I can’t sleep at night. Should I take a pill?

Now let’s get to sleeping pills, which fall into two categories — short-acting and long-acting — and work on different receptors in the brain.

Short-acting sleeping pills
Short-acting medications include Sonata (zaleplon), Ambien (zolpidem) and Lunesta (eszopiclone). These don’t suppress deep sleep or REM sleep and so have minimal effects on next-day activities and seem not to be addictive.

There are some reports of withdrawal symptoms from Ambien, such as anxiety, tremors, agitation and rebound insomnia. However, if you do a meta-analysis (in other words, look at a bunch of studies), most of these side effects were minimal or absent except for some mild rebound insomnia.

When I prescribe a sleeping pill, I try to assess whether the patient has a problem falling asleep or instead falls asleep easily but awakes before she should and loses the last few hours of her night’s sleep. If she just needs to “catch” those two or three hours, I’ll prescribe the shortest acting pill, Sonata. It peaks in blood levels after one hour and its half life (when half of its active component is out of circulation) is an hour. Next up in duration of effect is Ambien, which peaks in 1.6 hours and has a half life of 2.6 hours. According to studies given to the FDA, the longest acting “short-acting” pill is Lunesta, which peaks in one hour and has a half life of six hours.

All of these medications appear to be effective and relatively safe, with low potential for abuse or tolerance. Unfortunately, I can’t tell you about studies in which one was compared to another because such research doesn’t exist. I can point out, however, that the manufacturer of Lunesta paid for a six-month trial and submitted the results to the FDA, while the manufacturers of other two medications did not.

Short-acting sleeping pills
These are termed  benzodiazapines and include Halcion (triazolam), Restoril (temazepam) and Dalmane (flurazepam). These pills slow central nervous system activity and their effect can last anywhere from several hours to 24 hours. Because they suppress deep and REM sleep, they can cause next-day thinking and remembering deficits. (When the labels say “Don’t operate heavy machinery,” they mean it!)

Only on TODAY.MSNBc.com! Dr. Judith Reichman addresses your questions about women's health. LAST WEEK: Will removing my ovaries prevent cancer? GO TO ALL HEALTH TUESDAY COLUMNS

A final brief note: Over-the-counter sleep aids often contain antihistamines, an arousal chemical in the brain. These medications are popular but can leave you groggy the next day, and they stop working if taken every night. Sometimes rotating an antihistamine and a prescribed pill minimizes side effects.

Dr. Reichman’s Bottom Line: You need a daily break from your hectic life, and that doesn’t mean just closing your eyes; it means getting quality sleep. There is much you can do on your own, without medication, but if you do need extra help, you may want to consider prescription sleep aids. If you understand how and why these medications work, you’ll be better able to discuss their use with your doctor.

Dr. Judith Reichman, the “Today” show's medical contributor on women's health, has practiced obstetrics and gynecology for more than 20 years. You will find many answers to your questions in her latest book, "Slow Your Clock Down: The Complete Guide to a Healthy, Younger You," which is now available in paperback. It is published by William Morrow, a division of HarperCollins.

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