Your doctor may suggest Rozerem if your sleep-wake cycle seems out of whack.

Your doctor may suggest Rozerem if your sleep-wake cycle seems out of whack.(TOM GRILL/CORBIS)In 2005 the FDA approved Rozerem (generic name ramelteon), a prescription sleep aid different from any existing drug on the market. While hypnotic medications work to slow down the central nervous system, Rozerem instead mimics melatonin, a chemical that helps regulate the body's natural sleep-wake cycle. Because of its unique mechanism, this drug has its own set of pros and cons to consider.

Because clinical studies of Rozerem have found little evidence for abuse and tolerance (it was tested in patients with a history of drug abuse), it's the only prescription sleep medication not classified as a controlled substance by the U.S. Drug Enforcement Agency. This means it's easier for doctors to prescribe long-term than other prescription sleep aids.

The idea may be encouraging, but in reality all sleep aids have very little abuse risk for most patients. Rozerem also costs more than older benzodiazepine medications, since it is not yet available as a generic.

The scientists behind Rozerem's development explain that by targeting melatonin receptors—which are responsible for the brain's sleep-wake cycle—it may avoid the groggy side effects of sedative drugs, which work by slowing down the central nervous system. A company representative has compared taking Rozerem to shutting down a computer the right way, whereas using other medications is like pulling the plug so that the reboot process takes longer.

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But in clinical trials Rozerem still caused side effects, such as daytime sleepiness and dizziness, in a small percentage of people. It has also been associated with altered hormonal levels, which may cause sexual side effects. Rozerem has not been studied in patients with sleep apnea or related breathing disorders.

The real question about Rozerem, though, is how well it works. In a 2006 government-sponsored analysis, it performed slightly worse than hypnotic medications; patients fell asleep seven to 16 minutes faster and slept 11 to 19 minutes longer than they did with a placebo.

Rozerem, like its over-the-counter relative, melatonin, works as a chronobiotic, explains Matthew Ebben, PhD, a sleep specialist at the Weill Cornell Medical College. "It may work for someone who needs to have their circadian rhythms shifted—if someone's internal clock got messed up because of jet lag, and they want to sleep at all the wrong times, for example," he says.

"It's also being studied in blind people who lack the environmental cues—light and dark—that the body uses to naturally transition into sleep. But for people who just aren't sleepy at all, traditional insomniacs, it's unclear whether Rozerem really makes much of a difference."

One benefit of Rozerem over OTC melatonin: The prescription medication is held to high standards in terms of ingredients and strength of the product, whereas supplements are not regulated by the FDA and there's no way to verify their contents.