New Sleep Drug May Cause Fewer Side Effects

(Ivanhoe Newswire) -- A new kind of sleep medication may not cause the typical behavioral side effects, such as dependence and abuse, as other sleep drugs.

Researchers from the University of Texas Health Science Center in San Antonio tested the recently-approved prescription sleep drug ramelteon (Rozerem) in monkeys. Results show the drug may spare patients short-term and long-term effects of other sleep aids.

Ramelteon targets the brain's melatonin receptors rather than its benzodiazepine receptors, which may make its side effects different from those of old and new sedative hypnotics. Standard sleep aids bind to the brain's benzodiazepine receptors and can cause impaired thinking, withdrawal symptoms, and rebound insomnia.

Researchers conducted three experiments in monkeys to make their conclusions. In one experiment, they measured clinical behavior, learned behavior, and blood levels of the drug to determine whether the monkeys had become dependent on the drug after they stopped taking it. They did not observe 10 of the 33 usual withdrawal-related signs of dependence, including teeth grinding, biting fingernails, shakes and tremors.

The authors conclude, "Ramelteon does not likely share subjective effects with benzodiazepines in humans and thus, should not be expected to share abuse liability with BzRAs [benzodiazepine receptor agonists]."

The study was funded by Takeda Pharmaceutical Company Limited, which markets ramelteon as Rozerem.

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SOURCE: Behavioral Neuroscience, 2006;120:535-541