As part of the effort to develop effective behavioral and medical sleep therapies, scientists consider the potential for dependence and abuse associated with prescription sleep drugs.
This line of research has produced findings showing that a recently approved prescription sleep drug may spare users the potential for dependence and abuse found with other sleep aids. Laboratory studies of the effects of ramelteon suggest that the drug’s targeting of the brain’s melatonin receptors rather than its benzodiazepine receptors make its subjective side effects different from those of old and new sedative hypnotics. The research is reported in the June issue of Behavioral Neuroscience, which is published by the American Psychological Association (APA).
At the University of Texas Health Science Center in San Antonio, pharmacology researchers led by Charles P. France, PhD, assessed whether ramelteon instigated the same kinds of broad cognitive effects as other, more commonly prescribed sleep aids. That other group includes traditional hypnotics and newer drugs such as zaleplon (Sonata) and zolpidem (Ambien), all of which bind to the brain’s benzodiazepine receptors and may result in impaired thinking, hangover, withdrawal symptoms and rebound insomnia.
Laboratory tests and clinical studies also show that even low-dose benzodiazepines, especially in long-term use, create the potential for dependence and abuse. Says Dr. France, ”Although medication might not always be indicated for insomnia, when they are prescribed, it is essential to limit the adverse side effects as much as possible.”
The U.S. Food and Drug Administration (FDA) approved the use of ramelteon (brand name Rozerem) in July of 2005. Prior to FDA approval, Dr. France and his colleagues researched drug side effects, capitalizing on the fact that monkeys – just like humans -- can be trained to recognize the specific effects of a drug class, presumably by how they feel. Says Dr. France, “Those experienced with the ‘feeling’ of a particular drug can easily recognize when they have received that drug and can reliably detect when they have been given a drug from a different pharmacologic class.”
In one experiment, the researchers trained monkeys to press a lever only when given a benzodiazepine called midazolam (Versed). Then the team gave the monkeys ramelteon. The animals did not press the lever associated with midazolam, their lack of response indicating that they felt different after receiving ramelteon than they did after receiving midazolam.