Consumer medicine information

Dexmedetomidine-Teva

Dexmedetomidine hydrochloride

BRAND INFORMATION

Brand name

Dexmedetomidine-Teva

Active ingredient

Dexmedetomidine hydrochloride

Schedule

What is in this leaflet

This leaflet answers some common questions about Dexmedetomidine.

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 Dexmedetomidine 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. You may need to read it again.

What Dexmedetomidine is used for

Intensive Care Sedation

Dexmedetomidine can be used as a sedative (calming agent) if adults need to be calm or sleepy in the Intensive Care Unit whilst they are being ventilated (on a breathing machine). It may be given as an infusion up to 24 hours.

Procedural Sedation

Dexmedetomidine can be given to adults prior to an operation if they are not on a ventilator (breathing machine) if it is required for the procedure or surgery that they be sleepy and calm.

This medicine belongs to a group of medicines called alpha-2-receptor agonists. This medicine works by its actions on brain chemicals.

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.

Dexmedetomidine is only available with a doctor's prescription.

Before you are given Dexmedetomidine

When you must not take it

Do not take Dexmedetomidine if you have an allergy to:

any medicine containing dexmedetomidine hydrochloride
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 if you are pregnant. It may affect your developing baby if you take it during pregnancy.

Do not breast-feed if you are taking this medicine. The active ingredient in this medicine passes into breast milk and there is a possibility that your baby may be affected.

Do not give this medicine to a child under the age of 18 years. Safety and effectiveness in children younger than 18 years have not been established.

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 start taking this medicine, 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 have or have had any of the following medical conditions:

cardiovascular disease
diabetes

Elderly patients greater than 65 years old may be more prone to the blood pressure lowering effects of Dexmedetomidine.

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 him/her before you start taking Dexmedetomidine.

Taking other medicines

Tell your doctor or pharmacist if you are taking any other medicines, including any that you get without a prescription from your pharmacy, supermarket or health food shop.

Some medicines and Dexmedetomidine may interfere with each other. These include:

medicines used to produce calmness or to help you sleep
strong pain relievers

These medicines may be affected by Dexmedetomidine 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 and pharmacist have more information on medicines to be careful with or avoid while taking this medicine.

How to take Dexmedetomidine

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

How much to take

Your doctor will decide what dose you will receive. This depends on your condition and other factors such as your weight. The dose will be adjusted to keep you at the right depth of sleep or sedation.

How it is given

Dexmedetomidine is given by a slow injection (drip) into a vein.

Dexmedetomidine should only be given by a doctor or nurse.

If you take too much (overdose)

As Dexmedetomidine is given to you under the supervision of your doctor, it is very unlikely that you will receive too much.

Symptoms of an overdose may include extreme drowsiness, confusion, dizziness, weakness or becoming unconscious.

While you are using Dexmedetomidine

Things you must do

Tell any other 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.

If you are about to have any blood tests, tell your doctor that you are taking this medicine. It may interfere with the results of some tests.

Things you must not do

Do not take Dexmedetomidine to treat any other complaints unless your doctor tells you to.

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

Things to be careful of

Be careful driving or operating machinery until you know how Dexmedetomidine affects you. This medicine may cause (dizziness, light-headedness, tiredness, drowsiness, and therefore affect alertness in some people. If you have any of these symptoms, do not drive, operate machinery or do anything else that could be dangerous. Ask your doctor when you can return to work involving driving or operating machinery or heavy equipment.

If you feel light-headed, dizzy or faint when getting out of bed or standing up, get up slowly. Standing up slowly, especially when you get up from bed or chairs, will help your body get used to the change in position and blood pressure. If this problem continues or gets worse, talk to your doctor.

Side effects

Tell your doctor or pharmacist as soon as possible if you do not feel well while you are taking Dexmedetomidine.

This medicine helps provide sedation for most people but it may have unwanted side effects in a few people. 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.

If you are over 65 years of age you may have an increased chance of getting side effects.

Do not be alarmed by the following lists 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 or pharmacist if you notice any of the following and they worry you:

dizziness
light-headedness
nausea and/or vomiting
high temperature
dry mouth

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

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

changes in heart rate including slowing or quickening of heart beat

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 that is making you feel unwell.

Other side effects not listed above may also occur in some people.

After using Dexmedetomidine

Storage

Dexmedetomidine-Teva will be stored in the pharmacy or kept on the ward. The injection is kept in a cool dry place where the temperature stays below 25°C.

Product description

What it looks like

Dexmedetomidine-Teva is a clear, colourless solution. It is available in 2 mL glass vials.

Ingredients

Dexmedetomidine-Teva contains 118 micrograms/mL of dexmedetomidine hydrochloride (equivalent to 100 micrograms/mL dexmedetomidine base) as the active ingredient.

It also contains:

sodium chloride
water for injections

This medicine does not contain lactose, sucrose, gluten, tartrazine or any other azo dyes.

Sponsor

Australian Sponsor:

Teva Pharma Australia Pty Ltd
Macquarie Park NSW 2113
AUST R 290530

New Zealand Sponsor:

Teva Pharma (New Zealand) Limited
Auckland 1541

This leaflet was prepared in August 2018.

® = Registered Trademark

Published by MIMS May 2019

BRAND INFORMATION

Brand name

Dexmedetomidine-Teva

Active ingredient

Dexmedetomidine hydrochloride

Schedule

1 Name of Medicine

Dexmedetomidine hydrochloride.

2 Qualitative and Quantitative Composition

Dexmedetomidine-Teva is a sterile, non-pyrogenic solution suitable for intravenous infusion.
Dexmedetomidine hydrochloride is a white or almost white powder, freely soluble in water and its pKa is 7.1. The partition coefficient in octanol: water at pH 7.84 is 2.89. Each 2 mL of Dexmedetomidine-Teva contains 236 micrograms of dexmedetomidine HCl (equivalent to 200 micrograms dexmedetomidine base) and 18 mg of sodium chloride in water for injections. The solution is preservative-free and contains no additives or chemical stabilisers.

3 Pharmaceutical Form

Dexmedetomidine-Teva dexmedetomidine (as hydrochloride) concentrated injection 200 micrograms/2 mL is supplied as clear, colourless, isotonic solution with a pH of 4.5 to 7.0. Dexmedetomidine-Teva is presented in a 3 mL vial, and must be diluted prior to use.

4 Clinical Particulars

4.1 Therapeutic Indications

ICU sedation.

For sedation of initially intubated patients during treatment in an intensive care setting. The use of dexmedetomidine by continuous infusion in these patients should not exceed 24 hours.

Procedural sedation.

For sedation of non-intubated patients prior to and/or during surgical and other procedures.

4.2 Dose and Method of Administration

Note.

Dexmedetomidine should be administered only by persons skilled in anaesthetics or in the management of patients in the intensive care setting. Due to the known pharmacological effects, patients should be continuously monitored.
Contains no antimicrobial agent. For single use in one patient only. Discard any residue after use.
Clinically significant events of bradycardia and sinus arrest have been associated with dexmedetomidine hydrochloride administration in young, healthy volunteers with high vagal tone or with different routes of administration including rapid intravenous or bolus administration of dexmedetomidine hydrochloride.

Adults.

Dexmedetomidine should be individualised and titrated to the desired clinical effect.

ICU sedation.

Initiation.

For adult patients, Dexmedetomidine-Teva may be initiated with a loading infusion of 1 (one) microgram/kg over 10 to 20 minutes, if needed. The use of Dexmedetomidine-Teva by continuous infusion in these patients should not exceed 24 hours.
The use of loading dose of dexmedetomidine was associated with an increased rate of adverse event, including hypotension, hypertension and bradycardia, in clinical trials involving adult ICU patients.
For patients being converted from alternate sedative therapy a loading dose may not be required.

Maintenance of ICU sedation.

Adult patients will generally require a maintenance infusion of 0.2 to 1 microgram/kg/hr*. The rate of the maintenance infusion should be adjusted to achieve the desired level of sedation. As a guide, it is recommended that 0.4 microgram/kg/hr should be the initial maintenance infusion. If after approximately 5 minutes sedation is not adequate, the rate of infusion can be increased in increments of 0.1 microgram/kg/hr or higher. Dosages as low as 0.05 microgram/kg/hr have been used in clinical studies. Patients receiving Dexmedetomidine-Teva have been observed to be rousable and alert when stimulated. This is an expected component of Dexmedetomidine-Teva sedation and should not be considered a lack of efficacy in the absence of other clinical signs and symptoms.
*A dose reduction for both the loading and maintenance infusions should be considered in patients with impaired hepatic function and in patients over 65 years of age.
Dexmedetomidine has been continuously infused in mechanically ventilated patients prior to extubation, during extubation, and post-extubation. It is not necessary to discontinue Dexmedetomidine-Teva prior to extubation.

Procedural sedation.

Based on sedation scores, the loading infusion provides clinically effective onset of sedation 10 to 15 minutes after start of infusion.

Initiation.

For adult patients, Dexmedetomidine-Teva is generally initiated with a loading infusion of 1 (one) microgram/kg over 10 to 20 minutes for sedation of non-intubated patients undergoing surgical and other procedures, as well as, for initiation of awake fibreoptic intubation.
For patients with impaired hepatic function and in patients over 65 years of age, the loading dose may be omitted or reduced, e.g. 0.5 microgram/kg over 10 minutes may be suitable.
For patients undergoing less invasive procedures, such as ophthalmic surgery, the loading dose may be reduced, e.g. 0.5 micrograms/kg over 10 minutes may be suitable.

Maintenance of procedural sedation.

Following the load, maintenance dosing of Dexmedetomidine-Teva should generally be initiated at 0.6 microgram/kg/hr and titrated to achieve desired clinical effect with doses ranging from 0.2 to 1 microgram/kg/hr for all procedures. The rate of the maintenance infusion should be adjusted to achieve the targeted level of sedation.
Following the load in awake fibreoptic intubation, a fixed maintenance dose of 0.7 microgram/kg/hr should be used.
A dose reduction should be considered in patients with impaired hepatic function and in patients over 65 years of age.

Children.

Safety and efficacy of dexmedetomidine has not been studied in children.

Administration.

A controlled infusion device should be used to administer dexmedetomidine.
Strict aseptic technique must always be maintained during handling of dexmedetomidine infusion.

Preparation.

Preparation of infusion solutions is the same, whether for the loading dose or maintenance.
To prepare the infusion, withdraw 2 mL of dexmedetomidine (as hydrochloride) concentrated injection and add to 48 mL of 0.9% sodium chloride to total 50 mL. Shake gently to mix well. Use as soon as practicable after dilution to reduce microbiological hazard. If storage is necessary, hold at 2-8°C for not more than 24 hours. Parenteral products should be inspected visually for particulate matter and discolouration prior to administration.
Vials are intended for single patient use only.

Compatibility.

Dexmedetomidine has been shown to be compatible when administered with the following intravenous fluids: lactated ringers, 5% glucose in water, 0.9% sodium chloride in water, 20% mannitol in water.
Dexmedetomidine has been found to be compatible with water solutions of the following drugs when administered via Y-site injection: thiopental sodium, vecuronium bromide, pancuronium bromide, glycopyrrolate, phenylephrine hydrochloride.

4.3 Contraindications

Dexmedetomidine hydrochloride is contraindicated in patients with a known hypersensitivity to dexmedetomidine.

4.4 Special Warnings and Precautions for Use

Drug administration.

Dexmedetomidine-Teva should be administered only by persons skilled in the management of patients in the intensive care or operating room setting. Continuous electrocardiogram (ECG), blood pressure, and oxygen saturation monitoring are recommended during infusion of dexmedetomidine. Dexmedetomidine may cause reduced lacrimation. Lubrication of the patient's eyes should be considered when administering dexmedetomidine to avoid corneal dryness.
Dexmedetomidine is only to be used for procedural sedation with the provision of appropriate monitoring and under the constant supervision of an appropriately trained medical practitioner.
Although dexmedetomidine has sedative effects it has not been shown to be amnestic. Should amnesia be desired during procedural sedation then a drug with amnestic properties (such as a benzodiazepine) should be co-administered.

Hypotension, bradycardia and sinus arrest.

Clinical events of bradycardia and sinus arrest have been associated with dexmedetomidine administration in young, healthy volunteers with high vagal tone or with different routes of administration including rapid intravenous or bolus administration of dexmedetomidine.
Decreased blood pressure and/or heart rate may occur with the administration of dexmedetomidine. Dexmedetomidine decreases sympathetic nervous activity and therefore, these effects may be expected to be most pronounced in patients with desensitised autonomic nervous system control (i.e. ageing, diabetes, chronic hypertension, severe cardiac disease).
Reports of hypotension and bradycardia have been associated with dexmedetomidine infusion. If medical intervention is required, treatment may include decreasing or stopping the infusion of dexmedetomidine increasing the rate of IV fluid administration, elevation of the lower extremities, and use of pressor agents. Because dexmedetomidine has the potential to augment bradycardia induced by vagal stimuli, clinicians should be prepared to intervene. The intravenous administration of anticholinergic agents (e.g. glycopyrrolate, atropine) should be considered to modify vagal tone. In clinical trials, glycopyrrolate or atropine were effective in the treatment of most episodes of dexmedetomidine induced bradycardia. However, in some patients with significant cardiovascular dysfunction, more advanced resuscitative measures were required.
Caution should be exercised when administering dexmedetomidine to patients with advanced heart block and/or severe ventricular dysfunction. Because dexmedetomidine decreases sympathetic nervous system activity, hypotension and/or bradycardia may be expected to be more pronounced in hypovolaemic patients and in those with diabetes mellitus or chronic hypertension and in elderly patients.
In situations where other vasodilators or negative chronotropic agents are administered, co-administration of dexmedetomidine could have an additive pharmacodynamic effect and should be administered with caution.
Clinical events of bradycardia or hypotension may be potentiated when dexmedetomidine is used concurrently with propofol or midazolam. Therefore, consider a reduction in the dose of midazolam or propofol.
Elderly patients over 65 years of age, or diabetic patients, are more prone to hypotension with the administration of dexmedetomidine. All episodes either spontaneously reversed or were treated with standard therapy.

Transient hypertension.

Transient hypertension has been observed primarily during the loading infusion, associated with initial peripheral vasoconstrictive effects of dexmedetomidine and relatively higher plasma concentrations achieved during the loading infusion. If intervention is necessary, reduction of the loading infusion rate may be considered. Following the loading infusion, the central effects of dexmedetomidine dominate and the blood pressure usually decreases.

Withdrawal.

Although not specifically studied, if dexmedetomidine is administered chronically and stopped abruptly, withdrawal symptoms similar to those reported for another alpha-2-adrenergic agent, clonidine, may result. These symptoms include nervousness, agitation, and headaches, accompanied or followed by a rapid rise in blood pressure and elevated catecholamine concentrations in the plasma. Dexmedetomidine should not be administered for greater than 24 hours.

Procedural sedation.

Withdrawal symptoms were not seen after discontinuation of short term infusions of dexmedetomidine (< 6 hrs).

Adrenal insufficiency.

Dexmedetomidine had no effect on ACTH-stimulated cortisol release in dogs after a single dose; however, after the subcutaneous infusion of dexmedetomidine for one week, the cortisol response to ACTH was diminished by approximately 40%.
In a clinical study, prolonged infusions of dexmedetomidine at doses up to 1.4 microgram/kg/hr were not associated with significant adrenocortical suppression.

Hyperthermia.

Dexmedetomidine may induce hyperthermia that may be resistant to traditional cooling methods. Dexmedetomidine treatment should be discontinued in the event of a sustained unexplained fever and is not recommended for use in malignant hyperthermia-sensitive patients.

Use in hepatic impairment.

Since dexmedetomidine clearance decreases with increasing severity of hepatic impairment, dose reductions should be considered in patients with impaired hepatic function (see Section 4.2 Dose and Method of Administration).

Use in the elderly.

Dexmedetomidine is known to be substantially excreted by the kidney, and the risk of adverse reactions to this drug may be greater in patients with impaired renal function. Because elderly patients are more likely to have decreased renal function, care should be taken in dose selection in elderly patients, and it may be useful to monitor renal function.

ICU sedation.

A total of 729 patients in the clinical studies were 65 years of age and over. A total of 200 patients were 75 years of age and over. In patients greater than 65 years of age, a higher incidence of bradycardia and hypotension was observed following administration of dexmedetomidine (see Section 4.4 Special Warnings and Precautions for Use).
Consideration should be given to lower initial loading and maintenance doses in patients > 65 years and careful monitoring for the development of hypotension when up titrating the maintenance dose (see Section 4.2 Dose and Method of Administration).

* Procedural sedation.

A total of 131 patients in the clinical studies were 65 years of age and over. A total of 47 patients were 75 years of age and over. Hypotension occurred at a higher incidence in dexmedetomidine-treated patients 65 years or older (71.9%) and 75 years or older (73.5%) as compared to patients < 65 years (46.8%). The loading dose may be omitted or reduced and a reduction in the maintenance infusion should be considered for patients greater than 65 years of age (see Section 4.2 Dose and Method of Administration).

Paediatric use.

Safety and efficacy of dexmedetomidine in children below 18 years of age have not been studied.

Effects on laboratory tests.

No data available.

4.5 Interactions with Other Medicines and Other Forms of Interactions

General.

In vitro studies indicate that clinically relevant cytochrome P450 mediated drug interactions are unlikely.

Anaesthetics/ sedatives/ hypnotics/ opioids.

Co-administration of dexmedetomidine hydrochloride is likely to lead to an enhancement of effects with anaesthetics, sedatives, hypnotics, and opioids. Specific studies have confirmed these effects with sevoflurane, isoflurane, propofol, alfentanil, and midazolam. No pharmacokinetic interactions between dexmedetomidine and isoflurane, propofol, alfentanil, and midazolam were demonstrated. However, due to pharmacodynamic effects, when co-administered with dexmedetomidine hydrochloride, a reduction in dosage with these agents may be required.

Neuromuscular blockers.

No clinically meaningful increases in the magnitude of neuromuscular blockade and no pharmacokinetic interactions were observed with dexmedetomidine hydrochloride and rocuronium administration.

4.6 Fertility, Pregnancy and Lactation

Effects on fertility.

Dexmedetomidine did not affect reproductive capacity or fertility in male or female rats after daily subcutaneous injections at doses up to 54 microgram/kg/day for 10 weeks prior to mating in males and 3 weeks prior to mating and during mating in females. Systemic exposure (AUC_{0-24 h}) at this dose level was less than anticipated at the maximum recommended human dose of 17.8 microgram/kg.
(Category B1¹)
Radiolabelled dexmedetomidine administered subcutaneously to female rats on gestation day 18 crossed the placental barrier to foetal tissue.
Teratogenic effects were not observed following administration of dexmedetomidine at subcutaneous doses up to 200 microgram/kg/day in rats or IV doses up to 96 microgram/kg/day in rabbits. Systemic exposure (AUC_{1-24 h}) at these dose levels was 3 to 5 times greater than those in humans at the maximum recommended dose of 17.8 microgram/kg. In rats, foetal and pup body weights were reduced at SC doses ≥ 6 microgram/kg/day, post-implantation loss was increased at 200 microgram/kg/day, and perinatal mortality was increased at SC doses ≥ 18 microgram/kg/day. These findings are consistent with those of clonidine, another alpha₂-adrenoreceptor agonist. Dexmedetomidine has no effect on foetal body weight or embryofoetal viability at IV doses as high as 96 microgram/kg/day in rabbits. Dexmedetomidine also produced delayed motor development in rat pups at a dose of 32 microgram/kg (less than the maximum recommended human intravenous dose). No such effects were observed at a dose of 2 microgram/kg.
There are no adequate and well-controlled studies in pregnant women. Dexmedetomidine should be used during pregnancy only if the potential benefits justify the potential risk to the foetus.

Labour and delivery.

The safety of dexmedetomidine in labour and delivery has not been studied and is, therefore, not recommended for obstetrics, including caesarean section deliveries.
¹ Category B1: drugs which have been taken by only a limited number of pregnant women and women of childbearing age, without an increase in the frequency of malformation or other direct or indirect harmful effects in the human foetus having been observed. Studies in animals have not shown evidence of an increased occurrence of foetal damage.
It is not known whether dexmedetomidine is excreted in human milk. Because many drugs are excreted in human milk, caution should be exercised when dexmedetomidine infusion is administered to a nursing woman. Radiolabelled dexmedetomidine administered subcutaneously to lactating female rats was distributed to, but did not accumulate in milk.

4.7 Effects on Ability to Drive and Use Machines

The effects of this medicine on a person's ability to drive and use machines were not assessed as part of its registration.

4.8 Adverse Effects (Undesirable Effects)

ICU sedation.

Adverse event information derived from the placebo-controlled, continuous infusion trials of dexmedetomidine for sedation in the surgical ICU setting in which 387 patients received dexmedetomidine. In these studies, the mean total dose was 7.06 microgram/kg (SD = 2.86), mean dose per hour was 0.51 microgram/kg/hr (SD = 0.39) and the mean duration of infusion of 15.6 hours (range: 0.17 to 29.08). The population was between 19 to 83 years of age, 43% > 65 years of age, 73% male and 97% Caucasian. Overall, the most frequently observed treatment-emergent adverse events included hypotension, hypertension, nausea, bradycardia, fever, vomiting, hypoxia, tachycardia and anaemia (see Table 1).

Adverse event information derived from the midazolam-controlled, continuous infusion trial of dexmedetomidine for sedation in a predominantly medical ICU setting in which 244 patients received dexmedetomidine for long-term sedation. Treatment-emergent adverse events occurring at an incidence of > 5% are provided in Table 2. The mean total dose was 72.5 microgram/kg (range: 0.1 to 489.9), mean dose per hour was 0.83 microgram/kg/hr (range: 0.18 to 1.54) and the mean duration of infusion of 3.4 days (range: 0.02 to 15.6). The population was between 18 to 89 years of age, 46% > 65 years of age, 51% male and 79% Caucasian. The most frequent adverse events for this population were hypotension, tachycardia, bradycardia and systolic hypertension (see Section 4.4 Special Warnings and Precautions for Use).

* The following adverse events occurred between 2 and 5% for dexmedetomidine and midazolam, respectively: anaemia (2.9%, 4.1%), thrombocytopaenia (0.8%, 2.5%), atrial fibrillation (2.0%, 3.3%), abdominal distension (4.1%, 1.6%), abdominal pain (1.2%, 3.3%), diarrhoea (4.9%, 4.1%), nausea (4.1%, 1.6%), vomiting (2.0%, 4.9%), peripheral oedema (4.1%, 4.9%), pneumonia (1.2%, 4.9%), sepsis (2.5%, 2.5%), septic shock (1.6%, 2.5%), urinary tract infection (0, 3.3%), haemoglobin decreased (0, 2.5%), urine output decreased (2.0%, 3.3%), electrolyte imbalance (0.8%, 2.5%), fluid overload (1.6%, 4.1%), hypernatraemia (2.5%, 1.6%), hypophosphataemia (2.5%, 1.6%), headache (2.0%, 0.8%), anxiety (2.5%, 0), oliguria (0.4%, 2.5%), renal failure acute (2.5%, 0.8%), acute respiratory distress syndrome (2.5%, 0.8%), pharyngolaryngeal pain (2.5%, 4.9%), pleural effusion (2.9%, 2.5%), respiratory failure (4.5%, 3.3%), decubitus ulcer (1.2%, 4.9%), and rash (0.8%, 2.5%).

Procedural sedation.

Adverse event information is derived from the two primary phase 3 trials for procedural sedation in which 318 patients received dexmedetomidine. The mean total dose was 1.6 microgram/kg (range: 0.5 to 6.7), mean dose per hour was 1.3 microgram/kg/hr (range: 0.3 to 6.1) and the mean duration of infusion of 1.5 hours (range: 0.1 to 6.2). The population was between 18 to 93 years of age, 30% > 65 years of age, 52% male and 61% Caucasian.
Treatment-emergent adverse events occurring at an incidence of > 2% are provided in Table 3. The majority of the adverse events were assessed as mild in severity. The most frequent adverse events were hypotension, bradycardia, and dry mouth. Pre-specified criteria for the vital signs to be reported as Adverse Events are footnoted below the table. Respiratory depression and hypoxia was similar in the dexmedetomidine and placebo groups when evaluated against the pre-specified criteria. The incidence of absolute respiratory depression and hypoxia was less in the dexmedetomidine-treated patients than the placebo patients (3.04% vs 12.7%) in the MAC trial.

Post-marketing experience.

The adverse reactions that have been identified during post approval use of dexmedetomidine are provided in Table 4. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure.
Hypotension and bradycardia were the most common adverse reactions associated with the use of dexmedetomidine during post approval use of the drug.

Dependence.

The dependence potential of dexmedetomidine has not been studied in humans.

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

The tolerability of dexmedetomidine was noted in one study in which healthy subjects achieved plasma concentrations from 1.8 up to 13 times the upper boundary of the therapeutic range. The most notable effects observed in two subjects who achieved the highest plasma concentrations were 1st degree AV block and 2nd degree heart block. No haemodynamic compromise was noted with the AV block and the heart block resolved spontaneously within one minute.
Of five patients reported with overdose of dexmedetomidine in the Phase II/III ICU sedation studies, two had no symptoms reported; one patient received a 2 microgram/kg loading dose over 10 minutes (twice the recommended loading dose) and one patient received a maintenance infusion of 0.8 microgram/kg/hr. Two other patients who received a 2 microgram/kg loading dose over 10 minutes experienced bradycardia with or without hypotension. One patient, who received a loading bolus dose of undiluted (100 microgram/mL) dexmedetomidine (19.4 microgram/kg), had cardiac arrest from which he was successfully resuscitated.
The most common adverse effects reported in conjunction with overdose include bradycardia, hypotension, hypertension, over sedation, respiratory depression and cardiac arrest.
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.

Dexmedetomidine is a relatively selective alpha₂-adrenoreceptor agonist with a broad range of pharmacologic properties.
The sedative actions of dexmedetomidine are believed to be mediated primarily by post-synaptic alpha₂-adrenoreceptors, which in turn act on inhibitory pertussis-toxin-sensitive G protein, thereby increasing conductance through potassium channels. The site of the sedative effects of dexmedetomidine has been attributed to the locus coeruleus. The analgesic actions are believed to be mediated by a similar mechanism of action at the brain and spinal cord level.
Alpha₂-selectivity was observed in animals following slow intravenous (IV) infusion of low and medium doses (10-300 microgram/kg). Both alpha₁ and alpha₂ activity was observed following slow IV infusion of high doses (≥ 1000 microgram/kg) or with rapid IV administration. Dexmedetomidine has a low affinity for beta adrenergic, muscarinic, dopaminergic and serotonin receptors.

Clinical trials.

ICU sedation.

Two randomised, double-blind, parallel-group, placebo-controlled multicentre clinical trials in a surgical intensive care unit (ICU) 754 patients being treated. All patients were initially intubated and received mechanical ventilation.
Two of these trials evaluated the sedative properties of dexmedetomidine by comparing the amount of rescue medication (midazolam in one trial and propofol in the second) required to achieve a specified level of sedation (using the standardised Ramsay sedation scale) between dexmedetomidine and placebo from onset of treatment to extubation or to a total treatment duration of 24 hours. The Ramsay Level of Sedation Scale is displayed in Table 5.

In the first study, 175 patients were randomised to receive placebo and 178 to receive dexmedetomidine by intravenous infusion at a dose of 0.4 microgram/kg/hr (with allowed adjustment between 0.2 and 0.7 microgram/kg/hr) following an initial loading infusion of 1 (one) microgram/kg IV over 10 minutes. The study drug infusion rate was adjusted to maintain a Ramsay sedation score of ≥ 3. Patients were allowed to receive "rescue" midazolam as needed to augment the study drug infusion. In addition, morphine sulfate was administered for pain as needed. The primary outcome measure for this study was the total amount of rescue medication (midazolam) needed to maintain sedation as specified while intubated. Patients randomised to placebo received significantly more midazolam than patients randomised to dexmedetomidine (see Table 6).
A second prospective primary analysis assessed the sedative effects of dexmedetomidine by comparing the percentage of patients who achieved a Ramsay sedation score of ≥ 3 during intubation without the use of additional rescue medication. A significantly greater percentage of patients in the dexmedetomidine group maintained a Ramsay sedation score of ≥ 3 without receiving any midazolam rescue compared to the placebo group (see Table 6).

A prospective secondary analysis assessed the dose of morphine sulfate administered to patients in the dexmedetomidine and placebo groups. On average, dexmedetomidine-treated patients received less morphine sulfate for pain than placebo-treated patients (0.47 versus 0.83 mg/h). In addition, 44% (79 of 178 patients) of dexmedetomidine patients received no morphine sulfate for pain versus 19% (33 of 175 patients) in the placebo group.
In the second study, 198 patients were randomised to receive placebo and 203 to receive dexmedetomidine by intravenous infusion at a dose of 0.4 microgram/kg/hr (with allowed adjustment between 0.2 and 0.7 microgram/kg/hr) following an initial loading infusion of 1 (one) microgram/kg IV over 10 minutes. The study drug infusion was adjusted to maintain a Ramsay sedation score of ≥ 3. Patients were allowed to receive "rescue" propofol as needed to augment the study drug infusion. In addition, morphine sulfate was administered as needed for pain. The primary outcome measure for this study was the total amount of rescue medication (propofol) needed to maintain sedation as specified while intubated.
Patients randomised to placebo received significantly more propofol than patients randomised to dexmedetomidine (see Table 7).
A significantly greater percentage of patients in the dexmedetomidine group compared to the placebo group maintained a Ramsay sedation score of ≥ 3 without receiving any propofol rescue (see Table 7).

Procedural sedation.

The safety and efficacy of dexmedetomidine for sedation of non-intubated patients prior to and/or during surgical and other procedures was evaluated in two randomised, double-blind, placebo-controlled multicentre clinical trials. Study 1 evaluated the sedative properties of dexmedetomidine in patients having a variety of elective surgeries/procedures performed under monitored anaesthesia care. Study 2 evaluated dexmedetomidine in patients undergoing awake fibreoptic intubation (AFOI) prior to a surgical or diagnostic procedure.
In Study 1, the sedative properties of dexmedetomidine were evaluated by comparing the percent of patients not requiring rescue midazolam to achieve a specified level of sedation using the standardised Observer's Assessment of Alertness/Sedation Scale between dexmedetomidine and placebo. The Observer's Assessment of Alertness/Sedation Scale (Table 8).

Patients were randomised to receive a dexmedetomidine loading infusion of either dexmedetomidine 1 microgram/kg or dexmedetomidine 0.5 microgram/kg, or placebo (normal saline) given over 10 minutes and followed by a maintenance infusion started at 0.6 microgram/kg/hr. The maintenance infusion of study drug could be titrated from 0.2 microgram/kg/hr to 1 microgram/kg/hr to achieve the targeted sedation score (OAA/S ≤ 4). Patients were allowed to receive rescue midazolam as needed to achieve and/or maintain an OAA/S < 4. After achieving the desired level of sedation, a local or regional anaesthetic block was performed. Demographic characteristics were similar between the dexmedetomidine and placebo groups. Efficacy results showed that dexmedetomidine was significantly more effective than placebo when used to sedate non-intubated patients requiring monitored anaesthesia care during surgical and other procedures (Table 9).
In Study 2, the sedative properties of dexmedetomidine were evaluated by comparing the percent of patients requiring rescue midazolam to achieve or maintain a specified level of sedation using the Ramsay Sedation Scale score > 2 (Table 5) during AFOI. Patients were randomised to receive a dexmedetomidine loading infusion of 1 microgram/kg or placebo (normal saline) given over 10 minutes followed by a fixed maintenance infusion of 0.7 microgram/kg/hr. After achieving the desired level of sedation, topicalisation of the airway occurred. Patients were allowed to receive rescue midazolam as needed to achieve and/or maintain an RSS > 2. Demographic characteristics were similar between the dexmedetomidine and placebo groups.

5.2 Pharmacokinetic Properties

Following intravenous administration, dexmedetomidine exhibits the following pharmacokinetic characteristics: rapid distribution phase with a distribution half-life (t_1/2) of about six minutes; terminal elimination half-life (t_1/2) approximately two hours; steady-state volume of distribution (V_ss) approximately 118 litres. Clearance (CL) has an estimated value of about 39 L/h. The mean body weight associated with this clearance estimate was 72 kg.
Dexmedetomidine exhibits linear kinetics in the dosage range of 0.2 to 0.7 microgram/kg/hr when administered by IV infusion for up to 24 hours. Table 10 shows the main pharmacokinetic parameters when dexmedetomidine was infused (after appropriate loading doses) at maintenance infusion rates of 0.17 microgram/kg/hr (target concentration of 0.3 nanogram/mL) for 12 and 24 hours, 0.33 microgram/kg/hr (target concentration of 0.6 nanogram/mL) for 24 hours, and 0.70 microgram/kg/hr (target concentration of 1.25 nanogram/mL) for 24 hours.

Distribution.

The steady-state volume of distribution (V_ss) of dexmedetomidine is approximately 118 liters. Dexmedetomidine protein binding was assessed in the plasma of normal healthy male and female volunteers. The average protein binding was 94% and was constant across the different concentrations tested. Protein binding was similar in males and females. The fraction of dexmedetomidine that was bound to plasma proteins was statistically significantly decreased in subjects with hepatic impairment compared to healthy subjects. The potential for protein binding displacement of dexmedetomidine by fentanyl, ketorolac, theophylline, digoxin and lidocaine was explored in vitro, and negligible changes in the plasma protein binding of dexmedetomidine were observed. The potential for protein binding displacement of phenytoin, warfarin, ibuprofen, propranolol, theophylline and digoxin by dexmedetomidine was explored in vitro and none of these compounds appeared to be significantly displaced by dexmedetomidine.

Metabolism.

Dexmedetomidine undergoes almost complete biotransformation with very little unchanged dexmedetomidine excreted in urine and faeces. Biotransformation involves both direct glucuronidation as well as cytochrome P450 mediated metabolism. The major metabolic pathways of dexmedetomidine are: direct N-glucuronidation to inactive metabolites; aliphatic hydroxylation (mediated primarily by CYP2A6) of dexmedetomidine to generate 3-hydroxydexmedetomidine, the glucuronide of 3-hydroxydexmedetomidine, and 3-carboxydexmedetomidine; and N-methylation of dexmedetomidine to generate 3-hydroxy-N-methyldexmedetomidine, 3-carboxy-N-methyldexmedetomidine, and N-methyldexmedetomidine-O-glucuronide.

Excretion.

The terminal elimination half-life (t_1/2) of dexmedetomidine is approximately 2 hours and clearance is estimated to be approximately 39 L/h. A mass balance study demonstrated that after nine days an average of 95% of the radioactivity, following IV administration of radiolabeled dexmedetomidine, was recovered in the urine and 4% in the faeces. No unchanged dexmedetomidine was detected in the urine. Approximately 85% of the radioactivity recovered in the urine was excreted within 24 hours after the infusion. Fractionation of the radioactivity excreted in urine demonstrated that products of N-glucuronidation accounted for approximately 34% of the cumulative urinary excretion. In addition, aliphatic hydroxylation of parent drug to form 3-hydroxydexmedetomidine, the glucuronide of 3-hydroxydexmedetomidine, and 3-carboxydexmedetomidine together represented approximately 14% of the dose in urine. N-methylation of dexmedetomidine to form 3-hydroxy-N-methyldexmedetomidine, 3-carboxy-N-methyldexmedetomidine, and N-methyldexmedetomidine-O-glucuronide accounted for approximately 18% of the dose in urine. The N-methyl metabolite itself was a minor circulating component and was undetected in urine. Approximately 28% of the urinary metabolites have not been identified.

Hepatic impairment.

In subjects with varying degrees of hepatic impairment (Child-Pugh Class A, B, or C), clearance values were lower than in healthy subjects. The mean clearance values for subjects with mild, moderate, and severe hepatic impairment were 74%, 64% and 53%, of those observed in the normal healthy subjects, respectively. Mean clearances for free drug were 59%, 51% and 32% of those observed in the normal healthy subjects, respectively.
Although dexmedetomidine hydrochloride is dosed to effect, it may be necessary to consider dose reduction depending on the degree of hepatic impairment (see Section 4.2 Dose and Method of Administration).

Renal impairment.

Dexmedetomidine hydrochloride pharmacokinetics (C_max, T_max, AUC, t_1/2, CL, and V_ss) were not different in subjects with severe renal impairment (CrCl: < 30 mL/min) compared to healthy subjects.
In view of the limited toxicological data and the potential for higher plasma metabolite concentrations in patients with severe renal impairment, caution is advised with prolonged dosing in such patients (see Section 4.2 Dose and Method of Administration).

Gender.

No difference in dexmedetomidine hydrochloride pharmacokinetics due to gender was observed.

Elderly.

The pharmacokinetic profile of dexmedetomidine hydrochloride was not altered by age. However, as with many drugs, the elderly may be more sensitive to the effects of dexmedetomidine. In clinical trials, there was a higher incidence of bradycardia and hypotension in elderly patients.

Children.

The pharmacokinetic profile of dexmedetomidine hydrochloride has not been studied in children.

5.3 Preclinical Safety Data

Genotoxicity.

Dexmedetomidine was not mutagenic in vitro, in either the bacterial reverse mutation assay (E coli and Salmonella typhimurium) or the mammalian cell forward mutation assay (mouse lymphoma). In a mouse micronucleus study, dexmedetomidine was not cytotoxic to bone marrow and did not increase the numbers of micronucleated PCEs at any dose tested, both in animals maintained at room temperature and in those kept warm. In addition, dexmedetomidine did not induce chromosomal aberrations in cultured human peripheral blood lymphocytes in the absence or presence of an exogenous metabolic activation system comprised of a human S9 homogenate.

Carcinogenicity.

Animal carcinogenicity studies have not been performed with dexmedetomidine.

6 Pharmaceutical Particulars

6.1 List of Excipients

Sodium chloride, water for injections.

6.2 Incompatibilities

Compatibility of dexmedetomidine with co-administration of blood, serum, or plasma has not been established. Dexmedetomidine-Teva must not be mixed with other medicinal products or diluents except those mentioned above.

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.
Use as soon as practicable after dilution to reduce microbiological hazard. If storage is necessary, hold at 2-8°C for not more than 24 hours.

6.4 Special Precautions for Storage

Store below 25°C. Store in the original container.

6.5 Nature and Contents of Container

Dexmedetomidine-Teva dexmedetomidine (as hydrochloride) concentrated injection 200 micrograms/2 mL contains 200 micrograms of dexmedetomidine (as hydrochloride) per 2 mL solution and is available in 3 mL glass vials (cartons containing 5 and 25 vials) with grey chlorobutyl rubber stoppers with Teflon coating and aluminium caps fitted with green-blue flip off polypropylene covers.

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

Dexmedetomidine hydrochloride is chemically described as (+)-4-(S)-[1-(2, 3-dimethylphenyl)ethyl]-1H -imidazole monohydrochloride and has a molecular weight of 236.7 and the empirical formula is C₁₃H₁₆N₂.HCl.

Chemical structure.

The structural formula is:

CAS number.

CAS 145108-58-3.

7 Medicine Schedule (Poisons Standard)

S4.

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