Continue Learning with FreeCME
Clinician.com and FreeCME Account Successfully Created
Your new Clinician account also gives you access to FreeCME, where you can take free accredited for CE credit
The FDA has approved an extended-release form of zolpidem. The drug delivery system consists of a coated 2-layer tablet, one releases the drug immediately and the other provides a slower release. Zolpidem extended-release (zolpidem ER) is marketed by Sanofi-Synthelabo as Ambien CR.
Pharmacology Update: Zolpidem Tartrate Extended Release Tablets (Ambien CR)
October 30, 2005 3 minutes read
Pharmacology Update
Zolpidem Tartrate Extended Release Tablets (Ambien CR™)
By William T. Elliott, MD, FACP, and James Chan, PhD, PharmD. Dr. Elliott is Chair, Formulary Committee, Northern California Kaiser Permanente; Associate Clinical Professor of Medicine, University of California, San Francisco; Dr. Chan is Pharmacy Quality and Outcomes Manager, Kaiser Permanente, Oakland. Drs. Chan and Elliott report no financial relationships to this field of study.
The FDA has approved an extended-release form of zolpidem. The drug delivery system consists of a coated 2-layer tablet, one releases the drug immediately and the other provides a slower release. Zolpidem extended-release (zolpidem ER) is marketed by Sanofi-Synthelabo as Ambien CR™.
Indications
Zolpidem ER is indicated for the treatment of insomnia characterized by difficulty falling asleep and/or difficulty staying asleep.1
Dosage
The recommended dose is 12.5 mg immediately before bedtime. As with the immediate-release formulation, zolpidem should not be taken with or immediately after a meal.1,2 The tablet should be swallowed whole and not divided, chewed, or crushed. The 6.25 mg dose is recommended for the elderly, debilitated, or those with hepatic insufficiency.1
Zolpidem ER is available as 6.25 mg and 12.5 mg tablets.
Potential Advantages
The duration of effect may be longer with zolpidem ER compared to the immediate-release formulation.
Potential Disadvantages
The longer systemic exposure to the drug potentially could lead to greater daytime residual effects.
Comments
Zolpidem is a nonbenzodiazepine sedative hypnotic with selective binding for the 1 subunit of the GABA(A) receptor (ie, benzodiazepine 1 receptor) and generally does not alter sleep architecture.3,4 It reduces sleep latency and increases total sleep time and is generally well tolerated.4 The extended-release formulation is marketed at 25% higher dose (ie, 12.5 mg and 6.25 mg vs 10 mg and 5 mg). This combined with the extended-release formulation provides a higher systemic exposure to the drug and a delay of about an hour to reach the same plasma level compared with the immediate-release formulation. The 2 formulations have similar elimination half lives.1 The efficacy of zolpidem extended-release was shown in two placebo-controlled, 3-week studies in adult patients with primary insomnia. One study used 12.5 mg in patients aged 18-64 (n = 212) and the other used 6.25 mg in elderly patients (> 65 yrs) (n = 205). In the assessment of next-day residual effects, next-day somnolence was reported in 15% of zolpidem ER patients compared to 2% for placebo. There were no published studies comparing the 2 formulations. The wholesale cost of zolpidem ER is $2.82 per tablet for both strengths.
Clinical Implications
As the patent of zolpidem approaches expiration, the manufacturer has introduced an extended-release formulation in an attempt to maintain market share of the most commonly prescribed sleeping aid. Zolpidem ER does not appear to offer any substantive clinical advantages over the immediate-release formulation that is expected to be available generically later in 2006.
References
1. Ambien CR™ product information. Sanofi-Synthelabo Inc. August, 2005.
2. Ambien product information. Sanofi-Synthelabo Inc. March, 2004.
3. Holm KJ, Goa KL. Zolpidem: an update of its pharmacology, therapeutic efficacy and tolerability in the treatment of insomnia. Drugs. 2000;59:865-889.
4. Swainston Harrison T, Keating GM. Zolpidem: a review of its use in the management of insomnia. CNS Drugs. 2005;19:65-89.
The FDA has approved an extended-release form of zolpidem. The drug delivery system consists of a coated 2-layer tablet, one releases the drug immediately and the other provides a slower release. Zolpidem extended-release (zolpidem ER) is marketed by Sanofi-Synthelabo as Ambien CR.Article Limit Reached
You have reached your article limit for the month. Subscribe now to access this article plus other member-only content.
- Award-winning Medical Content
- Latest Advances & Development in Medicine
- Unbiased Content