It's Not Just Mars or Venus Anymore


What are the differences between men and women? This week, we're looking at how men and women respond differently to prescription drugs and yet they're given the same doses. Take the recent case involving Lunesta.

The FDA required that the sleep aid Lunesta's starting dose be reduced from two to one milligram because women stay drowsy far longer than men. It posed a safety risk for women driving and working. This one size fits all approach can't be practical when men and women are obviously physiologically different.

So why are drugs developed this way? From basic studies in biomedical science where cell lines are used to experimental animals such as lab mice, they're mostly male. The majority of clinical trials involving humans enroll men.

How did this situation occur? For many years, women weren't included in trials because of concerns they were pregnant or would become pregnant. Their hormones alter metabolism or interact with drugs.

Their gastrointestinal absorption rate is different which alters drug levels in the blood. We've also learned the female kidney's glomerular filtration is slower at clearing drugs compared to men. Aspirin is less effective at lowering subsequent heart attacks in women. Beta blockers also work differently. All this made researchers avoid women to lessen the complexity of their drug trials.

To change that, studies are now required to represent both genders. This may

More Information

Sex Based Differences in Drug Activity
Journal article that reviews the many examples of differential drug action among the genders.
American Family Physician 80: 154-1258, 2009.

Is Medical Treatment Too Gender Neutral?
Short article that reports the views of 10 physicians.

Drugs can affect men and women differently
CBS News — "Differences between sexes are more pervasive than previously thought; scientists call for a re-examination of medical research, including drug dosages, based on sex"