SLEEPING PILLS: THE NEXT GENERATION

For a decade, Ambien has been the answer to many an insomniac's prayer--but a new generation of sleep aids that are less addictive and less likely to cause a morning-after "hangover" are about to hit the market. In April, Sepracor launched Lunesta, the first sleep drug approved with no time limit for use. (Drugs like Ambien are recommended for 10 days or less because they haven't been tested for long-term use.) Late Friday, the Food and Drug Administration approved a second long-term sleep aid called Rozerem, which remained effective for up to a year in trials with no detrimental effects.

Made by Japan's Takeda Pharmaceutical, Rozerem works differently from Sanofi-Aventis's Ambien, King Pharmaceuticals' Sonata, Lunesta and other "hypnotic" sleep aids that have a sedating effect that lasts about four to eight hours. Rozerem, which may be available by September, binds to melatonin receptors that regulate sleep-wake cycles, so it may be taken in the middle of the night with less chance of next-day grogginess. It's also the first prescription sleep aid to show no risk of addiction (a potential side effect of sedating drugs). Pfizer and Neurocrine Biosciences also have a long-term drug, indoplin, awaiting FDA approval that works like Lunesta, but without lingering drowsiness. And Merck's drug, gaboxadol, may be out by 2008--the first of a new class to target the brain's GABA-A receptors, which are believed to help regulate sleep.

About 60 million Americans experience bouts of insomnia annually, according to the National Institutes of Health. Increasingly, they're turning to prescription pills. More than 35 million prescriptions were written for sleep aids in the United States last year, amounting to more than $2.1 billion. Of course, drugs aren't the only insomnia treatment--cognitive behavior therapy, for example, has gained popularity. But drugmakers are betting millions that for many Americans, they may be the preferred choice.