Zolpidem Tartrate 10 mg Tablets

1. Name Of The Medicinal Product

Zolpidem Tartrate 10 mg Tablets

2. Qualitative And Quantitative Composition

Each tablet contains 10mg zolpidem tartrate.

For excipients, see 6.1.

3. Pharmaceutical Form

Film-coated tablet.

White to off-white, film-coated oblong tablet, scored and engraved SN10 on one side.

4. Clinical Particulars

4.1 Therapeutic Indications

The short-term treatment of insomnia in situations where the insomnia is debilitating or is causing severe distress for the patient.

4.2 Posology And Method Of Administration

Route of administration: Oral

Zolpidem acts rapidly and therefore should be taken immediately before retiring, or in bed.

The recommended daily dose for adults is 10 mg.

As with all hypnotics, long-term use is not recommended and a course of treatment should not exceed four weeks. The duration of treatment should usually vary from a few days to two weeks with a maximum of four weeks including tapering off where clinically appropriate. In certain cases extension beyond the maximal treatment period may be necessary; if so, this should not take place without re-evaluation of the patient's status.

Special Populations

Children

Safety and effectiveness of zolpidem in paediatric patients under the age of 18 years has not been established. Therefore, zolpidem should not be prescribed in this population (see Special warnings and precautions for use: Paediatric patients).

Elderly

Elderly or debilitated patients may be especially sensitive to the effects of zolpidem therefore a 5mg dose is recommended. These recommended doses should not be exceeded.

Hepatic impairment

As clearance and metabolism of zolpidem is reduced in hepatic impairment, dosage should begin at 5mg in these patients with particular caution being exercised in elderly patients. In adults (under 65 years) dosage may be increased to 10mg only where the clinical response is inadequate and the drug is well tolerated.

4.3 Contraindications

Zolpidem tartrate is contraindicated in patients with a hypersensitivity to zolpidem tartrate or any of the inactive ingredients, obstructive sleep apnoea, myasthenia gravis, severe hepatic insufficiency, acute and/or severe respiratory depression. In the absence of data, zolpidem should not be prescribed for children or patients with psychotic illness.

4.4 Special Warnings And Precautions For Use

Respiratory Insufficiency

As hypnotics have the capacity to depress respiratory drive, precautions should be observed if zolpidem is prescribed to patients with compromised respiratory function.

Hepatic Insufficiency: See section 4.2.

The cause of insomnia should be identified wherever possible and the underlying factors treated before a hypnotic is prescribed. The failure of insomnia to remit after a 7-14 day course of treatment may indicate the presence of a primary psychiatric or physical disorder, and the patient should be carefully re-evaluated at regular intervals.

Paediatric Patients:

Safety and effectiveness of zolpidem has not been established in patients below the age of 18 years. In an 8-week study in paediatric patients (aged 6-17 years) with insomnia associated with attention-deficit/hyperactivity disorder (ADHD), in which efficacy was not demonstrated, psychiatric and nervous system disorders comprised the most frequent treatment-emergent adverse events observed with zolpidem versus placebo and included dizziness (23.5% vs. 1.5%), headache (12.5% vs. 9.2%), and hallucinations (7.4% vs. 0%).

Elderly: See dose recommendations.

Amnesia

Benzodiazepines or benzodiazepine-like agents such as zopidem may induce anterograde amnesia. The condition occurs most often several hours after ingesting the product and therefore to reduce the risk patients should ensure that they will be able to have an uninterrupted sleep of 7-8 hours.

Depression:

As with other sedative/hypnotic drugs, zolpidem should be administered with caution in patients exhibiting symptoms of depression. Suicidal tendencies may be present therefore the least amount of zolpidem that is feasible should be supplied to these patients to avoid the possibility of intentional overdosage by the patient. Pre-existing depression may be unmasked during use of zolpidem. Since insomnia may be a symptom of depression, the patient should be re-evaluated if insomnia persists.

Use in patients with a history of drug or alcohol abuse: Extreme caution should be exercised when prescribing for patients with a history of drug or alcohol abuse. These patients should be under careful surveillance when receiving zolpidem or any other hypnotic, since they are at risk of habituation and psychological dependence.

General information relating to effects seen following administration of benzodiazepines and other hypnotic agents which should be taken into account by the prescribing physician are described below

Tolerance

Some loss of efficacy to the hypnotic effects of short-acting benzodiazepines and benzodiazepine-like agents like zolpidem may develop after repeated use for a few weeks.

Dependence

Use of benzodiazepines or benzodiazepine-like agents like zolpidem may lead to the development of physical and psychological dependence. The risk of dependence increases with dose and duration of treatment; it is also greater in patients with a history of psychiatric disorders and/or alcohol or drug abuse. These patients should be under careful surveillance when receiving hypnotics.

Once physical dependence has developed, abrupt termination of treatment will be accompanied by withdrawal symptoms. These may consist of headaches or muscle pain, extreme anxiety and tension, restlessness, confusion and irritability. In severe cases the following symptoms may occur: derealisation, depersonalisation, hyperacusis, numbness and tingling of the extremities, hypersensitivity to light, noise and physical contact, hallucinations or epileptic seizures.

Rebound insomnia

A transient syndrome whereby the symptoms that led to treatment with a benzodiazepine or benzodiazepine-like agent recur in an enhanced form, may occur on withdrawal of hypnotic treatment. It may be accompanied by other reactions including mood changes, anxiety and restlessness.

It is important that the patient should be aware of the possibility of rebound phenomena, thereby minimising anxiety over such symptoms should they occur when the medicinal product is discontinued. Since the risk of withdrawal phenomena or rebound has been shown to be greater after abrupt discontinuation of treatment, it is recommended that the dosage is decreased gradually where clinically appropriate.

There are indications that, in the case of benzodiazepines and benzodiazepine-like agents with a short duration of action, withdrawal phenomena can become manifest within the dosage interval, especially when the dosage is high.

Other psychiatric and "paradoxical" reactions:

Other psychiatric and paradoxical reactions like restlessness, exacerbated insomnia, agitation, irritability, aggression, delusion, anger, nightmares, hallucinations, psychosis, abnormal behaviour and other adverse behavioural effects are known to occur when using benzodiazepines or benzodiazepine-like agents. Should this occur, use of the product should be discontinued. These reactions are more likely to occur in the elderly.

Somnambulism and associated behaviours:

Sleep walking and other associated behaviours such as “sleep driving”, preparing and eating food, making phone calls or having sex, with amnesia for the event, have been reported in patients who had taken zolpidem and were not fully awake. The use of alcohol and other CNS-depressants with zolpidem appears to increase the risk of such behaviour, as does the use of zolpidem at doses exceeding the maximum recommended dose. Discontinuation of zolpidem should be strongly considered for patients who report such behaviour (for example, sleep driving), due to the risk to the patient and others.

4.5 Interaction With Other Medicinal Products And Other Forms Of Interaction

Not recommended:

- Concomitant intake with alcohol.

The sedative effect may be enhanced when the product is used in combination with alcohol. This affects the ability to drive or use machines.

Take into account:

- Combination with CNS depressants.

Enhancement of the central depressive effect may occur in cases of concomitant use with antipsychotics (neuroleptics), hypnotics, anxiolytics/sedatives, antidepressant agents, narcotic analgesics, antiepileptic drugs, anaesthetics and sedative antihistamines. Zolpidem appears to interact with sertraline. This interaction may cause increased drowsiness. Also, isolated cases of visual hallucinations were reported.

In the case of narcotic analgesics enhancement of euphoria may also occur leading to an increase in psychological dependence.

Drugs that affect metabolism via cytochrome P450

Compounds which inhibit certain hepatic enzymes (particularly cytochrome P450) may enhance the activity of benzodiazepines and benzodiazepine-like agents.

Zolpidem is metabolised via several hepatic cytochrome P450 enzymes, the main enzyme being CYP3A4 with the contribution of CYP1A2. The pharmacodynamic effect of zolpidem is decreased when it is administered with rifampicin (a CYP3A4 inducer). However when zolpidem was administered with itraconazole (a CYP3A4 inhibitor) its pharmacokinetics and pharmacodynamics were not significantly modified. The clinical relevance of these results is unknown.

Co-administration of zolpidem with ketoconazole (200mg twice daily), a potent CYP3A4 inhibitor, prolonged zolpidem elimination half-life, increased total AUC, and decreased apparent oral clearance when compared to zolpidem plus placebo). The total AUC for zolpidem, when co-administered with ketoconazole, increased by a factor of 1.83 when compared to zolpidem alone. A routine dosage adjustment of zolpidem is not considered necessary, but patients, should be advised that use of zolpidem with ketoconazole may enhance the sedative effects.

Since CYP3A4 plays an important role in zolpidem metabolism, possible interactions with drugs that are substrates or inducers of CYP3A4 should be considered.

Other drugs:

When zolpidem was administered with ranitidine or cimetidine, no significant pharmacokinetic interactions were observed.

4.6 Pregnancy And Lactation

Although animal studies have shown no teratogenic or embryotoxic effects, safety in pregnancy has not been established. As with all drugs zolpidem should be avoided in pregnancy particularly during the first trimester.

If the product is prescribed to a woman of childbearing potential, she should be warned to contact her physician about stopping the product if she intends to become or suspects that she is pregnant.

If, for compelling medical reasons, zolpidem is administered during the late phase of pregnancy, or during labour, effects on the neonate, such as hypothermia, hypotonia and moderate respiratory depression, can be expected due to the pharmacological action of the product. Cases of severe neonatal respiratory depression have been reported when zolpidem tartrate was used with other CNS depressants at the end of pregnancy.

Infants born to mothers who took benzodiazepines or benzodiazepine-like agents chronically during the latter stages of pregnancy may have developed physical dependence and may be at some risk of developing withdrawal symptoms in the postnatal period.

Small quantities of zolpidem appear in breast milk. The use of zolpidem in nursing mothers is therefore not recommended.

4.7 Effects On Ability To Drive And Use Machines

Vehicle drivers and machine operators should be warned that, as with other hypnotics, there may be a possible risk of drowsiness the morning after therapy. In order to minimise this risk a resting period of 7 to 8 hours is recommended between taking zolpidem and driving.

4.8 Undesirable Effects

The following CIOMS frequency rating is used, when applicable:

Very common

Common

Uncommon

Rare

Very rare < 0.01%

Not known: cannot be estimated based on available data.

There is evidence of a dose-relationship for adverse effects associated with zolpidem use, particularly for certain CNS and gastrointestinal events. As recommended in section 4.2, they should in theory be less if zolpidem is taken immediately before retiring, or in bed. They occur most frequently in elderly patients.

Immune system disorders

Not known: angioneurotic oedema

Psychiatric disorders

Common: hallucination, agitation, nightmare

Uncommon: confusional state, irritability

Not known: restlessness, aggression, delusion, anger, psychoses, abnormal behaviour, somnambulism (see Section 4.4), dependence (withdrawal symptoms, or rebound effects may occur after treatment discontinuation), libido disorder

Most of these psychiatric undesirable effects are related to paradoxical reactions

Nervous system disorders:

Common: somnolence, headache, dizziness, exacerbated insomnia, anterograde amnesia: (amnestic effects may be associated with inappropriate behaviour)

Not known: depressed level of consciousness

Eye disorders

Uncommon: diplopia

Gastro-intestinal Disorders

Common: diarrheoa,

Hepatobiliary disorders

Not known: Liver enzymes elevated

Skin and subcutaneous tissue disorders

Not known: rash, pruritus, urticaria

Musculoskeletal and connective tissue disorders

Not known: muscular weakness

General disorders and administration site conditions

Common: fatigue

Not known: gait disturbance, drug tolerance, fall (predominantly in elderly patients and when zolpidem was not taken in accordance with prescribing recommendation)

4.9 Overdose

Signs and Symptoms:

In cases of overdose, involving zolpidem alone or with other CNS-depressant agents (including alcohol), impairment of consciousness ranging from somnolence to coma, and including fatal outcomes have been reported.

Management:

General symptomatic and supportive measures should be used. If there is no advantage in emptying the stomach, activated charcoal should be given to reduce absorption. Sedating drugs should be withheld even if excitation occurs.

Use of flumazenil may be considered where serious symptoms are observed. Flumazenil is reported to have an elimination half-life of about 40 to 80 minutes. Patients should be kept under close observation because of this short duration of action; further doses of flumazenil may be necessary. However, flumazenil administration may contribute to the appearance of neurological symptoms (convulsions).

The value of dialysis in the treatment of an overdose has not been determined. Dialysis in patients with renal failure receiving therapeutic doses of zolpidem has demonstrated no reduction in levels of zolpidem.

In the management of overdose with any medicinal product, it should be borne in mind that multiple agents may have been taken.

5. Pharmacological Properties

5.1 Pharmacodynamic Properties

(GABA-A receptor agonist selective for omega-1-type sub-unit hypnotic agent).

Zolpidem is an imidazopyridine which selectively binds the omega-1 receptor subtype (also known as the benzodiazepine-1 subtype) which is the alpha unit of the GABA-A receptor complex. Whereas benzodiazepines non-selectively bind all three omega receptor subtypes, zolpidem preferentially binds the omega-1 subtype. The modulation of the chloride anion channel via this receptor leads to the specific sedative effects demonstrated by zolpidem. These effects are reversed by the benzodiazepine antagonist flumazenil.

In animals: The selective binding of zolpidem to omega-1 receptors may explain the virtual absence at hypnotic doses of myorelaxant and anti-convulsant effects in animals which are normally exhibited by benzodiazepines which are not selective for omega-1 sites.

In humans: The preservation of deep sleep (stages 3 and 4 - slow-wave sleep) may be explained by the selective omega-1 binding by zolpidem. All identified effects of zolpidem are reversed by the benzodiazepine antagonist flumazenil.

5.2 Pharmacokinetic Properties

Zolpidem has both a rapid absorption and onset of hypnotic action. Bioavailability is 70% following oral administration and demonstrates linear kinetics in the therapeutic dose range. Peak plasma concentration is reached at between 0.5 and 3 hours.

The elimination half-life is short, with a mean of 2.4 hours (0.7-3.5) and a duration of action of up to 6 hours. Protein binding amounts to 92.5% ± 0.1%. First pass metabolism by the liver amounts to approximately 35%. Repeated administration has been shown not to modify protein binding indicating a lack of competition between zolpidem and its metabolites for binding sites.

The distribution volume in adults is 0.54 ± 0.02 L/kg and decreases to 0.34 ± 0.05 L/kg in the very elderly.

All metabolites are pharmacologically inactive and are eliminated in the urine (56%) and in the faeces (37%).

Zolpidem has been shown in trials to be non-dialysable.

Plasma concentrations in elderly subjects and those with hepatic impairment are increased. In patients with renal insufficiency, whether dialysed or not, there is a moderate reduction in clearance. The other pharmacokinetic parameters are unaffected.

Zolpidem is metabolised via several hepatic cytochrome P450 enzymes, the main enzyme being CYP3A4 with the contribution of CYP1A2. Since CYP3A4 plays an important role in zolpidem metabolism, possible interactions with drugs that are substrates or inducers of CYP3A4 should be considered.

5.3 Preclinical Safety Data

Preclinical data reveal no special hazard for humans based on conventional studies of safety pharmacology, repeated dose toxicity, genotoxicity, carcinogenic potential, toxicity to reproduction.

6. Pharmaceutical Particulars

6.1 List Of Excipients

Tablet core: Lactose monohydrate,

Microcrystalline cellulose,

Hypromellose,

Sodium starch glycollate,

Magnesium stearate.

Film coating: Hypromellose,

Titanium dioxide (E171),

Macrogol 400.

6.2 Incompatibilities

Not applicable

6.3 Shelf Life

4 years.

6.4 Special Precautions For Storage

No special precautions.

6.5 Nature And Contents Of Container

Cartons of 4 or 28 tablets in PVC/foil blister strips.

Not all pack sizes may be marketed.

6.6 Special Precautions For Disposal And Other Handling

Not applicable.

7. Marketing Authorisation Holder

Winthrop Pharmaceuticals UK Limited

One Onslow Street

Guildford

Surrey

GU1 4YS

United Kingdom

Trading as: Winthrop Pharmaceuticals, PO Box 611, Guildford, Surrey, GU1 4YS

8. Marketing Authorisation Number(S)

PL 17780/0018

9. Date Of First Authorisation/Renewal Of The Authorisation

15 May 2002

10. Date Of Revision Of The Text

27 October 2009