Silenor
A First of its Kind Prescription Sleep Medicine for People with Insomnia Who Have Trouble Staying Asleep

A Summary of Key Facts About Silenor

• In March 2010, the U.S. Food and Drug Administration (FDA) approved Silenor, Somaxon's prescription sleep aid, for the treatment of insomnia characterized by difficulty with sleep maintenance.
  • Sleep maintenance difficulties, defined as waking frequently during the night and/or waking too early and being unable to return to sleep, are the most commonly reported nighttime symptoms of insomnia.
• Silenor is the first and only non-scheduled prescription sleep aid that is proven to provide patients with a full night's sleep, including sleep into the 7th and 8th hour.
• Silenor is approved for use in people with chronic (long-term) or transient (short-term) insomnia characterized by difficulty with sleep maintenance. Silenor can be used for as long as recommended by the treating physician, and is approved for use in adults and in the elderly.
  • The Silenor NDA contained data from clinical trials that included more than 1,000 subjects.
• The Silenor clinical development program demonstrated a favorable safety and tolerability profile, with the overall incidence of adverse events comparable to placebo, a low discontinuation rate and no evidence of withdrawal, tolerance, amnesia or complex sleep behaviors (e.g., sleep driving, sleep eating, etc.).
  • The most commonly reported side effect was drowsiness.
  • There was no clinically meaningful evidence of next-day residual effects.
• Silenor has not been designated as a controlled substance by the U.S. Drug Enforcement Administration (DEA) because of its demonstrated lack of abuse potential. In addition, in the Silenor clinical development program, no withdrawal effects or other adverse events were observed that would indicate that Silenor produces physical dependence.
  • In Somaxon's market research, abuse potential/risk of dependency was one of the most common safety concerns cited by patients as a reason for not seeking a prescription treatment for insomnia, switching medications or discontinuing treatment.
• Somaxon's market research indicates that the clinical profile most desired by patients and doctors is that of a product that will provide 7-8 hours of sleep without causing next day sedation and without the risk of other troubling side effects such as amnesia, hallucinations and complex sleep behaviors. Importantly, they want to feel confident that their medication can be taken safely over time with no tolerance to the drug's effects and no risk of dependency.

A Distinct Mechanism of Action

• Silenor works differently than other prescription sleep aids approved to treat insomnia. Silenor binds with high affinity to the histamine H₁ receptor, where it functions to block histamine, one of several naturally occurring neurotransmitters in the brain that promote wakefulness. It is believed that the sleep maintenance effect of Silenor is due to this blockade of histamine.
• The most commonly prescribed sleep aids work by non-selectively enhancing gamma-aminobutyric acid (GABA), a sleep-promoting neurotransmitter, resulting in broad CNS depression.
  • The FDA-approved sleep aids that work via the GABA receptor system are regulated as Schedule IV controlled substances by the U.S. Drug Enforcement Agency (DEA) because they are associated with some risk of abuse.

Silenor Formulation

• Silenor is a low-dose (3 mg, 6 mg) oral tablet formulation of doxepin that is patent protected for use in insomnia.