Zolpidem is a prescription drug used for the short-term treatment of insomnia (sleeping pill). It works quickly (usually within 15 minutes) and has a short half-life (2-3 hours), but will last longer in patients with hepatic failure. Some trade names of zolpidem are Ambien®, Stilnox®, Stilnoct®, or Myslee®.^[1] Its sedative effects are similar to those of the benzodiazepines, but it is actually classified as an imidazopyridine, and the anticonvulsant and muscle relaxant effects only appear at 10 and 20 times the dose required for sedation, respectively.^[2] For that reason, it has never been approved for either muscle relaxation or seizure prevention. Such drastically increased doses are likely to induce one or more negative side effects, including hallucinations and/or amnesia.

The patent on zolpidem is held by the French pharmacutical corporation Sanofi-Aventis.

Uses

Zolpidem is approved for the short-term treatment of insomnia, but it has been studied for nightly use up to six months in a single-blind, open-label trial published in 1991,^[3] an open-label study lasting 180 days published in 1992 (with continued efficacy in patients who had kept taking it as of 180 days after the end of the trial),^[4] and in an open-label trial lasting 179 days published in 1993.^[5]

The United States Air Force uses zolpidem under trade name Ambien® as "no-go pills" to help the pilots sleep after the mission; another drug used for the same purpose is temazepam (Restoril®).^[6] (Cf. the "go-pills", amphetamine served under the name Dexedrine® as a stimulant for the pilots, or its recent modafinil (Provigil®) replacement).^[7]

It is also used off-label to treat restless leg syndrome.^[8]

As is the case with many prescription sedative/hypnotic drugs, zolpidem is sometimes used by stimulant users to "come down" after the use of stimulants such as methamphetamine, cocaine, methylenedioxymethamphetamine (MDMA), or pharmaceutical amphetamines.^[9]

Mechanism of action

In 1990, Pritchett and Seeburg noted that zolpidem binds with high affinity to the α₁-, and with medium affinity to the α₂- and α₃-GABA_A receptor subunits, and found that it had no affinity for the α₅ subunit.^[10] Two years later, zolpidem was noted to have a high affinity for ω₁-benzodiazepine receptors, a low affinity for ω₂ and a very low affintity for ω₃, respectively by Ruano et al in 1992.^[11] In other words, it has the highest affinity for ω₁ binding sites on α-₁GABA_A receptor subunits, and it is this that mediates its sedative and weak anticonvulsant properties.^[12]

Abuse

Abuse of this drug (specifically the Ambien brand) is becoming more common in young people. Abusers claim that 'fighting' the effects of the drug by forcing yourself to stay awake will cause vivid visuals and a body high (see side-effects below.)

Side-effects

Larger doses of the drug can result in a variety of unwanted side effects: hallucinations, delusions, poor motor coordination, euphoria (though many instead report dysphoric reactions) increased appetite, increased sex drive, poor judgement, and, following use, inability to remember events that took place while under the influence of the drug (anterograde amnesia). Some users take zolpidem recreationally for these side effects, however, it is not as common as with the benzodiazepines because of its unique mental imagery (which can distract the user from reality without actually producing genuine hallucinations) and irrational behaviour combined with the amnesia. Accordingly, Zolpidem can also become psychologically addictive if taken for extended periods of time, due to dependence on its ability to put one to sleep or to the unique sense of euphoria it can produce. Under the influence of the drug it is common to take more zolpidem than is necessary due to forgetting that one has already taken a pill. Users are advised to keep additional zolpidem away to avoid this risk.

See also

• alpidem

References and notes

• Ambien.com (2005) AMBIEN® Prescribing Information, Information About a Short-term Treatment for Insomnia - Ambien.com Home Page for Health-care Professionals [online] Sanofi-Synthelabo Inc. New York, NY 10016. Available from: http://www.ambien.com/hcp/index.asp Accessed on 27 July 2005.
• STILNOX (zolpidem tartrate) PRODUCT INFORMATION Sanofi-Synthelabo Australia Pty Limited. 15 April 2004.

1. ^  Myslee® (zolpidem) to be launched in Japan Press Releases. Paris, December 11, 2000. Sanofi-Aventis.
2. ^  Depoortere H, Zivkovic B, Lloyd KG, Sanger DJ, Perrault G, Langer SZ, Bartholini G. "Zolpidem, a novel nonbenzodiazepine hypnotic. I. Neuropharmacological and behavioral effects." Journal of Pharmacology and Experimental Therapeutics. 1986 May;237(2):649-58. PMID 2871178
3. ^  Schlich D, L'Heritier C, Coquelin JP, Attali P, Kryrein HJ. "Long-term treatment of insomnia with zolpidem: a multicentre general practitioner study of 107 patients." J Int Med Res. 1991 May-Jun;19(3):271-9. PMID 1670039
4. ^  Maarek L, Cramer P, Attali P, Coquelin JP, Morselli PL. "The safety and efficacy of zolpidem in insomniac patients: a long-term open study in general practice." J Int Med Res. 1992 Apr;20(2):162-70. PMID 1521672
5. ^  Kummer J, Guendel L, Linden J, Eich FX, Attali P, Coquelin JP, Kyrein HJ. "Long-term polysomnographic study of the efficacy and safety of zolpidem in elderly psychiatric in-patients with insomnia." J Int Med Res. 1993 Jul-Aug;21(4):171-84. PMID 8112475
6. ^  Caldwell JA, Caldwell JL. "Fatigue in military aviation: an overview of US military-approved pharmacological countermeasures." Aviation, Space, and Environmental Medicine. 2005 Jul;76(7 Suppl):C39-51. PMID 16018329
7. ^  see Caldwell et al., 1993.
8. ^  Evidente, Virgilio Gerald H., Caviness, John N., and Adler, Charles H. "Case Studies in Movement Disorders." Seminars in Neurology. 23(3):277-284, 2003. Thieme Medical Publishers. 26 Jan 2004. Medscape Fulltext Thieme Fulltext PMID 14722823
9. ^  Pritchett DB, Seeburg PH. "Gamma-aminobutyric acidA receptor alpha 5-subunit creates novel type II benzodiazepine receptor pharmacology." Journal of Neurochemistry. 1990 May;54(5):1802-4. PMID 2157817
10. ^  Ruano D, Vizuete M, Cano J, Machado A, Vitorica J. "Heterogeneity in the allosteric interaction between the gamma-aminobutyric acid (GABA) binding site and three different benzodiazepine binding sites of the GABAA/benzodiazepine receptor complex in the rat nervous system." Journal of Neurochemistry. 1992 Feb;58(2):485-93. PMID 1309562
11. ^  Crestani F, Martin JR, Mohler H, Rudolph U. "Mechanism of action of the hypnotic zolpidem in vivo." British Journal of Pharmacology. 2000 Dec;131(7):1251-4. PMID 11090095 Fulltext
12. ^  Angelettie M.S.W., Lisa. "Ambien Abuse" Fulltextde:Zolpidem