Ambien CR (zolpidem tartrate extended-release tablets) is indicated for the treatment of insomnia characterized by difficulties with sleep onset and/or sleep maintenance (as measured by wake time after sleep onset).
The clinical trials performed in support of efficacy were up to 3 weeks (using polysomnography measurement up to 2 weeks in both adult and elderly patients) and 24 weeks (using patient-reported assessment in adult patients only) in duration [see Clinical Studies (14)].
Ambien CR Dosage and Administration
The dose of Ambien CR should be individualized.
Dosage in adults
The recommended dose of Ambien CR for adults is 12.5 mg once daily immediately before bedtime. The total Ambien CR dose should not exceed 12.5 mg per day.
Special populations
Elderly or debilitated patients may be especially sensitive to the effects of zolpidem tartrate. Patients with hepatic insufficiency do not clear the drug as rapidly as normals. The recommended dose of Ambien CR in both of these patient populations is 6.25 mg once daily immediately before bedtime [see Warnings and Precautions (5.6)].
Use with CNS depressants
Dosage adjustments may be necessary when Ambien CR is combined with other CNS depressant drugs because of the potentially additive effects [see Warnings and Precautions (5.5)].
Administration
Ambien CR extended-release tablets should be swallowed whole, and not be divided, crushed, or chewed. The effect of Ambien CR may be slowed by ingestion with or immediately after a meal.
Dosage Forms and Strengths
Ambien CR is available as extended-release tablets containing 6.25 mg or 12.5 mg of zolpidem tartrate for oral administration. Tablets are not scored.
Ambien CR 6.25 mg tablets are pink, round, bi-convex, and debossed with A~ on one side.
Ambien CR 12.5 mg tablets are blue, round, bi-convex, and debossed with A~ on one side.
Contraindications
Ambien CR is contraindicated in patients with known hypersensitivity to zolpidem tartrate or to any of the inactive ingredients in the formulation. Observed reactions include anaphylaxis and angioedema [see Warnings and Precautions (5.2)].
Warnings and Precautions
Need to evaluate for co-morbid diagnoses
Because sleep disturbances may be the presenting manifestation of a physical and/or psychiatric disorder, symptomatic treatment of insomnia should be initiated only after a careful evaluation of the patient. The failure of insomnia to remit after 7 to 10 days of treatment may indicate the presence of a primary psychiatric and/or medical illness that should be evaluated. Worsening of insomnia or the emergence of new thinking or behavior abnormalities may be the consequence of an unrecognized psychiatric or physical disorder. Such findings have emerged during the course of treatment with sedative/hypnotic drugs, including zolpidem.
Severe anaphylactic and anaphylactoid reactions
Rare cases of angioedema involving the tongue, glottis or larynx have been reported in patients after taking the first or subsequent doses of sedative-hypnotics, including zolpidem. Some patients have had additional symptoms such as dyspnea, throat closing or nausea and vomiting that suggest anaphylaxis. Some patients have required medical therapy in the emergency department. If angioedema involves the throat, glottis or larynx, airway obstruction may occur and be fatal. Patients who develop angioedema after treatment with zolpidem should not be rechallenged with the drug.
Abnormal thinking and behavioral changes
A variety of abnormal thinking and behavior changes have been reported to occur in association with the use of sedative/hypnotics. Some of these changes may be characterized by decreased inhibition (e.g. aggressiveness and extroversion that seemed out of character), similar to effects produced by alcohol and other CNS depressants. Visual and auditory hallucinations have been reported as well as behavioral changes such as bizarre behavior, agitation and depersonalization. In controlled trials, <1% of adults with insomnia who received zolpidem reported hallucinations. In a clinical trial, 7.4% of pediatric patients with insomnia associated with attention-deficit/hyperactivity disorder (ADHD), who received zolpidem reported hallucinations [see Use in Specific Populations (8.4)].
Complex behaviors such as "sleep-driving" (i.e., driving while not fully awake after ingestion of a sedative-hypnotic, with amnesia for the event) have been reported with sedative-hypnotics, including zolpidem. These events can occur in sedative-hypnotic-naive as well as in sedative-hypnotic-experienced persons. Although behaviors such as "sleep-driving" may occur with Ambien CR alone at therapeutic doses, the use of alcohol and other CNS depressants with Ambien CR appears to increase the risk of such behaviors, as does the use of Ambien CR at doses exceeding the maximum recommended dose. Due to the risk to the patient and the community, discontinuation of Ambien CR should be strongly considered for patients who report a "sleep-driving" episode. Other complex behaviors (e.g., preparing and eating food, making phone calls, or having sex) have been reported in patients who are not fully awake after taking a sedative-hypnotic. As with "sleep-driving", patients usually do not remember these events. Amnesia, anxiety and other neuro-psychiatric symptoms may occur unpredictably.
In primarily depressed patients, worsening of depression, including suicidal thoughts and actions (including completed suicides), have been reported in association with the use of sedative/hypnotics.
It can rarely be determined with certainty whether a particular instance of the abnormal behaviors listed above is drug induced, spontaneous in origin, or a result of an underlying psychiatric or physical disorder. Nonetheless, the emergence of any new behavioral sign or symptom of concern requires careful and immediate evaluation.
Withdrawal effects
Following the rapid dose decrease or abrupt discontinuation of sedative/hypnotics, there have been reports of signs and symptoms similar to those associated with withdrawal from other CNS-depressant drugs [see Drug Abuse and Dependence (9)].
CNS depressant effects
Ambien CR, like other sedative/hypnotic drugs, has CNS-depressant effects. Due to the rapid onset of action, Ambien CR should only be taken immediately prior to going to bed. Patients should be cautioned against engaging in hazardous occupations requiring complete mental alertness or motor coordination such as operating machinery or driving a motor vehicle after ingesting the drug, including potential impairment of the performance of such activities that may occur the day following ingestion of Ambien CR. Ambien CR showed additive effects when combined with alcohol and should not be taken with alcohol. Patients should also be cautioned about possible combined effects with other CNS-depressant drugs. Dosage adjustments may be necessary when Ambien CR is administered with such agents because of the potentially additive effects.
Special populations
Use in the elderly and/or debilitated patients: Impaired motor and/or cognitive performance after repeated exposure or unusual sensitivity to sedative/hypnotic drugs is a concern in the treatment of elderly and/or debilitated patients. Therefore, the recommended Ambien CR dosage is 6.25 mg in such patients to decrease the possibility of side effects [see Dosage and Administration (2.2)]. These patients should be closely monitored.
Use in patients with concomitant illness: Clinical experience with Ambien CR (zolpidem tartrate) in patients with concomitant systemic illness is limited. Caution is advisable in using Ambien CR in patients with diseases or conditions that could affect metabolism or hemodynamic responses.
Although studies did not reveal respiratory depressant effects at hypnotic doses of zolpidem in normals or in patients with mild to moderate chronic obstructive pulmonary disease (COPD), a reduction in the Total Arousal Index together with a reduction in lowest oxygen saturation and increase in the times of oxygen desaturation below 80% and 90% was observed in patients with mild-to-moderate sleep apnea when treated with an immediate-release formulation of zolpidem tartrate (10 mg) when compared to placebo. Since sedative/hypnotics have the capacity to depress respiratory drive, precautions should be taken if Ambien CR is prescribed to patients with compromised respiratory function. Post-marketing reports of respiratory insufficiency, most of which involved patients with pre-existing respiratory impairment, have been received. Ambien CR should be used with caution in patients with sleep apnea syndrome or myasthenia gravis.
Data in end-stage renal failure patients repeatedly treated with an immediate-release formulation of zolpidem tartrate (10 mg) did not demonstrate drug accumulation or alterations in pharmacokinetic parameters. No dosage adjustment in renally impaired patients is required; however, these patients should be closely monitored [see Clinical Pharmacology (12.3)].
A study in subjects with hepatic impairment did reveal prolonged elimination in this group; therefore, treatment should be initiated with Ambien CR 6.25 mg in patients with hepatic compromise, and they should be closely monitored [see Dosage and Administration (2.2) and Clinical Pharmacology (12.3)].
Use in patients with depression: As with other sedative/hypnotic drugs, Ambien CR should be administered with caution to patients exhibiting signs or symptoms of depression. Suicidal tendencies may be present in such patients and protective measures may be required. Intentional overdosage is more common in this group of patients; therefore, the least amount of drug that is feasible should be prescribed for the patient at any one time.
Use in pediatric patients: Safety and effectiveness of zolpidem has not been established in pediatric patients. In an 8-week study in pediatric patients (aged 6–17 years) with insomnia associated with ADHD given an immediate-release oral solution of zolpidem tartrate, zolpidem did not decrease sleep latency compared to placebo. Hallucinations were reported in 7.4% of the pediatric patients who received zolpidem; none of the pediatric patients who received placebo reported hallucinations [see Use in Specific Populations (8.4)].
Adverse Reactions
The following serious adverse reactions are discussed in greater detail in other sections of the labeling:
- Serious anaphylactic and anaphylactoid reactions [see Warnings and Precautions (5.2)]
- Abnormal thinking, behavior changes, and complex behaviors [see Warnings and Precautions (5.3)]
- Withdrawal effects [see Warnings and Precautions (5.4)]
- CNS-depressant effects [see Warnings and Precautions (5.5)]
Clinical trials experience
Associated with discontinuation of treatment: In 3-week clinical trials in adults and elderly patients (> 65 years), 3.5% (7/201) patients receiving Ambien CR 6.25 or 12.5 mg discontinued treatment due to an adverse reaction as compared to 0.9% (2/216) of patients on placebo. The reaction most commonly associated with discontinuation in patients treated with Ambien CR was somnolence (1%).
In a 6-month study in adult patients (18–64 years of age), 8.5% (57/669) of patients receiving Ambien CR 12.5 mg as compared to 4.6% on placebo (16/349) discontinued treatment due to an adverse reaction. Reactions most commonly associated with discontinuation of Ambien CR included anxiety (anxiety, restlessness or agitation) reported in 1.5% (10/669) of patients as compared to 0.3% (1/349) of patients on placebo, and depression (depression, major depression or depressed mood) reported in 1.5% (10/669) of patients as compared to 0.3% (1/349) of patients on placebo.
Data from a clinical study in which selective serotonin reuptake inhibitor- (SSRI-) treated patients were given zolpidem revealed that four of the seven discontinuations during double-blind treatment with zolpidem (n=95) were associated with impaired concentration, continuing or aggravated depression, and manic reaction; one patient treated with placebo (n =97) was discontinued after an attempted suicide.
Most commonly observed adverse reactions in controlled trials: During treatment with Ambien CR in adults and elderly at daily doses of 12.5 mg and 6.25 mg, respectively, each for three weeks, the most commonly observed adverse reactions associated with the use of Ambien CR were headache, next-day somnolence, and dizziness.
In the 6-month trial evaluating Ambien CR 12.5 mg, the adverse reaction profile was consistent with that reported in short-term trials, except for a higher incidence of anxiety (6.3% for Ambien CR versus 2.6% for placebo).
Adverse reactions observed at an incidence of ≥1% in controlled trials: The following tables enumerate treatment-emergent adverse reaction frequencies that were observed at an incidence equal to 1% or greater among patients with insomnia who received Ambien CR in placebo-controlled trials. Events reported by investigators were classified utilizing the MedDRA dictionary for the purpose of establishing event frequencies. The prescriber should be aware that these figures cannot be used to predict the incidence of side effects in the course of usual medical practice, in which patient characteristics and other factors differ from those that prevailed in these clinical trials. Similarly, the cited frequencies cannot be compared with figures obtained from other clinical investigators involving related drug products and uses, since each group of drug trials is conducted under a different set of conditions. However, the cited figures provide the physician with a basis for estimating the relative contribution of drug and nondrug factors to the incidence of side effects in the population studied.
The following tables were derived from results of two placebo-controlled efficacy trials involving Ambien CR. These trials involved patients with primary insomnia who were treated for 3 weeks with Ambien CR at doses of 12.5 mg (Table 1) or 6.25 mg (Table 2), respectively. The tables include only adverse reactions occurring at an incidence of at least 1% for Ambien CR patients and with an incidence greater than that seen in the placebo patients.
Table 1. Incidences of Treatment-Emergent Adverse Reactions in a 3-Week Placebo-Controlled Clinical Trial in Adults (percentage of patients reporting)
| Body System/Adverse Reaction |
Ambien CR
12.5 mg |
Placebo |
|---|
|
(N = 102) |
(N = 110) |
|---|
|
| Infections and infestations |
|
| Influenza |
3 |
0 |
| Gastroenteritis |
1 |
0 |
| Labyrinthitis |
1 |
0 |
| Metabolism and nutrition disorders |
|
| Appetite disorder |
1 |
0 |
| Psychiatric disorders |
|
| Hallucinations |
4 |
0 |
| Disorientation |
3 |
2 |
| Anxiety |
2 |
0 |
| Depression |
2 |
0 |
| Psychomotor retardation |
2 |
0 |
| Binge eating |
1 |
0 |
| Depersonalization |
1 |
0 |
| Disinhibition |
1 |
0 |
| Euphoric mood |
1 |
0 |
| Mood swings |
1 |
0 |
| Stress symptoms |
1 |
0 |
| Nervous system disorders |
|
| Headache |
19 |
16 |
| Somnolence |
15 |
2 |
| Dizziness |
12 |
5 |
| Memory disorders |
3 |
0 |
| Balance disorder |
2 |
0 |
| Disturbance in attention |
2 |
0 |
| Hypoesthesia |
2 |
1 |
| Ataxia |
1 |
0 |
| Paresthesia |
1 |
0 |
| Eye disorders |
|
| Visual disturbance |
3 |
0 |
| Eye redness |
2 |
0 |
| Vision blurred |
2 |
1 |
| Altered visual depth perception |
1 |
0 |
| Asthenopia |
1 |
0 |
| Ear and labyrinth disorders |
|
| Vertigo |
2 |
0 |
| Tinnitus |
1 |
0 |
| Respiratory, thoracic and mediastinal disorders |
|
|
| Throat irritation |
1 |
0 |
| Gastrointestinal disorders |
|
|
| Nausea |
7 |
4 |
| Constipation |
2 |
0 |
| Abdominal discomfort |
1 |
0 |
| Abdominal tenderness |
1 |
0 |
| Frequent bowel movements |
1 |
0 |
Gastroesophageal reflux
disease |
1 |
0 |
| Vomiting |
1 |
0 |
| Skin and subcutaneous tissue disorders |
|
|
| Rash |
1 |
0 |
| Skin wrinkling |
1 |
0 |
| Urticaria |
1 |
0 |
| Musculoskeletal and connective tissue disorders |
|
|
| Back pain |
4 |
3 |
| Myalgia |
4 |
0 |
| Neck pain |
1 |
0 |
| Reproductive system and breast disorders |
|
|
| Menorrhagia |
1 |
0 |
| General disorders and administration site conditions |
|
|
| Fatigue |
3 |
2 |
| Asthenia |
1 |
0 |
| Chest discomfort |
1 |
0 |
| Investigations |
|
|
| Blood pressure increased |
1 |
0 |
| Body temperature increased |
1 |
0 |
| Injury, poisoning and procedural complications |
|
|
| Contusion |
1 |
0 |
| Social circumstances |
|
|
| Exposure to poisonous plant |
1 |
0 |
Table 2. Incidences of Treatment-Emergent Adverse Reactions in a 3-Week Placebo-Controlled Clinical Trial in Elderly (percentage of patients reporting)
| Body System/Adverse Reaction |
Ambien CR |
Placebo |
|---|
6.25 mg
(N=99) |
(N=106) |
|---|
|
| Infections and infestations |
| Nasopharyngitis |
6 |
4 |
| Lower respiratory tract infection |
1 |
0 |
| Otitis externa |
1 |
0 |
| Upper respiratory tract infection |
1 |
0 |
| Psychiatric disorders |
|
| Anxiety |
3 |
2 |
| Psychomotor retardation |
2 |
0 |
| Apathy |
1 |
0 |
| Depressed mood |
1 |
0 |
| Nervous system disorders |
|
| Headache |
14 |
11 |
| Dizziness |
8 |
3 |
| Somnolence |
6 |
5 |
| Burning sensation |
1 |
0 |
| Dizziness postural |
1 |
0 |
| Memory disorders |
1 |
0 |
| Muscle contractions involuntary |
1 |
0 |
| Paresthesia |
1 |
0 |
| Tremor |
1 |
0 |
| Cardiac disorders |
|
| Palpitations |
2 |
0 |
| Respiratory, thoracic and mediastinal disorders |
|
| Dry throat |
1 |
0 |
| Gastrointestinal disorders |
|
| Flatulence |
1 |
0 |
| Vomiting |
1 |
0 |
| Skin and subcutaneous tissue disorders |
|
| Rash |
1 |
0 |
| Urticaria |
1 |
0 |
| Musculoskeletal and connective tissue disorders |
|
|
| Arthralgia |
2 |
0 |
| Muscle cramp |
2 |
1 |
| Neck pain |
2 |
0 |
| Renal and urinary disorders |
|
|
| Dysuria |
1 |
0 |
| Reproductive system and breast disorders |
|
|
| Vulvovaginal dryness |
1 |
0 |
| General disorders and administration site conditions |
|
|
| Influenza like illness |
1 |
0 |
| Pyrexia |
1 |
0 |
| Injury, poisoning and procedural complications |
|
|
| Neck injury |
1 |
0 |
Dose relationship for adverse reactions: There is evidence from dose comparison trials suggesting a dose relationship for many of the adverse reactions associated with zolpidem use, particularly for certain CNS and gastrointestinal adverse events.
Other adverse reactions observed during the premarketing evaluation of Ambien CR: Other treatment-emergent adverse reactions associated with participation in Ambien CR studies (those reported at frequencies of <1%) were not different in nature or frequency to those seen in studies with immediate-release zolpidem tartrate, which are listed below.
Adverse Events Observed During the Premarketing Evaluation of Immediate-Release Zolpidem Tartrate: Immediate-release zolpidem tartrate was administered to 3,660 subjects in clinical trials throughout the U.S., Canada, and Europe. Treatment-emergent adverse events associated with clinical trial participation were recorded by clinical investigators using terminology of their own choosing. To provide a meaningful estimate of the proportion of individuals experiencing treatment-emergent adverse events, similar types of untoward events were grouped into a smaller number of standardized event categories and classified utilizing a modified World Health Organization (WHO) dictionary of preferred terms.
The frequencies presented, therefore, represent the proportions of the 3,660 individuals exposed to zolpidem, at all doses, who experienced an event of the type cited on at least one occasion while receiving zolpidem. All reported treatment-emergent adverse events are included, except those already listed in the table above of adverse events in placebo-controlled studies, those coding terms that are so general as to be uninformative, and those events where a drug cause was remote. It is important to emphasize that, although the events reported did occur during treatment with Ambien, they were not necessarily caused by it.
Adverse events are further classified within body system categories and enumerated in order of decreasing frequency using the following definitions: frequent adverse events are defined as those occurring in greater than 1/100 subjects; infrequent adverse events are those occurring in 1/100 to 1/1,000 patients; rare events are those occurring in less than 1/1,000 patients.
Autonomic nervous system: Frequent: dry mouth. Infrequent: increased sweating, pallor, postural hypotension, syncope. Rare: abnormal accommodation, altered saliva, flushing, glaucoma, hypotension, impotence, increased saliva, tenesmus.
Body as a whole: Frequent: asthenia. Infrequent: chest pain, edema, falling, fever, malaise, trauma. Rare: allergic reaction, allergy aggravated, anaphylactic shock, face edema, hot flashes, increased ESR, pain, restless legs, rigors, tolerance increased, weight decrease.
Cardiovascular system: Infrequent: cerebrovascular disorder, hypertension, tachycardia. Rare: angina pectoris, arrhythmia, arteritis, circulatory failure, extrasystoles, hypertension aggravated, myocardial infarction, phlebitis, pulmonary embolism, pulmonary edema, varicose veins, ventricular tachycardia.
Central and peripheral nervous system: Frequent: ataxia, confusion, drowsiness, drugged feeling, euphoria, insomnia, lethargy, lightheadedness, vertigo. Infrequent: agitation, decreased cognition, detached, difficulty concentrating, dysarthria, emotional lability, hallucination, hypoesthesia, illusion, leg cramps, migraine, nervousness, paresthesia, sleeping (after daytime dosing), speech disorder, stupor, tremor. Rare: abnormal gait, abnormal thinking, aggressive reaction, apathy, appetite increased, decreased libido, delusion, dementia, depersonalization, dysphasia, feeling strange, hypokinesia, hypotonia, hysteria, intoxicated feeling, manic reaction, neuralgia, neuritis, neuropathy, neurosis, panic attacks, paresis, personality disorder, somnambulism, suicide attempts, tetany, yawning.
Gastrointestinal system: Frequent: diarrhea, dyspepsia, hiccup. Infrequent: anorexia, constipation, dysphagia, flatulence, gastroenteritis. Rare: enteritis, eructation, esophagospasm, gastritis, hemorrhoids, intestinal obstruction, rectal hemorrhage, tooth caries.
Hematologic and lymphatic system: Rare: anemia, hyperhemoglobinemia, leukopenia, lymphadenopathy, macrocytic anemia, purpura, thrombosis.
Immunologic system: Infrequent: infection. Rare: abscess herpes simplex herpes zoster, otitis externa, otitis media.
Liver and biliary system: Infrequent: abnormal hepatic function, increased SGPT. Rare: bilirubinemia, increased SGOT.
Metabolic and nutritional: Infrequent: hyperglycemia, thirst. Rare: gout, hypercholesteremia, hyperlipidemia, increased alkaline phosphatase, increased BUN, periorbital edema.
Musculoskeletal system: Infrequent: arthritis. Rare: arthrosis, muscle weakness, sciatica, tendinitis.
Reproductive system: Infrequent: menstrual disorder, vaginitis. Rare: breast fibroadenosis, breast neoplasm, breast pain.
Respiratory system: Frequent: sinusitis. Infrequent: bronchitis, coughing, dyspnea. Rare: bronchospasm, epistaxis, hypoxia, laryngitis, pneumonia.
Skin and appendages: Infrequent: pruritus. Rare: acne, bullous eruption, dermatitis, furunculosis, injection-site inflammation, photosensitivity reaction, urticaria.
Special senses: Frequent: diplopia, vision abnormal. Infrequent: eye irritation, eye pain, scleritis, taste perversion, tinnitus. Rare: conjunctivitis, corneal ulceration, lacrimation abnormal, parosmia, photopsia.
Urogenital system: Frequent: urinary tract infection. Infrequent: cystitis, urinary incontinence. Rare: acute renal failure, dysuria, micturition frequency, nocturia, polyuria, pyelonephritis, renal pain, urinary retention.
Drug Interactions
CNS-active drugs
Since the systematic evaluations of zolpidem in combination with other CNS-active drugs have been limited, careful consideration should be given to the pharmacology of any CNS-active drug to be used with zolpidem. Any drug with CNS-depressant effects could potentially enhance the CNS-depressant effects of zolpidem.
An immediate-release formulation of zolpidem tartrate was evaluated in healthy subjects in single-dose interaction studies for several CNS drugs. Imipramine in combination with zolpidem produced no pharmacokinetic interaction other than a 20% decrease in peak levels of imipramine, but there was an additive effect of decreased alertness. Similarly, chlorpromazine in combination with zolpidem produced no pharmacokinetic interaction, but there was an additive effect of decreased alertness and psychomotor performance. A study involving haloperidol and zolpidem revealed no effect of haloperidol on the pharmacokinetics or pharmacodynamics of zolpidem. The lack of a drug interaction following single-dose administration does not predict a lack following chronic administration.
An additive effect on psychomotor performance between alcohol and zolpidem was demonstrated [see Warnings and Precautions (5.5)].
A single-dose interaction study with zolpidem 10 mg and fluoxetine 20 mg at steady-state levels in male volunteers did not demonstrate any clinically significant pharmacokinetic or pharmacodynamic interactions. When multiple doses of zolpidem and fluoxetine at steady-state concentrations were evaluated in healthy females, the only significant change was a 17% increase in the zolpidem half-life. There was no evidence of an additive effect in psychomotor performance.
Following five consecutive nightly doses of zolpidem 10 mg in the presence of sertraline 50 mg (17 consecutive daily doses, at 7:00 am, in healthy female volunteers), zolpidem Cmax was significantly higher (43%) and Tmax was significantly decreased (53%). Pharmacokinetics of sertraline and N-desmethylsertraline were unaffected by zolpidem.
Drugs that affect drug metabolism via cytochrome P450
Some compounds known to inhibit CYP3A may increase exposure to zolpidem. The effect of inhibitors of other P450 enzymes has not been carefully evaluated.
A randomized, double-blind, crossover interaction study in ten healthy volunteers between itraconazole (200 mg once daily for 4 days) and a single dose of zolpidem (10 mg) given 5 hours after the last dose of itraconazole resulted in a 34% increase in AUC0–∞ of zolpidem. There were no significant pharmacodynamic effects of zolpidem on subjective drowsiness, postural sway, or psychomotor performance.
A randomized, placebo-controlled, crossover interaction study in eight healthy female subjects between five consecutive daily doses of rifampin (600 mg) and a single dose of an immediate-release formulation of zolpidem tartrate (20 mg) given 17 hours after the last dose of rifampin showed significant reductions of the AUC (–73%), Cmax (–58%), and T1/2 (–36%) of zolpidem together with significant reductions in the pharmacodynamic effects of zolpidem.
A randomized double-blind crossover interaction study in twelve healthy subjects showed that co-administration of a single 5 mg dose of immediate-release zolpidem tartrate with ketoconazole, a potent CYP3A4 inhibitor, given as 200 mg twice daily for 2 days increased Cmax of zolpidem by a factor of 1.3 and increased the total AUC of zolpidem by a factor of 1.7 compared to zolpidem alone and prolonged the elimination half-life by approximately 30% along with an increase in the pharmacodynamic effects of zolpidem. Caution should be used when ketoconazole is given with zolpidem and consideration should be given to using a lower dose of zolpidem when ketoconazole and zolpidem are given together. Patients should be advised that use of Ambien CR with ketoconazole may enhance the sedative effects.
Other drugs with no interaction with zolpidem
A study involving cimetidine/zolpidem and ranitidine/zolpidem combinations revealed no effect of either drug on the pharmacokinetics or pharmacodynamics of zolpidem.
Zolpidem had no effect on digoxin pharmacokinetics and did not affect prothrombin time when given with warfarin in normal subjects.
Drug-laboratory test interactions
Zolpidem is not known to interfere with commonly employed clinical laboratory tests. In addition, clinical data indicate that zolpidem does not cross-react with benzodiazepines, opiates, barbiturates, cocaine, cannabinoids, or amphetamines in two standard urine drug screens.
USE IN SPECIFIC POPULATIONS
Pregnancy
Pregnancy Category C
There are no adequate and well-controlled studies of Ambien CR in pregnant women. Ambien CR should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.
Administration of zolpidem to pregnant rats and rabbits resulted in adverse effects on offspring development at doses greater than the Ambien CR maximum recommended human dose (MRHD) of 12.5 mg/day (approximately 10 mg/day zolpidem base); however, teratogenicity was not observed.
When zolpidem was administered at oral doses of 4, 20, and 100 mg base/kg (approximately 4, 20 and 100 times the MRHD on a mg/m2 basis) to pregnant rats during the period of organogenesis, dose-related decreases in fetal skull ossification occurred at all but the lowest dose, which is approximately 4 times the MRHD on a mg/m2 basis. In rabbits treated during organogenesis with zolpidem at oral doses of 1, 4, and 16 mg base/kg (approximately 2, 8 and 30 times the MRHD on a mg/m2 basis), increased embryo-fetal death and incomplete fetal skeletal ossification occurred at the highest dose. The no-effect dose for embryo-fetal toxicity in rabbits is approximately 8 times the MRHD on a mg/m2 basis. Administration of zolpidem to rats at oral doses of 4, 20, and 100 mg base/kg (approximately 4, 20 and 100 times the MRHD on a mg/m2 basis) during the latter part of pregnancy and throughout lactation produced decreased offspring growth and survival at all but the lowest dose, which is approximately 4 times the MRHD on a mg/m2 basis.
Neonatal complications
Studies in children to assess the effects of prenatal exposure to zolpidem have not been conducted; however, cases of severe neonatal respiratory depression have been reported when zolpidem was used at the end of pregnancy, especially when taken with other CNS depressants.
Children born to mothers taking sedative-hypnotic drugs may be at some risk for withdrawal symptoms during the postnatal period. Neonatal flaccidity has been reported in infants born to mothers who received sedative-hypnotic drugs during pregnancy.
Labor and delivery
Ambien CR has no established use in labor and delivery [see Pregnancy (8.1)].
Nursing mothers
Zolpidem is excreted in human milk. Studies in lactating mothers indicate that the half-life of zolpidem is similar to that in non-lactating women (2.6 ± 0.3 hr). The effect of zolpidem on the nursing infant is not known. Caution should be exercised when Ambien CR is administered to a nursing woman.
Pediatric use
Safety and effectiveness of zolpidem have not been established in pediatric patients.
In an 8-week controlled study, 201 pediatric patients (aged 6–17 years) with insomnia associated with attention-deficit/hyperactivity disorder (90% of the patients were using psychoanaleptics), were treated with an oral solution of zolpidem (n=136), or placebo (n = 65). Zolpidem did not significantly decrease latency to persistent sleep, compared to placebo, as measured by polysomnography after 4 weeks of treatment. Psychiatric and nervous system disorders comprised the most frequent (> 5%) treatment emergent adverse reactions 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%) [see Warnings and Precautions (5.6)]. Ten patients on zolpidem (7.4%) discontinued treatment due to an adverse reaction.
FDA has not required pediatric studies of Ambien CR in the pediatric population based on these efficacy and safety findings.
Geriatric use
A total of 99 elderly (≥ 65 years of age) received daily doses of 6.25 mg Ambien CR in a 3-week placebo-controlled study. The adverse reaction profile of Ambien CR 6.25 mg in this population was similar to that of Ambien CR 12.5 mg in younger adults (≤ 64 years of age). Dizziness was reported in 8% of Ambien CR-treated patients compared with 3% of those treated with placebo.
The dose of Ambien CR in elderly patients is 6.25 mg to minimize adverse effects related to impaired motor and/or cognitive performance and unusual sensitivity to sedative/hypnotic drugs [see Warnings and Precautions (5.6)].
