Studies of sleeping pills show that men and women need different doses to get the same result. For example, the Food and Drug Administration (F.D.A.) recommends that women take 1.75 milligrams of the sleeping drug Intermezzo versus 3.5 milligrams for men.
Research is showing that men and women metabolize drugs, including aspirin, in different ways. A scientist said, “There are a lot of sex differences for a lot of drugs, some of which are well-known and some that are not.”
One reason we now are learning more is that women used to be left out of trials of new drugs. In 1993, the ban on testing women of childbearing age was lifted. Studies now show that women also react differently to alcohol, tobacco and cocaine.
It is not just because of their size. Women have a higher percentage of body fat, hormonal changes and a menstrual cycle. These differences affect how the body handles drugs.
There are also sex differences in liver and kidney function and certain gastric enzymes. Oral contraceptive, menopause and later hormone treatment also produce different drug effects.
Researchers say more women are needed in clinical trials. They note that women are not used as much as they should be in heart, kidney and even cancer trials.