Ambien: Worth the few extra zzz's?

Ambien is like the new warm milk of insomnia cures: 43 million scripts for the drug (and generic and related versions) were written in 2012 alone. But new info is revealing serious concerns, and the drug seems to affect women differently than men. Read this before you pop.

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There's the zombie effect. Ambien and its generic, zolpidem, work by latching onto a brain molecule, the GABA-A receptor, that dampens brain activity, making you sleepy. The effect is so strong in some people that when you rouse in the night (say, to roll over), the prefrontal cortex, which controls planning and self-restraint, keeps snoozing. So your body's active but your conscious brain isn't, and behaviors like sleepwalking are more common. Some Ambien-related mishaps border on funny, like the woman who unknowingly ate an entire 9" x 11" pan of tuna casserole. But some people have reported doing scary stuff while on zolpidem, like sleep driving and waking up behind the wheel of a crashed car. Not that they necessarily remember—Ambien can also cause amnesia: When it turns on the GABA-A receptor, the brain may have trouble forming new memories.

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The drug may also be deadly. In a study comparing 10,000 users of sleeping pills like zolpidem to nonusers, pill takers were up to 35 percent more likely to develop some type of cancer, including lymphoma and lung cancer, and they were 4.56 times more likely to die of any cause. Though the reasons are still unclear, "the risk of death was substantial even in people taking just 18 pills a year—but it increased the more they took," said study author Dr. Daniel Kripke, of the Scripps Clinic Viterbi Family Sleep Center in San Diego. (Sanofi, Ambien's maker, says this kind of analysis suggests association, not cause, and that the drug is safe when used as directed.)

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And it may hit us harder. In a study involving both sexes taking the same dose of zolpidem, women had much more of the drug in their bloodstream, and it stayed there longer. No one knows exactly why. But one study found that the morning after taking zolpidem, some women were so groggy, their driving was technically worse than if they had been legally drunk—one reason the FDA halved the recommended dosage for women.

The bottom line. Most people tolerate the drug with no behavioral mishaps, says the FDA. But there's no way to know if you'll be the exception, and the risk of potential hazards may remain. The craziest thing: For all their drawbacks, drugs like Ambien help people fall asleep on average just 13 to 17 minutes faster and increase total sleep time by only about 11 to 32 minutes a night. Warm milk, anyone?

This article originally appeared on Self.com.