Consumer medicine information

Minirin Nasal Spray

Desmopressin acetate

BRAND INFORMATION

Brand name

Minirin Nasal Spray

Active ingredient

Desmopressin acetate

Schedule

S4

 

Consumer medicine information (CMI) leaflet

Please read this leaflet carefully before you start using Minirin Nasal Spray.

What is in this leaflet

This leaflet answers some common questions about MINIRIN Nasal Spray.

It does not contain all the available information. It does not replace of talking to your doctor or pharmacist.

All medicines have risks and benefits. Your doctor has weighed the risks of you taking MINIRIN Nasal Spray 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 MINIRIN Nasal Spray is used for

The active ingredient, desmopressin acetate, in MINIRIN Nasal Spray is a synthetic version of a naturally occurring substance produced in the brain called vasopressin.

It has a number of different actions on the body including an action on the kidney to reduce the amount of urine produced. This means that MINIRIN Nasal Spray can be used for several different conditions including:

  • primary nocturnal enuresis (bedwetting) in patients over 6 years of age, who have a normal ability to concentrate urine and who have not responded to treatment with an enuresis alarm or in patients in whom an enuresis alarm is contraindicated or inappropriate and where the oral administration of desmopressin is not feasible..
  • cranial diabetes insipidus (large amounts of urine being produced day and night and constant thirst)
  • as a diagnostic test to establish if the kidneys have the ability to concentrate urine.

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.

It is available only with a doctor's prescription.

This medicine is not expected to affect your ability to drive a car or operate machinery.

Before you use MINIRIN Nasal Spray

When you must not use it

Do not use MINIRIN Nasal Spray if you have an allergy to:

  • any medicine containing desmopressin or 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 use MINIRIN Nasal Spray if you:

  • suffer from polydipsia (excessive thirst and increased fluid intake) or psychogenic polydipsia (psychologically caused increased thirst and increased fluid intake) or where you are in the habit of drinking large amounts of fluid
  • have cardiac insufficiency (heart failure in which the heart is not able to pump enough blood throughout the body resulting in shortness of breath, swelling of the feet or legs due to fluid build-up)
  • you are taking diuretics (water or fluid tablets)
  • have moderately or severely reduced kidney function where you pass little or no urine
  • have low levels of sodium in your blood
  • have SIADH (hormone secretion disorder where there is an overproduction of a hormone causing fluid retention, resulting in weakness, tiredness or confusion).

Do not breast-feed if you are using this medicine. MINIRIN Nasal Spray is not recommended while you are breast-feeding.

Do not give this medicine to a child under the age of 6 years. Safety and effectiveness in children younger than 6 years have not been established.

Do not use 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.

MINIRIN Nasal Spray should only be used when oral forms of MINIRIN are inappropriate. This is because a side-effect that can change the fluid and salt balance in your body is less common with oral forms. For further information, please discuss this with your doctor.

If you are not sure whether you should start using this medicine, talk to your doctor.

Before you start to use it

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

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

  • a known allergy to anti-diuretic hormone (ADH)
  • too little or too much fluid in the body
  • currently have a nasal infection or blocked up or runny nose
  • heart or blood vessel disease or any other disease for which you take diuretics
  • low blood pressure
  • cystic fibrosis any medical condition causing fluid and/or electrolyte imbalance
  • any medical condition that could be made worse by fluid and/or electrolyte disturbance
  • any disease of the blood clotting cells (platelets)
  • serious problems with bladder function or with passing urine.

Tell your doctor if you are pregnant or plan to become pregnant or are breast-feeding.

MINIRIN Nasal Spray should only be used in a pregnant woman if necessary. Your doctor can discuss with you the risks and benefits involved.

Do not breast-feed if you are using this medicine. The active ingredient in MINIRIN Nasal Nasal Spray passes into breast milk. Therefore this medicine is not recommended while you are breast-feeding.

If you have not told your doctor about any of the above, tell him/her before you start using MINIRIN Nasal Spray.

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 MINIRIN Nasal Spray may interfere with each other. These include:

  • tricyclic antidepressants, which are medicines used to treat e.g. depression (such as clomipramine, imipramine, desipramine)
  • selective serotonin reuptake inhibitors (SSRIs), which are medicines used to treat e.g. depression or anxiety (such as citalopram, paroxetine, sertraline)
  • chlorpromazine, which is an anti-psychotic medicinal product used to treat e.g. schizophrenia
  • carbamazepine, which is used to treat e.g. bipolar disorder and epilepsy
  • antidiabetic medicinal products used for type II diabetes (medicines in the sulfonylurea group), particularly chlorpropamide
  • medicines used to treat high blood pressure and some other conditions (ACE inhibitors or angiotensin receptor blockers e.g. enalapril, perindopril, irbesartan etc.)
  • non-steroidal anti-inflammatory drugs (NSAIDs), which are medicinal products used for the treatment of pain and inflammation (e.g. aspirin and ibuprofen).

These medicines may be affected by MINIRIN Nasal Spray 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 use MINIRIN Nasal Spray

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

The instructions on how to use MINIRIN Nasal Spray are included in the carton.

It is very important for you to follow these instructions closely to make sure that you will always receive the correct dose of your medication. MINIRIN Nasal Spray is meant to be sprayed into the nostrils. Do not inhale (sniff the spray).

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

How much to use

Some of the details for MINIRIN Nasal Spray will vary depending on the purpose for which it is used.

Bedwetting (nocturnal enuresis)
The usual starting dose is one spray (10 micrograms) into each nostril at bedtime. The dose will then be adjusted by your doctor according to your response. The maximum dose is two sprays in each nostril (40 micrograms).

Fluid intake should be limited in preparation for your dose of MINIRIN Nasal Spray (see 'Things to be careful of').

Cranial diabetes insipidus
The dose you need will be adjusted to suit your personal requirements. The daily dose is usually given as two divided doses. Sometimes a single daily dose is sufficient to control your condition. For children the daily doses vary up to two sprays (20 micrograms). For adults the daily doses vary up to four sprays (40 micrograms).

Since MINIRIN Nasal Spray cannot deliver doses less than 10 micrograms per spray, the MINIRIN Intranasal Solution and the rhinyle delivery system will need to be used, if lower doses are needed.

When to use it

Bedwetting (nocturnal enuresis)

  • use MINIRIN Nasal Spray at bedtime.

Cranial diabetes insipidus

  • use MINIRIN Nasal Spray at times specified by your doctor.

How long to use 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.

Bedwetting (nocturnal enuresis)
MINIRIN Nasal Spray for bedwetting is usually taken for periods up to three months.

After this period you should have at least one week without MINIRIN Nasal Spray to check if your bedwetting has stopped. If not, continue for another three months.

Cranial diabetes insipidus
Your doctor will advise you.

Test the ability of the kidneys to concentrate urine
Your doctor will advise you.

If a dose is missed

Bedwetting (nocturnal enuresis)
Skip the missed dose and take the next dose when you are meant to.

Cranial diabetes insipidus
Take the next dose as soon as you remember. You will then have to adjust the time of the following dose.

When this is done, go back to taking your medicine as you would normally. You should talk to your doctor about this situation. Do not take a double dose.

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

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

Test the ability of the kidneys to concentrate urine
If you are an adult, you will require a single dose of up to 40 micrograms at any one time.

If you are a child, you will require a single dose of up to 10 micrograms at any one time.

Children who are less than one year of age and need to be tested for the ability of the kidney to concentrate urine should require this test under careful supervision in hospital.

If you take too much (overdose)

Immediately telephone your doctor or the Poisons Information Centre (telephone 13 11 26) for advice, or go to Accident and Emergency at the nearest hospital, if you think that you or anyone else may have taken too much MINIRIN Nasal Spray. Do this even if there are no signs of discomfort or poisoning. You may need urgent medical attention.

Symptoms of an overdose may include confusion, drowsiness, continuing headache, nausea or vomiting, rapid weight gain due to a build-up of water in the body, or, in severe cases, convulsions.

While you are using MINIRIN Nasal Spray

Things you must do

If you are about to be started on any new medicine, remind your doctor and pharmacist that you are using MINIRIN Nasal Spray.

Tell any other doctors, dentists, and pharmacists who treat you that you are using this medicine.

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

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

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

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 use MINIRIN Nasal Spray to treat any other complaints unless your doctor tells you to do so.

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

Do not stop using your medicine or change the dosage without checking with your doctor. If you stop taking it suddenly, your condition may worsen.

Things to be careful of

All patients on treatment with this medicine should avoid excessive fluid intake as this may lead to a build-up of water in the body.

Bedwetting (nocturnal enuresis)

You must avoid drinking fluids from one hour before using MINIRIN Nasal Spray until at least eight hours after administration of the Nasal Spray. Over this period, drink no more than a few sips of water or other fluids. This is because a high fluid intake during this period can increase the chance that you will feel unwell (e.g. headache, nausea, dizziness).

Remember to drink normally throughout the day. This is very important to prevent dehydration.

Cranial diabetes insipidus

Carefully follow your doctor's instruction about fluid intake.

It is very important to keep your body water in balance, so that you do not let yourself get too thirsty or drink too much fluid.

Test the ability of the kidneys to concentrate urine

You must avoid drinking fluids from one hour before using MINIRIN Nasal Spray until at least eight hours after administration of the Nasal Spray. Over this period, drink no more than a few sips of water or other fluids. This is because a high fluid intake during this period can increase the chance that you will feel unwell (e.g. headache, nausea, dizziness).

Side effects

Tell your doctor or pharmacist as soon as possible if you do not feel well while you are using MINIRIN Nasal Spray.

This medicine helps 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 60 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:

  • nasal congestion
  • runny or blocked nose, sneezing, facial pressure or pain
  • increased body temperature (fever)
  • trouble sleeping
  • nightmare
  • nervousness
  • headache
  • nose bleed
  • upper respiratory tract infection
  • inflammation of the stomach and intestines
  • stomach pain or nausea.

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 you notice any of the following:

  • emotional, behavioural or visual disturbances
  • allergic reactions including skin rash or more general reactions.

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

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

  • confusion or drowsiness
  • continuing headache
  • nausea or vomiting
  • rapid weight gain, which may be due to a build-up of water in the body
  • convulsions, fitting and blackouts.

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

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 MINIRIN Nasal Spray

Storage

Keep MINIRIN Nasal Spray in the original container in upright position in order to protect from moisture and light until it is time to take it. If you store the medicine out of its original packaging it may not keep well.

Keep MINIRIN Nasal Spray in a cool dry place where the temperature stays below 25°C.

Do not store MINIRIN Nasal Spray, or any other medicine, in the bathroom or near a sink. Do not leave it on a window sill or in the car. 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 using this medicine or the expiry date has passed, ask your pharmacist what to do with any medicine that is left over.

Product description

What it looks like

MINIRIN Nasal Spray of 6 mL is supplied in a brown, glass bottle equipped with a pre-compression spray pump delivering 60 doses of 10 micrograms desmopressin acetate.

Ingredients

MINIRIN Nasal Spray contains 10 micrograms of desmopressin acetate, as the active ingredient per one actuation/spray.

It also contains:

  • sodium chloride
  • citric acid monohydrate
  • dibasic sodium phosphate dihydrate
  • benzalkonium chloride
  • purified water.

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

Sponsor

MINIRIN Nasal Spray is supplied in Australia by:

Ferring Pharmaceuticals Pty Ltd
Suite 2, Level 1, Building 1
20 Bridge Street
Pymble, NSW 2073
Australia.

AUST R 59320 - MINIRIN desmopressin acetate 10 microgram/actuation nasal spray

This leaflet was prepared in August 2019.

DOCS#878-v9A

MINIRIN and FERRING are registered trademarks of Ferring B.V.

Published by MIMS November 2019

BRAND INFORMATION

Brand name

Minirin Nasal Spray

Active ingredient

Desmopressin acetate

Schedule

S4

 

1 Name of Medicine

Desmopressin acetate.

2 Qualitative and Quantitative Composition

Minirin Nasal Spray also contains sodium chloride, citric acid monohydrate, dibasic sodium phosphate-dihydrate, benzalkonium chloride solution 50% as preservative and water-purified.
Desmopressin free base represents 89% of the desmopressin acetate content. This is due to the difference in molecular weight as well as the presence of acetic acid/ acetate, water and impurities.

3 Pharmaceutical Form

Nasal spray, solution.

4 Clinical Particulars

4.1 Therapeutic Indications

Diabetes insipidus.

The treatment of ADH sensitive cranial diabetes insipidus, including treatment of posthypophysectomy polydipsia and polyuria.

Nocturnal enuresis.

Minirin Nasal Spray is indicated for the symptomatic treatment of primary nocturnal enuresis in patients who have normal ability to concentrate urine. Minirin Nasal Spray should be used only in patients who are refractory to the enuresis alarm or in patients in whom enuresis alarm is contraindicated or inappropriate, and where the oral administration of desmopressin is not feasible.

Renal concentrating capacity.

By intranasal administration to adults and children as a diagnostic test to establish renal concentrating capacity.

4.2 Dose and Method of Administration

Note.

Minirin Nasal Spray is for intranasal administration only. Administration of desmopressin acetate by intravenous or intramuscular injection may be used when the intranasal route is inconvenient.

Caution.

The intravenous or intramuscular dose is about one tenth of the intranasal dose.

For ADH-sensitive cranial diabetes insipidus.

Adult. The average daily dose is 10 to 40 microgram intranasally.
Paediatric.

Intranasal.

2.5 to 20 micrograms daily.
The daily dose is usually given as two divided doses. The dosage must be determined for each individual patient and adjusted according to the diurnal pattern of response. Response should be estimated by two parameters: adequate duration of sleep and adequate, but not excessive, water turnover. In the event of signs of water retention/ hyponatraemia, treatment should be interrupted and the dose adjusted. A single daily dose may be appropriate if it is tolerated and also satisfactorily controls the diabetes insipidus. About one third of patients may be controlled on a small daily dose. For immediate postoperative polyuria and polydipsia, the dose should be controlled by measurement of the urine osmolality. Monitoring in a high dependency setting is recommended. If there is doubt that a dose has been administered, a second dose should not be given until diuresis has occurred.

Primary nocturnal enuresis.

Dosage should be adjusted according to the individual. The recommended initial dose for those 6 years of age and older is 20 microgram or 0.2 mL solution intranasally at bedtime. Adjustment up to 40 microgram is suggested if the patient does not respond. Some patients may respond to 10 and a downward adjustment to 10 microgram can be made if the patient responds to 20 microgram. Note that each actuation of the spray contains 10 microgram of desmopressin acetate. It is recommended that one-half of the dose be administered per nostril. Since the spray cannot deliver less than 10 microgram, smaller doses should be delivered by the rhinyle delivery system. A restricted fluid intake is recommended overnight after administration (see Section 4.4 Special Warnings and Precautions for Use, fluid intake). Patients should be treated for an initial period of 1-3 months followed by a withdrawal of 1 week to assess cure rate. Relapsed patients should be continued for a further 1-3 months at the standard dose.

As a diagnostic test of renal concentrating capacity.

See Section 4.4 Special Warnings and Precautions for Use.
Intranasal.

Adults.

Single dose of up to 40 micrograms.

Children.

Single dose of up to 20 micrograms.

Infants

Single dose of up to 10 microgram (see Section 4.4 Special Warnings and Precautions for Use).

Instructions to be given to patients.

The physician should carefully explain the use of the spray device and advise the patient not to inhale. Patients should be instructed to read accompanying directions on use of the spray pump carefully before use. Prime the spray before using it for the first time by pressing it at least four times, or until an even spray is obtained. If the spray has not been used during the last 7 days it is necessary to prime it again by pressing it a couple of times until an even spray is obtained before placing the nozzle in the nostril.

4.3 Contraindications

Habitual and psychogenic polydipsia (resulting in a urine production exceeding 40 mL/kg/24 hours).
A history of known or suspected cardiac insufficiency and other conditions requiring treatment with diuretics.
Moderate and severe renal insufficiency (creatinine clearance below 50 mL/min).
Known hyponatraemia.
Syndrome of inappropriate antidiuretic hormone secretion (SIADH).
Hypersensitivity to desmopressin acetate or any of the excipients in Minirin Nasal Spray.

4.4 Special Warnings and Precautions for Use

Desmopressin acetate is ineffective for the treatment of nephrogenic diabetes insipidus.
Only use Minirin Nasal Spray in patients where orally administered formulations are not feasible (see Section 4.8 Adverse Effects (Undesirable Effects), Postmarketing experience).

Hyponatraemia and hydration.

Hyponatraemia in the context of the use of desmopressin is generally due to fluid overload, thus careful attention to fluid balance is needed. Other causes of hyponatraemia which may need excluding depending on the clinical situation include renal salt wasting due to central lesions, renal disorders or adrenal disorders. There is some evidence from postmarketing data for the occurrence of severe hyponatraemia in association with the nasal spray formulation of desmopressin when it is used in the treatment of central diabetes insipidus.

Central diabetes insipidus.

The aim of fluid therapy is to replace urinary fluid loss.
Children, patients with cognitive impairment, and patients with inadequate thirst sensation need close monitoring of fluid intake.
Regular monitoring of serum and urinary sodium and osmolality is recommended at the discretion of the clinician.

Primary nocturnal enuresis.

When used for the treatment of primary nocturnal enuresis the fluid intake must be limited to a minimum from 1 hour before until 8 hours after administration.
Check serum electrolytes at least once if therapy is continued beyond 7 days.

Testing of renal concentrating capacity.

When used for diagnostic purposes the fluid intake must be limited to a maximum of 0.5 L to satisfy thirst from 1 hour before until at least 8 hours after administration. Renal concentrating capacity testing in children below the age of 1 year should only be performed under carefully supervised conditions in hospital.
When Minirin Nasal Spray is prescribed it is recommended to start at the lowest dose, ensure compliance with fluid restriction instructions; increase dose progressively, with caution; ensure adult supervision when a child is administering the drug in order to control the dose intake.
Desmopressin acetate should not be administered to dehydrated or overhydrated patients until water balance has been adequately restored.

Nasal infections/ rhinorrhoea.

Intranasal administration may be ineffective and unreliable absorption may result in the presence of local infection or rhinorrhoea. In patients being treated for enuresis, treatment should cease until the nasal condition resolves. Bodyweight should be regularly monitored.

Myocardial ischaemia.

Desmopressin acetate should be used with caution in patients with cardiovascular disease and the elderly.

Hypersensitivity.

Patients with a known hypersensitivity to ADH should be tested for sensitivity to desmopressin acetate before the full dose is given.

Postoperative use.

The use of desmopressin in a postoperative setting should only occur after the diagnosis of diabetes insipidus has been confirmed. Small doses should be administered with strict fluid balance and regular clinical assessment.
Minirin Nasal Spray should be used with caution in patients with cystic fibrosis because of impaired water handling and increased risk of hyponatraemia.
Precautions to prevent fluid overload must be taken in patients at risk of increased intracranial pressure.
Severe bladder dysfunction and outlet obstruction should be considered before starting treatment for primary nocturnal enuresis.
Treatment with desmopressin should be interrupted or carefully adjusted during acute intercurrent illnesses characterised by fluid and/or electrolyte imbalance (such as systemic infections, fever, gastroenteritis.

Additional information.

High doses of desmopressin, such as those used to treat bleeding, are contraindicated in patients with type IIB von Willebrand's disease. Use of Minirin Nasal Spray in this patient group is not approved or recommended. At high doses, intravenously administered desmopressin has a vasodilatory effect and may cause a minor decrease in systolic or diastolic blood pressure. In haemophilia where high doses are given extreme care is paid to water balance.
Due to the presence of benzalkonium chloride, Minirin Nasal Spray may cause bronchospasm.

Use in elderly.

See Section 4.4 Special Warnings and Precautions for Use.

Paediatric use.

See Section 4.4 Special Warnings and Precautions for Use.

Effects on laboratory tests.

See Section 4.4 Special Warnings and Precautions for Use.

4.5 Interactions with Other Medicines and Other Forms of Interactions

See Table 1.
Use of large doses of intranasal desmopressin with other pressor agents should only be done with careful patient monitoring.
It is unlikely that desmopressin will interact with drugs affecting hepatic metabolism, since desmopressin has been shown not to undergo significant liver metabolism in in vitro studies with human microsomes. However, formal in vivo interaction studies have not been performed.

4.6 Fertility, Pregnancy and Lactation

Effects on fertility.

No data available.
(Category B1)
Caution should be exercised when prescribing to pregnant women.
Data on a limited number (n = 53) of exposed pregnancies in women with diabetes insipidus as well as data on a limited number of exposed pregnancies in women with bleeding complications (n = 216) indicate no adverse effects of desmopressin on pregnancy or on the health of the fetus/ newborn child. To date, no other relevant epidemiological data are available. Animal studies do not indicate direct or indirect harmful effects with respect to pregnancy, embryonic/ fetal development, parturition or postnatal development.
Embryofetal development studies performed with desmopressin in rats and rabbits given subcutaneous doses up to 50 nanogram/kg/day and 200 microgram/kg/day, respectively, and in rats given intravenous doses up to 241 microgram/kg/day, revealed no evidence for a harmful effect on the fetus.
Subtherapeutic levels of desmopressin acetate have been detected in the breast milk of lactating women. Until further evidence of its safe use during lactation is available, it is not to be administered to lactating women.

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)

Clinical trials.

Primary nocturnal enuresis.

Table 2 lists the percentage of patients having adverse experiences without regard to relationship to study drug from the pooled pivotal study data for primary nocturnal enuresis.
Table 3 is based on the frequency of adverse drug reactions reported in clinical trials with Minirin Nasal Spray, conducted in children and adults for treatment of central diabetes insipidus (CDI), primary nocturnal enuresis (PNE) and renal concentrating capacity testing (RCCT) (n = 745).

Postmarketing experience.

Table 4 are additional adverse drug reactions reported in the postmarketing period in children, adolescents and adults treated with desmopressin nasal spray, distributed by organ class. The frequency of adverse drug reactions occurring in the postmarketing period is unknown.

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 http://www.tga.gov.au/reporting-problems.

4.9 Overdose

Overdose of Minirin Nasal Spray leads to a prolonged duration of action with an increased risk of water retention and hyponatraemia.

Treatment.

Treatment of hyponatraemia should be individualised. Treatment should include discontinuing desmopressin treatment, instigation fluid restriction and symptomatic treatment, if needed.
For information on the management of overdose, contact the Poisons Information Centre on 131126 (Australia).

5 Pharmacological Properties

5.1 Pharmacodynamic Properties

Pharmacotherapeutic group: vasopressin and analogues.
ATC code: H01B A02.
Minirin Nasal Spray contains desmopressin, a structural analogue of the natural pituitary hormone arginine vasopressin, also known as antidiuretic hormone (ADH). Early treatment of central diabetes insipidus used a more or less purified extract from bovine or porcine posterior pituitaries. These caused unpleasant complications of use. When vasopressin became known, two forms were found: arginine vasopressin (found in humans) and lysine vasopressin (found in pig pituitaries).
Two chemical changes have been made to the natural hormone to form desmopressin: a) desamination of the N-terminal of cysteine-1; b) substitution of 8-D-arginine for 8-L-arginine.
According to results from antidiuretic and pressor tests in rats these changes increase antidiuretic activity three to fivefold, while pressor activity is reduced to 0.1% of that of ADH.

Mechanism of action.

The actions of Minirin can be summarised as follows.

Antidiuretic action.

Minirin acts at a receptor site in the renal collecting tubule to increase permeability to water reabsorption.

Effect on factor VIII.

High doses (0.3 micrograms/kg intravenously) of desmopressin acetate produce marked and sustained increases of factor VIII coagulant activity (VIII:C) as well as of the von Willebrand factor (vWF). At the same time plasminogen activator is released.

Effect on bleeding time.

At doses of 0.3 to 0.4 microgram/kg intravenously, desmopressin acetate results in a normalisation of, or marked reduction in, the prolonged skin (template) bleeding time. The exact mechanism of this effect is not known.
It is not known whether the effects of Minirin are direct or act through a mediator or second messenger.
There is a temporal correlation between a reduction in bleeding time and the presence in plasma of high molecular weight monomers of the von Willebrand factor which are thought to be released from storage sites.
It is thought likely that Minirin exerts its effect through its V2-receptor agonist activity.
Desmopressin acetate is thought to be resistant to the inactivation that occurs with ADH. Intravenous or intramuscular doses should be about one tenth the intranasal dose for equivalent efficacy.
In some patients, the duration of effect may be sufficiently long to permit once daily dosage if the single dose can be tolerated.

Other effects.

Oxytocic effect.

A slight in vitro oxytocic effect has been reported in animals. A slight stimulatory effect on uterine activity in nonpregnant women has been noted at doses of 15 and 20 micrograms intranasally (see Section 4.6 Fertility, Pregnancy and Lactation, Use in pregnancy).

Clinical trials.

Relevant data not documented in this Product Information.

5.2 Pharmacokinetic Properties

Absorption.

Using i.v. or i.m. doses, 100% of desmopressin is systematically available. Used intranasally, it is estimated that 10% is available. Thus, i.v. or i.m. doses are one tenth that of the intranasal route. The extent of absorption is similar for the spray and the rhinyle, with a trend towards higher absorption associated with the spray. Mean Cmax and AUC values are approximately 40% higher with the spray than with the rhinyle; however, there is considerable intra and inter individual variability in plasma levels of desmopressin.

Distribution.

It is believed to be similar to ADH. No information is available on protein binding.

Metabolism.

It is thought that the presence of the D-isomer in position eight protects desmopressin acetate from the enzyme which inactivates ADH.

Excretion.

The excretion of desmopressin acetate is similar to that of ADH but considerably slower. Clinically intranasal desmopressin acetate is effective for approximately 10-12 hours.

Half-life.

No information is available for intranasal administration. For i.v. administration of labelled desmopressin acetate, biexponential half-lives of 7.8 minutes and 75.5 minutes were recorded. The duration of drug effect is 8-20 hours, with much individual variation.

5.3 Preclinical Safety Data

Genotoxicity.

No data available.

Carcinogenicity.

No data available.

6 Pharmaceutical Particulars

6.1 List of Excipients

See Section 2 Qualitative and Quantitative Composition.

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 25°C. Protect from light. Do not freeze.

6.5 Nature and Contents of Container

Spray pump of 5 mL delivering 50 doses of 10 micrograms desmopressin acetate.
Spray pump of 6 mL delivering 60 doses of 10 micrograms desmopressin acetate. Not all pack sizes are being distributed in Australia.

6.6 Special Precautions for Disposal

In Australia, any unused medicine or waste material should be disposed of in accordance with local requirements.

6.7 Physicochemical Properties

Synonyms of desmopressin.

DDAVP; 1-desamino-8-D-arginine vasopressin; desamino-cys-1-D-arginine-8-vasopressin.

Chemical structure.


CAS number.

CAS No (base): 16679-58-6.
Molecular weight (base): 1069.22.
Desmopressin is a white, fluffy powder, soluble in water, alcohol and glacial acetic acid.

7 Medicine Schedule (Poisons Standard)

S4.

Summary Table of Changes