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Silenor

Generic name: doxepin
Treatment for: Insomnia

Update: Silenor Now FDA Approved - March 17, 2010

Somaxon Pharmaceuticals’ Silenor Demonstrates Positive Results in its Third Phase 3 Clinical Trial in Insomnia

Nearly 70 million American adults are affected by insomnia – characterized by difficulty falling asleep, waking frequently during the night, waking too early and not being able to return to sleep, or waking up not feeling refreshed. The prevalence of insomnia is greater in the elderly than in adults, particularly sleep maintenance insomnia.

Results from a 2005 National Sleep Foundation Sleep in America poll reported that respondents experienced the following insomnia symptoms:

An estimated 20 to 40% of all adults complain of acute, or transient, insomnia, generally defined as a complaint lasting several days up to a couple of weeks, while 10 to 15% complain of chronic insomnia, generally defined as a complaint lasting approximately 4 weeks or longer.

About Silenor

Silenor is a low-dose (1 mg, 3 mg, 6 mg) oral tablet formulation of doxepin HCl that is patent protected for its use in insomnia. Doxepin has been prescribed for more than 35 years for the treatment of depression and anxiety at dosages typically ranging from 75 mg to 300 mg per day. At the currently prescribed high doses, doxepin is known to have a range of undesirable side effects. However, at the doses used in Silenor in controlled clinical trials completed by Somaxon to date, Silenor has been well tolerated.

Unlike most approved insomnia medications, Silenor does not act via a set of brain receptors known as the benzodiazepine, or GABA, receptors. Drugs that act on these receptors have been associated with amnesia, hallucinations, dependency and addiction. The U.S. Drug Enforcement Agency classifies these products as Schedule IV controlled substances and carefully monitors and controls their prescribing and use. Although the mechanism of action for the sleep-promoting effects of Silenor is not definitively known, it differs from the leading prescription insomnia treatments which act via GABA receptors in that the effects of Silenor are mediated through the histaminergic system. Histamine blocking has been demonstrated to reduce wakefulness and is thought to promote the initiation and maintenance of sleep.

Posted: November 2006

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