflex, consideration should be given to administering activated charcoal via nasogastric tube once the airway is protected. It is not known whether donepezil and/or its metabolites can be removed by dialysis (haemodialysis, peritoneal dialysis, or haemofiltration). Emesis is not recommended because of the potential for CNS depression and seizures.
For information on the management of overdose, contact the Poisons Information Centre on 13 11 26 (Australia).

5 Pharmacological Properties

5.1 Pharmacodynamic Properties

Mechanism of action.

It has been demonstrated that Alzheimer's disease is associated with a relative decrease in the activity of the cholinergic system in the cerebral cortex and other areas of the brain. Studies suggest that donepezil hydrochloride exerts its therapeutic effect by enhancing cholinergic function in the central nervous system. This is accomplished by increasing the concentration of acetylcholine through reversible inhibition of acetylcholinesterase.

Pharmacodynamics.

Donepezil hydrochloride is a specific and reversible inhibitor of acetylcholinesterase, the predominant cholinesterase in the brain. Donepezil hydrochloride was found in vitro to be over 1,000 times more potent an inhibitor of this enzyme than of butyrylcholinesterase, an enzyme which is present mainly outside the central nervous system.
In patients with Alzheimer's Dementia participating in clinical trials, administration of single daily doses of 5 mg or 10 mg donepezil produced steady-state inhibition of acetylcholinesterase activity (measured in erythrocyte membranes) of 63.6% and 77.3%, respectively when measured post-dose. The inhibition of AChE in red blood cells by donepezil hydrochloride has been shown to correspond closely to the effects in the cerebral cortex. In addition, significant correlation was demonstrated between plasma levels of donepezil hydrochloride, AChE inhibition and change in Alzheimer's Disease Assessment Scale (ADAS-cog), a sensitive and well validated scale which examines cognitive performance - including memory, orientation, attention, reason, language and praxis.

Clinical trials.

Mild to moderately severe Alzheimer's disease.

Studies of less than one year duration. The effectiveness of donepezil in the treatment of Alzheimer's disease has been demonstrated by two randomised, double-blind, placebo-controlled studies (15- and 30-week) in which 436 patients were treated with donepezil hydrochloride. Criteria for inclusion were patients with mild to moderately severe Alzheimer's disease (diagnosed by NINCDS and DSM III-R criteria, Mini-Mental State Examination ≥ 10 and ≤ 26 and Clinical Dementia Rating of 1 or 2).

Study outcome measures.

In each study, the effectiveness of treatment with donepezil was evaluated using a dual outcome assessment strategy.
The ability of donepezil to improve cognitive performance was assessed with the cognitive subscale of the ADAS-cog, a multi-item instrument that has been extensively validated in longitudinal cohorts of Alzheimer's disease patients. The ADAS-cog examines selected aspects of cognitive performance including elements of memory, orientation, attention, reasoning, language and praxis. The ADAS-cog scoring range is from 0 to 70, with higher scores indicating greater cognitive impairment. Elderly normal adults may score as low as 0 or 1, but it is not unusual for non-demented adults to score slightly higher.
The patients recruited as participants in each study had mean scores on the ADAS-cog of approximately 26 units, with a range from 4 to 61. Experience gained in longitudinal studies of ambulatory patients with mild to moderate Alzheimer's disease suggest that they gain 6 to 12 units a year on the ADAS-cog. However, lesser degrees of change are seen in patients with very mild or very advanced disease because the ADAS-cog is not uniformly sensitive to change over the course of the disease. The annualised rate of decline in the placebo patients participating in donepezil trials was approximately 2 to 4 units per year.
The ability of donepezil to produce an overall clinical effect was assessed using a Clinician's Interview Based Impression of Change that required the use of caregiver information, the CIBIC plus. Unlike ADAS-cog, the CIBIC plus is not a single instrument nor is it a standardised instrument like the ADAS-cog. Clinical trials for investigational drugs have used a variety of CIBIC formats, each different in terms of depth and structure. As such, results from a CIBIC plus reflect clinical experience from the trial or trials in which it was used and cannot be compared directly with the results of CIBIC plus evaluations from other clinical trials. The CIBIC plus used in donepezil trials was a semi-structured instrument that was intended to examine four major areas of patient function: General, Cognitive, Behavioural and Activities of Daily Living. It represents the assessment of a skilled clinician based upon his/her observations at an interview with the patient, in combination with information supplied by a caregiver familiar with the behaviour of the patient over the interval rated. The CIBIC plus is scored as a seven point categorical rating, ranging from a score of 1, indicating 'markedly improved', to a score of 4, indicating 'no change' to a score of 7, indicating 'markedly worse'. The CIBIC plus has not been systematically compared directly to assessments not using information from caregivers (CIBIC) or other global methods.
Thirty-week study. In a study of 30 weeks duration, 473 patients were randomised to receive single daily doses of placebo, 5 mg/day or 10 mg/day of donepezil. The 30-week study was divided into a 24-week double-blind active treatment phase followed by a 6-week single-blind placebo washout period. The study was designed to compare 5 mg/day or 10 mg/day fixed doses of donepezil to placebo. However, to reduce the likelihood of cholinergic effects, the 10 mg/day treatment was started following an initial 7-day treatment with 5 mg/day doses.

Effects on the ADAS-cog.

Figure 1 illustrates the time course for the change from baseline in ADAS-cog scores for all three dose groups over the 30 weeks of the study. After 24 weeks of treatment; the mean differences in the ADAS-cog change scores for donepezil-treated patients compared to the patients on placebo were 2.8 and 3.1 units for the 5 mg/day and 10 mg/day treatments, respectively. These differences were statistically significant. While the treatment effect size may appear to be slightly greater for the 10 mg/day treatment, there was no statistically significant difference between the two active treatments.
Following 6 weeks of placebo washout, scores on the ADAS-cog for both the donepezil treatment groups were indistinguishable from those patients who had received only placebo for 30 weeks. This suggests that the beneficial effects of donepezil abate over 6 weeks following discontinuation of treatment and do not represent a change in the underlying disease. There is no evidence of a rebound effect 6 weeks after abrupt discontinuation of therapy.
Figure 2 illustrates the cumulative percentages of patients from each of the three treatment groups who had attained the measure of improvement in ADAS-cog score shown on the X axis. Three change scores (7-point and 4-point reductions from baseline or no change in score) have been identified for illustrative purposes and the percent of patients in each group achieving that result is shown in this inset table.
The curves demonstrate that both patients assigned to placebo and donepezil have a wide range of responses, but that the active treatment groups are more likely to show greater improvements. A curve for an effective treatment would be shifted to the left of the curve for placebo, while an ineffective or deleterious treatment would be superimposed upon or shifted to the right of the curve for placebo, respectively.

Effects on the CIBIC plus.

Figure 3 is a histogram of the frequency distribution of CIBIC plus scores attained by patients assigned to each of the three treatment groups who completed 24 weeks of treatment. The mean drug-placebo differences for these groups of patients were 0.35 units and 0.39 units for 5 mg/day and 10 mg/day of donepezil, respectively. These differences were statistically significant. There was no statistically significant difference between the two active treatments.
Fifteen-week study. In a study of 15 weeks duration, patients were randomised to receive single daily doses of placebo or either 5 mg/day or 10 mg/day of donepezil for 12 weeks, followed by a 3-week placebo washout period. As in the 30-week study, to avoid acute cholinergic effects, the 10 mg/day treatment followed an initial 7-day treatment with 5 mg/day doses.

Effects on the ADAS-Cog.

Figure 4 illustrates the time course of the change from baseline in ADAS-cog scores for all three dose groups over the 15 weeks of the study. After 12 weeks of treatment, the differences in mean ADAS-cog change scores for the donepezil-treated patients compared to the patients on placebo were 2.7 and 3.0 units each, for the 5 and 10 mg/day donepezil treatment groups respectively. These differences were statistically significant. The effect size for the 10 mg/day group may appear to be slightly larger than that for 5 mg/day. However, the differences between active treatments were not statistically significant.
Following 3 weeks of placebo washout, scores on the ADAS-cog for both the donepezil treatment groups increased, indicating that discontinuation of donepezil resulted in a loss of its treatment effect. The duration of this placebo washout period was not sufficient to characterise the rate of loss of the treatment effect, but the 30-week study (see above) demonstrated that treatment effects associated with the use of donepezil abate within 6 weeks of treatment discontinuation.
Figure 5 illustrates the cumulative percentages of patients from each of the three treatment groups who attained the measure of improvement in ADAS-cog score shown on the X axis. The same three change scores (7-point and 4-point reductions from baseline or no change in score) as selected for the 30-week study have been used for this illustration. The percentages of patients achieving those results are shown in the inset table.
As observed in the 30-week study, the curves demonstrate that patients assigned to either placebo or to donepezil have a wide range of responses, but that the donepezil-treated patients are more likely to show the greater improvements in cognitive performance.

Effects on the CIBIC plus.

Figure 6 is a histogram of the frequency distribution of CIBIC plus scores attained by patients assigned to each of the three treatment groups who completed 12 weeks of treatment. The differences in mean scores for donepezil-treated patients compared to the patients on placebo at Week 12 were 0.36 and 0.38 units for the 5 mg/day and 10 mg/day treatment groups, respectively. These differences were statistically significant.
In both studies, patient age, sex and race were not found to predict the clinical outcome of donepezil treatment.
Studies of greater than one year duration. The effectiveness of donepezil in the treatment of Alzheimer's disease has been demonstrated by two randomised, double-blind, placebo-controlled studies (54-week) in which 356 patients were treated with donepezil.
Fifty-four-week study #1. In a 54-week double-blinded study, patients were randomised to receive either placebo or 5 mg donepezil once daily for 28 days followed by 10 mg once daily for the remainder of the study. Criteria for inclusion included: diagnosis of mild to moderate Alzheimer's disease (DSM-IV, 290.00 or 290.10 of the NINCDS criteria), Clinical Dementia Rating (CDR) = 1 or 2, MMSE of 12-20, retention of at least 8 Instrumental Activities of Daily Living (IADLs) and at least 5 basic Activities of Daily Living (ADLs) and a modified Hachinski score ≤ 4. The intent to treat analysis consisted of 207 donepezil-treated patients and 208 placebo patients.

Study outcome measure.

The primary outcome measure for assessment of efficacy of donepezil was based upon attrition from the study due to clinically evident functional decline. Patients were assessed at 6-week intervals. Attrition was determined by the investigator as follows: 1) a clinically significant decline in ability to perform one or more basic ADL which were present at baseline, 2) a clinically significant decline in ability to perform 20% or more of IADLs which were present at baseline, or 3) an increase in CDR score compared to baseline.
Basic ADL items are defined by the patient's ability in toileting, feeding, dressing, personal hygiene/grooming, bathing and walking. Instrumental ADLs involve the assessment of 10 items; use of telephone, household tasks, using household appliances, managing money, shopping, food preparations, ability to get around inside and outside home, hobbies and leisure activities, handling personal mail, and grasp of situations or explanations. The CDR assesses six cognitive and behavioural domains: memory, orientation, judgement and problem solving, community affairs, home and hobbies and personal care.

Time to attrition.

In the Kaplan-Meier analysis, donepezil treatment produced significantly greater preservation of function, as determined by time to attrition, than placebo as illustrated in Figure 7. By using Log-rank and Wilcoxon tests to compare survival distribution of time to attrition, the median time to attrition was more than 357 days (lower limit of the 95% CI = 280) for donepezil-treated patients, whereas the median time to attrition for placebo-treated patients was 208 days (95% CI = [165, 252]). Both Log-rank and Wilcoxon tests indicated that the survival curves for the two treatment groups were significantly different (p = 0.0019 and p = 0.0051, respectively).
The hazard ratio (donepezil/placebo) was 0.62 indicating the relative risk of clinically evident function decline for patients who received donepezil was approximately 62% of that of patients who received placebo.
Fifty-four-week study #2. In a study of 54 weeks duration, patients were randomised to receive either placebo or 5 mg donepezil once daily, which was increased to 10 mg once daily at day 29 and maintained until the end of the study. Criteria for inclusion included a diagnosis of mild to moderate Alzheimer's disease (DSM-IV, NINCDS-ADRDA criteria and MMSE of 10-26).

Study outcome measure.

The primary efficacy variable was the Gottfries, Brane and Steen (GBS) scale, which assesses global function. It is based on a semi-structured interview with the patient's caregiver. This 27-item scale assesses four domains including intellectual function (12 items), motor function (basic ADLs - 6 items), emotional function (3 items) and behavioural symptoms characteristic for dementia syndromes (6 items).

Global function.

On the GBS scale, donepezil-treated patients showed a trend to improvement compared to placebo patients at endpoint analysis (p = 0.054). By intention to treat analysis of observed cases, donepezil-treated patients performed significantly better than placebo patients at 24, 36 and 52 weeks. See Figure 8.

Quality of life.

Although a trend of improvement on quality of life (QOL) measures was observed in clinical trials of donepezil-treated patients, there were large variances in QOL scores. These are consistent with observations regarding quality of life assessments in Alzheimer's disease patients generally. It has been demonstrated that Alzheimer's disease patients' opinions will be influenced by the day-to-day fluctuations in their illness (often quite substantial), leading to similar day-to-day variability in their perception of quality of life. Alzheimer's disease patients may also be unreliable sources of information on quality of life because of significant losses in executive functions such as judgement and insight, that are key to obtaining meaningful assessments.

Severe Alzheimer's disease.

The effectiveness of donepezil in the treatment of severe Alzheimer's disease has been demonstrated by three randomised, double-blind, placebo-controlled studies (one 26-week and two 24-week) in which 517 patients were randomised to receive donepezil. Criteria for inclusion were patients with severe Alzheimer's disease (diagnosed by NINCDS-ADRDA and DSM IV criteria, Mini-Mental State Examination (MMSE) and a Functional Assessment Staging (FAST).
Study outcome measures. In each study, the effectiveness of treatment with donepezil was evaluated using a combination of assessments of cognition, global function, activities of daily living (daily function), and behavioural and psychological symptoms.
Cognition.

SIB.

The primary tool in the three studies used to assess cognition was the Severe Impairment Battery (SIB). The SIB evaluates cognitive dysfunction over nine domains (social interactions, memory, orientation, language, attention, praxis, visuospatial, construction and orienting to name). Total scores range from 1 to 100, and lower scores indicate greater impairment.

MMSE.

Cognitive changes over time are often assessed using the Mini-Mental State Examination (MMSE), a 30-point test. Lower scores indicate a greater degree of impairment, and scores ≤ 12 points or ≤ 10 points have been used to define the severe stages of dementia. The MMSE was used in two of the studies as a secondary endpoint.
Global function.

CIBIC plus.

Similar to the studies in mild to moderate Alzheimer's disease, the Clinician's Interview Based Impression of Change with caregiver input (CIBIC plus) was used as a primary endpoint to assess global function for two of the three studies.

CGI-I.

In one of the studies, the Clinical Global Impression of Improvement (CGI-I) was used as a primary endpoint as a measure of global function. Similar to CIBIC plus, the physician rates the patient's condition relative to baseline on a 7-point Likert-like scale, with scores of 1-3 representing degrees of improvement, 4 representing no change, and 5-7 representing degrees of worsening.
Activities of daily living.

ADCS-ADL-severe.

To assess activities of daily living (ADL), all three studies used the modified ADCS-ADL inventory for severe Alzheimer's disease (ADCS-ADL-severe). This is based on an interview with the caregiver and measures the patient's most usual and consistent ability to perform basic and instrumental ADL during the previous 4 weeks. The scale ranges from 0 to 54, with lower scores indicating greater functional impairment.
Behavioural and psychological symptoms. Two scales were used to assess behavioural and psychological symptoms: the neuropsychiatric inventory (NPI) and the Behavioural Pathology in Alzheimer's disease scale (BEHAVE-AD).

NPI.

The 12 item NPI, used in two studies, is based on the caregiver's assessment of the frequency and severity of a range of mood and behavioural disturbances since the last evaluation. Total NPI scores range from 0 (best score) to 144 (worst score).

BEHAVE-AD.

The BEHAVE-AD scale, used in 1 study, is similarly based on the caregiver's assessment of the presence and magnitude of a range of neuropsychiatric symptoms over the past 2 weeks. Total BEHAVE-AD scores range from 0 (best score) to 78 (worst score).
Overall efficacy results from the three severe studies. Overall, donepezil-treated patients significantly benefited compared with placebo for the outcome measures of SIB scores, CIBIC plus scores, ADCS-ADL-severe scores and MMSE. Table 3 shows the pooled efficacy results, which have also been stratified by age. There was no significant age by treatment interaction for any of the measures in this pooled analysis. It is important to note that efficacy results stratified by age are a sub-group analysis. The studies were not powered to demonstrate efficacy in these subgroup analyses, and the results must be interpreted with caution.
In addition, in the three severe Alzheimer's disease studies, SIB scores, CIBIC plus/CGI-I scores and ADCS-ADL-severe scores were also not influenced by gender or by the diagnosis as probable or possible Alzheimer's disease.
Individual study description and efficacy results for the 26-week and the two 24-week studies are shown below.
Twenty-six-week study. In a study of 26 weeks duration, safety and efficacy were evaluated by randomising 249 patients to receive a single daily dose of placebo or 10 mg/day of donepezil. To reduce the likelihood of cholinergic effects, treatment was initiated at 5 mg/day for 4 weeks, then treatment was increased to 10 mg/day, based on clinical judgement. At any time during the study, the dose of donepezil could be reduced from 10 mg to 5 mg daily based on the investigator's assessment of tolerability. The primary endpoints for this study were the effects on the SIB and the ADCS-ADL-severe scores.
After 26 weeks of treatment, the mean difference in the SIB change scores for donepezil-treated patients compared with placebo was 5.7 points. The difference was statistically significant (p=0.008). For the effect on the ADCS-ADL-severe score, the donepezil-treated patients also showed significantly less decline (-1.4 points) than the patients on placebo (-3.0 points) (p=0.029). In this study MMSE, NPI, and CGI-I were used as secondary endpoints. Donepezil treated patients showed a significantly greater mean improvement (1.5 points) than placebo-treated patients (0.1 points) in the MMSE score (p = 0.008). There was no statistically significant difference between the treatment groups for the NPI (p = 0.426). The percentage of patients showing any degree of improvement in the CGI-I was 53.2% for donepezil-treated patients and 38.3% in the placebo (p = 0.055), while the distribution for patients in the worsened category was greater for the placebo-treated patients (25.2% placebo versus 20.7% donepezil-treated).
For those patients who discontinued, placebo-treated patients withdrew slightly later than donepezil-treated patients (median time to withdrawal 72 days following placebo compared to 70 days following donepezil). More patients remained on placebo treatment (82.5%) than on donepezil treatment (74.2%). The difference was not statistically significant (Table 4).
Twenty-four-week study #1. In a study of 24 weeks duration, 343 patients were randomised to receive single daily doses of placebo or 10 mg/day of donepezil. Patients received 5 mg for the first 6 weeks of the study and then 10 mg for the remainder of the double-blind period. At any time during the study, the dose of donepezil could be reduced from 10 mg to 5 mg daily based on the investigator's assessment of tolerability. The primary endpoints for this study were the effects on the SIB and the CIBIC plus scores.
After 24 weeks of treatment, the mean difference in the SIB change scores for donepezil-treated patients compared with was 5.3 points (p = 0.0001). The percentage of patients showing any degree of improvement on their CIBIC plus score was 27.8% for donepezil-treated patients and 22.7% for the placebo group (p = 0.09). For the other outcome measures donepezil-treated patients showed a significantly greater mean improvement (0.7 points) than placebo-treated patients (0.0 points) in the MMSE score (p = 0.0267). There were no statistically significant differences between the treatment groups for the ADCS-ADL-sev or NPI scales.
For those patients who discontinued, donepezil-treated patients withdrew somewhat sooner (median time 65 days) than placebo-treated patients (median time 75 days). Statistically significantly more patients remained on treatment in the placebo-treated group (76.0%) than in the donepezil-treated group (66.5%) (Table 5).
Long term efficacy data are provided by an open label extension of this study. After 36 weeks of donepezil treatment, the mean SIB value remained at or near the baseline level, suggesting no further decline in cognitive functions.
Twenty-four-week study #2. In a study of 24 weeks duration, 325 patients were randomised to receive single daily doses of placebo, low dose donepezil or high dose donepezil. For the low dose 3 mg/daily were administered for the first 2 weeks, then this was increased to 5 mg/day. For the high does group, 3 mg/day was administered for the first 2 weeks, then 5 mg/day were administered for 4 weeks, and from week 6 onwards, 10 mg/day were administered. Patients assigned to the 10 mg group needed to be able to tolerate the 10 mg/day dose to continue with the study. Patients who could not tolerate this dose were discontinued from the study. The primary endpoints used were the SIB score and the CIBIC-plus score.
After 24 weeks of treatment, the donepezil-treated patients showed a mean improvement in SIB (6.7 points in the 5 mg group and 8.9 points in the 10 mg group) compared with placebo. At both dose levels the difference was statistically significant (p < 0.0001 at each level). For the effect on global function, the percentage of patients showing any degree of improvement was 46.7% in the group treated with 10 mg of donepezil, 32.3% for the 5 mg donepezil-treated group and 23.8% for placebo-treated-patients. The difference was significantly different for the 10 mg group (p = 0.003), but not for the 5 mg group (p = 0.151). There were no statistically significant differences between the treatment groups for the ADCS-ADL-sev and BEHAVE-AD scales.
More patients on 5 mg remained on treatment (87.1%) than on 10 mg (79.2%) or on placebo (80.0%), although the difference was not statistically significant (Table 6). For those patients who discontinued, patients withdrew soonest for the 5 mg group (median time 55 days) followed by the 10 mg group (median time 65 days) followed by the placebo group (median time 83 days).

5.2 Pharmacokinetic Properties

Absorption.

Donepezil is well absorbed with a relative oral bioavailability of 100% and reaches peak plasma concentrations in 3 to 4 hours. Oral administration of donepezil produces highly predictable plasma concentrations with plasma concentrations and area under the curve rise in proportion to the dose.
The terminal disposition half-life is approximately 70 hours, thus, administration of multiple single-daily doses results in gradual approach to steady-state. Approximate steady-state is achieved within 3 weeks after the initiation of therapy. Once at steady-state, plasma donepezil hydrochloride concentrations and the related pharmacodynamic activity show little variability over the course of the day.
Neither food nor time of administration (morning versus evening dose) affect the absorption of donepezil hydrochloride.

Distribution.

The steady-state volume of distribution is 12 L/kg. Donepezil hydrochloride is approximately 96% bound to human plasma proteins. The distribution of donepezil hydrochloride in various body tissues has not been definitively studied. However, in a mass balance study conducted in healthy male volunteers, 240 hours after the administration of a single 5 mg dose of 14C-labelled donepezil hydrochloride, approximately 28% of the label remained unrecovered. This suggests that donepezil and/or its metabolites may persist in the body for more than 10 days.
The average CSF:plasma ratio for both doses, expressed as a percent of the concentration in plasma, was 15.7%.

Metabolism and excretion.

Donepezil is both excreted in the urine intact and extensively metabolised to four major metabolites, two of which are known to be active, and a number of minor metabolites, not all of which have been identified. Three of the human metabolites of donepezil have not undergone extensive safety tests in animals. These comprise two O-demethylated derivatives and an N-oxidation product. Donepezil is metabolised by CYP 450 isoenzymes 2D6 and 3A4 and undergoes glucuronidation. The rate of metabolism of donepezil is slow and does not appear to be saturable. These findings are consistent with the results from formal pharmacokinetic studies which showed that donepezil and/or its metabolites does not inhibit the metabolism of theophylline, warfarin, cimetidine, or digoxin in humans. Pharmacokinetic studies also demonstrated that the metabolism of donepezil is not affected by concurrent administration of digoxin or cimetidine (see Section 4.5 Interactions with Other Medicines and Other Forms of Interactions).
Following administration of 14C-labelled donepezil, plasma radioactivity, expressed as a percent of the administered dose, was present primarily as intact donepezil (53%) and as 6-O desmethyl donepezil (11%), which has been reported to inhibit AChE to the same extent as donepezil in vitro and was found in the plasma at concentrations equal to about 20% of donepezil. Approximately 57% and 15% of the total radioactivity was recovered in urine and faeces, respectively, over a period of 10 days, while 28% remained unrecovered, with about 17% of the donepezil dose recovered in the urine as unchanged drug.
There is no evidence to suggest enterohepatic re-circulation of donepezil and/or any of its metabolites.
Plasma donepezil concentrations decline with a half-life of approximately 70 hours.

Special populations.

Sex, race and smoking history have no clinically significant influence on plasma concentrations of donepezil.

Pharmacokinetic/dynamic properties.

Characteristics in patients.

As an inhibitor of AChE, donepezil augments cholinergic function in the central nervous system, thereby providing its therapeutic benefit. The enzyme AChE also occurs peripherally in red blood cells, therefore, measurement of AChE activity in erythrocyte membranes provides an index for donepezil pharmacodynamics. This surrogate marker has been evaluated in several human pharmacokinetic/pharmacodynamic trials and in controlled clinical trials.
The population plasma donepezil concentrations and red blood cell AChE inhibition measurements verified that patients in clinical trials experienced exposure to donepezil hydrochloride and its pharmacodynamic actions as predicted.
Results from therapeutic drug monitoring showed no apparent relationship between plasma concentration and adverse drug reactions.
Two double blind randomised trials showed statistically significant drug placebo differences for each of the two primary outcome measures (ADAS-cog and CIBIC plus). ADAS-cog examines cognitive performance - including memory, orientation, attention, reason, language and praxis. The CIBIC Plus is a global measure of change in patient functionality that is derived through evaluation of four major areas of functioning (general, cognition, behaviour and activities of daily living). The analyses of secondary efficacy variables (MMSE, CDR-SB) support the results of the primary efficacy analyses.

5.3 Preclinical Safety Data

Genotoxicity.

Donepezil was not mutagenic in reverse mutation assays in bacteria or in the mouse lymphoma forward mutation assay in vitro. Donepezil did not induce unscheduled DNA synthesis in rat primary hepatocyte cultures following oral dosing of the animals. In the chromosome aberration test in cultures of Chinese hamster lung cells, some clastogenic effects were observed. Donepezil was not clastogenic in the in vivo mouse micronucleus test.

Carcinogenicity.

No evidence of carcinogenicity was found in long-term studies in mice and rats with dietary dosing of donepezil resulting in peak plasma concentrations of up to 17 times and 6-19 times, respectively, that in humans at the recommended clinical dose of 10 mg/day.

6 Pharmaceutical Particulars

6.1 List of Excipients

The inactive ingredients are lactose monohydrate, maize starch, microcrystalline cellulose, hyprolose and sodium stearylfumarate. The film coating contains purified talc, macrogol 6000, hypromellose and titanium dioxide. Additionally, the 10 mg tablet contains iron oxide yellow as a colouring agent.

6.2 Incompatibilities

Incompatibilities were either not assessed or not identified as part of the registration of this medicine.

6.3 Shelf Life

In Australia, information on the shelf life can be found on the public summary of the Australian Register of Therapeutic Goods (ARTG). The expiry date can be found on the packaging.

6.4 Special Precautions for Storage

Store below 30°C. Store in original container.

6.5 Nature and Contents of Container

Donepezil GH film-coated tablets, containing either 5 mg or 10 mg donepezil hydrochloride (as monohydrate), are packaged in PVC/PVDC/Al blister packs of 28 tablets.
* Non-marketed pack sizes: 14, 30, 50, 56, 60, 84, 98, 112, 120.

6.6 Special Precautions for Disposal

In Australia, any unused medicine or waste material should be disposed of by taking to your local pharmacy.

6.7 Physicochemical Properties

Donepezil hydrochloride is a white crystalline powder and is freely soluble in chloroform, soluble in water and in glacial acetic acid, slightly soluble in ethanol and in acetonitrile and practically insoluble in ethyl acetate and in n-hexane.
Donepezil [donepezil hydrochloride (as monohydrate)] is a specific and reversible inhibitor of the enzyme acetylcholinesterase.

Chemical structure.


Chemical Name: (RS)-1-benzyl-4- [5,6-dimethoxy-1 -indanon)-2-yl] methylpiperidine hydrochloride, monohydrate.
Molecular Formula: C24H29NO3.HCl.H2O.
Molecular Weight: 433.98.

CAS number.

884740-09-4.

7 Medicine Schedule (Poisons Standard)

Prescription only medicine (S4).

Summary Table of Changes