*Reactions reported by at least 1% of patients treated with zolpidem tartrate and at a greater frequency than placebo.
The following table was derived from results of three placebo-controlled long-term efficacy trials involving zolpidem tartrate. These trials involved patients with chronic insomnia who were treated for 28 to 35 nights with zolpidem at doses of 5, 10, or 15 mg. The table is limited to data from doses up to and including 10 mg, the highest dose recommended for use. The table includes only adverse events occurring at an incidence of at least 1% for zolpidem patients.
- Table 2: Incidences of Treatment-Emergent Adverse Experiences in Placebo-Controlled Clinical Trials Lasting up to 35 Nights (percentage of patients reporting)
Table 2: Incidences of Treatment-Emergent Adverse Experiences in Placebo-Controlled Clinical Trials Lasting up to 35 Nights (percentage of patients reporting)Body System Adverse Event* | Zolpidem (≤10 mg) (N=152) | Placebo (N=161) |
|---|
Autonomic Nervous System | | |
Dry mouth | 3 | 1 |
Body as a Whole | | |
Allergy | 4 | 1 |
Back pain | 3 | 2 |
Influenza-like symptoms | 2 | - |
Chest pain | 1 | - |
Cardiovascular System | | |
Palpitation | 2 | - |
Central and Peripheral Nervous System | | |
Drowsiness | 8 | 5 |
Dizziness | 5 | 1 |
Lethargy | 3 | 1 |
Drugged feeling | 3 | - |
Lightheadedness | 2 | 1 |
Depression | 2 | 1 |
Abnormal dreams | 1 | - |
Amnesia | 1 | - |
Sleep disorder | 1 | - |
Gastrointestinal System | | |
Diarrhea | 3 | 2 |
Abdominal pain | 2 | 2 |
Constipation | 2 | 1 |
Respiratory System | | |
Sinusitis | 4 | 2 |
Pharyngitis | 3 | 1 |
Skin and Appendages | | |
Rash
| 2 | 1 |
*Reactions reported by at least 1% of patients treated with zolpidem tartrate and at a greater frequency than placebo.
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.
Adverse Event Incidence Across the Entire Preapproval Database
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 zolpidem tartrate, 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
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:edema, falling, fatigue, 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, euphoria, headache, insomnia, vertigo
Infrequent:agitation, anxiety, 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:dyspepsia, hiccup, nausea.
Infrequent:anorexia, constipation, dysphagia, flatulence, gastroenteritis, vomiting.
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
Frequent:arthralgia, myalgia.
Infrequent:arthritis.
Rare:arthrosis, muscle weakness, sciatica, tendinitis.
Reproductive System
Infrequent:menstrual disorder, vaginitis.
Rare:breast fibroadenosis, breast neoplasm, breast pain.
Respiratory System
Frequent:upper respiratory infection, lower respiratory infection.
Infrequent:bronchitis, coughing, dyspnea, rhinitis.
Rare:bronchospasm, respiratory depression, 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.
CYP3A4 Inducers
Rifampin
Rifampin, a CYP3A4 inducer, significantly reduced the exposure to and the pharmacodynamic effects of zolpidem. Use of rifampin in combination with zolpidem may decrease the efficacy of zolpidem and is not recommended
[see
Clinical Pharmacology (
12.3)].
St. John’s wort
Use of St. John’s wort, a CYP3A4 inducer, in combination with zolpidem may decrease blood levels of zolpidem and is not recommended.
CYP3A4 Inhibitors
Ketoconazole
Ketoconazole, a potent CYP3A4 inhibitor, increased the exposure to and pharmacodynamic effects of zolpidem. Consideration should be given to using a lower dose of zolpidem when a potent CYP3A4 inhibitor and zolpidem are given together
[see Clinical Pharmacology (
12.3)].
Special Populations
Elderly
In the elderly, the dose for zolpidem tartrate should be 5 mg
[see
Warnings and Precautions (
5), Dosage and Administration (
2)].
This recommendation is based on several studies in which the mean C
max, T
1/2, and AUC were significantly increased when compared to results in young adults. In one study of eight elderly subjects (> 70 years), the means for C
max, T
1/2, and AUC significantly increased by 50% (255 vs 384 ng/mL), 32% (2.2 vs 2.9 hr), and 64% (955 vs 1,562 ng∙hr/mL), respectively, as compared to younger adults (20 to 40 years) following a single 20 mg oral dose. Zolpidem tartrate did not accumulate in elderly subjects following nightly oral dosing of 10 mg for 1 week.
Hepatic Impairment
The pharmacokinetics of zolpidem tartrate in eight patients with chronic hepatic insufficiency was compared to results in healthy subjects. Following a single 20 mg oral zolpidem tartrate dose, mean C
maxand AUC were found to be two times (250 vs 499 ng/mL) and five times (788 vs 4,203 ng∙hr/mL) higher, respectively, in hepatically compromised patients. T
maxdid not change. The mean half-life in cirrhotic patients of 9.9 hr (range: 4.1 to 25.8 hr) was greater than that observed in normal subjects of 2.2 hr (range: 1.6 to 2.4 hr)
[see Dosage and Administration (
2.2), Warnings and Precautions (
5.8), Use in Specific Populations (
8.7)
].
Renal Impairment
The pharmacokinetics of zolpidem tartrate was studied in 11 patients with end-stage renal failure (mean Cl
Cr= 6.5 ± 1.5 mL/min) undergoing hemodialysis three times a week, who were dosed with zolpidem tartrate 10 mg orally each day for 14 or 21 days. No statistically significant differences were observed for C
max, T
max, half-life, and AUC between the first and last day of drug administration when baseline concentration adjustments were made. Zolpidem was not hemodialyzable. No accumulation of unchanged drug appeared after 14 or 21 days. Zolpidem pharmacokinetics was not significantly different in renally impaired patients. No dosage adjustment is necessary in patients with compromised renal function.
Drug Interactions
CNS Depressants
Co-administration of zolpidem with other CNS depressants increases the risk of CNS depression
[see
Warnings and Precautions (
5.2)].Zolpidem tartrate was evaluated in healthy volunteers 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 the absence of an effect following chronic administration.
An additive adverse effect on psychomotor performance between alcohol and oral zolpidem was demonstrated
[see
Warnings and Precautions (
5.2)].
Following five consecutive nightly doses at bedtime of oral zolpidem tartrate 10 mg in the presence of sertraline 50 mg (17 consecutive daily doses, at 7:00 am, in healthy female volunteers), zolpidem C
maxwas significantly higher (43%) and T
maxwas significantly decreased (-53%). Pharmacokinetics of sertraline and N-desmethylsertraline were unaffected by zolpidem.
A single-dose interaction study with zolpidem tartrate 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 were given at steady state and the concentrations evaluated in healthy females, an increase in the zolpidem half-life (17%) was observed. There was no evidence of an additive effect in psychomotor performance.
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 on the pharmacokinetics of zolpidem is unknown.
A single-dose interaction study with zolpidem tartrate 10 mg and itraconazole 200 mg at steady-state levels in male volunteers resulted in a 34% increase in AUC
0–∞of zolpidem tartrate. There were no pharmacodynamic effects of zolpidem detected on subjective drowsiness, postural sway, or psychomotor performance.
A single-dose interaction study with zolpidem tartrate 10 mg and rifampin 600 mg at steady-state levels in female subjects showed significant reductions of the AUC (-73%), C
max(-58%), and T
1/2(-36 %) of zolpidem together with significant reductions in the pharmacodynamic effects of zolpidem tartrate. Rifampin, a CYP3A4 inducer, significantly reduced the exposure to and the pharmacodynamic effects of zolpidem
[see Drug Interactions (
7.2)].
Similarly, St. John’s wort, a CYP3A4 inducer, may also decrease the blood levels of zolpidem.
A single-dose interaction study with zolpidem tartrate 5 mg and ketoconazole, a potent CYP3A4 inhibitor, given as 200 mg twice daily for 2 days increased C
maxof zolpidem (30%) and the total AUC of zolpidem (70%) compared to zolpidem alone and prolonged the elimination half-life (30 %) along with an increase in the pharmacodynamic effects of zolpidem
[see Drug Interactions (
7.2)].
Additionally, fluvoxamine (a strong inhibitor of CYP1A2 and a weak inhibitor of CYP3A4 and CYP2C9) and ciprofloxacin (a strong inhibitor of CYP1A2 and a moderate inhibitor of CYP3A4) are also likely to inhibit zolpidem’s metabolic pathways, potentially leading to an increase in zolpidem exposure.
Other Drugs with No Interactions with Zolpidem
A study involving cimetidine/zolpidem tartrate and ranitidine/zolpidem tartrate combinations revealed no effect of either drug on the pharmacokinetics or pharmacodynamics of zolpidem.
Zolpidem tartrate had no effect on digoxin pharmacokinetics and did not affect prothrombin time when given with warfarin in healthy subjects.
Carcinogenesis
Zolpidem was administered to mice and rats for 2 years at oral doses of 4, 18, and 80 mg base/kg/day. In mice, these doses are approximately 2.5, 10, and 50 times the MRHD of 10 mg/day (8 mg zolpidem base) based on mg/m
2body surface area and in rats, these doses are approximately 5, 20, and 100 times the MRHD based on mg/m
2body surface area. No evidence of carcinogenic potential was observed in mice. In rats, renal tumors (lipoma, liposarcoma) were seen at the mid and high doses.
Mutagenesis
Zolpidem was negative in
in vitro(bacterial reverse mutation, mouse lymphoma, and chromosomal aberration) and
in vivo(mouse micronucleus) genetic toxicology assays.
Impairment of Fertility
Zolpidem was administered to rats at 4, 20, and 100 mg base/kg/day, which are approximately 5, 25, and 120 times the MRHD of 10 mg/day (8 mg zolpidem base) based on mg/m
2body surface area, prior to and during mating, and continuing in females through postpartum day 25. Zolpidem caused irregular estrus cycles and prolonged precoital intervals at the highest dose tested, which is approximately 120 times the MRHD based on mg/m2 body surface area. The NOAEL for these effects is 25 times the MRHD based on a mg/m
2body surface area. There was no impairment of fertility at any dose tested.
Next-Day Residual Effects
Next-day residual effects of zolpidem tartrate were evaluated in seven studies involving normal subjects. In three studies in adults (including one study in a phase advance model of transient insomnia) and in one study in elderly subjects, a small but statistically significant decrease in performance was observed in the Digit Symbol Substitution Test (DSST) when compared to placebo. Studies of zolpidem tartrate in non-elderly patients with insomnia did not detect evidence of next-day residual effects using the DSST, the Multiple Sleep Latency Test (MSLT), and patient ratings of alertness.
Rebound Effects
There was no objective (polysomnographic) evidence of rebound insomnia at recommended doses seen in studies evaluating sleep on the nights following discontinuation of zolpidem tartrate. There was subjective evidence of impaired sleep in the elderly on the first post-treatment night at doses above the recommended elderly dose of 5 mg.
Memory Impairment
Controlled studies in adults utilizing objective measures of memory yielded no consistent evidence of next-day memory impairment following the administration of zolpidem tartrate. However, in one study involving zolpidem doses of 10 and 20 mg, there was a significant decrease in next-morning recall of information presented to subjects during peak drug effect (90 minutes post dose), i.e., these subjects experienced anterograde amnesia. There was also subjective evidence from adverse event data for anterograde amnesia occurring in association with the administration of zolpidem tartrate, predominantly at doses above 10 mg.
Effects on Sleep Stages
In studies that measured the percentage of sleep time spent in each sleep stage, zolpidem tartrate has generally been shown to preserve sleep stages. Sleep time spent in stages 3 and 4 (deep sleep) was found comparable to placebo with only inconsistent, minor changes in REM (paradoxical) sleep at the recommended dose.