Men and women often respond in very different ways to many medications. This may explain why many women experience more than their fair share of adverse reactions, certainly more than men tend to.
The Food and Drug Administration has done an evaluation of the new drug Intermezzo, and concluded that women should be given half the dosage recommended for men -- 3.5 milligrams for men and 1.75 milligrams for women.
Intermezzo's active ingredient is zolpidem, which is used in other sleeping aids. The FDA has ordered the makers of many sleeping pills including zolpiderm to cut dosages for women in half.
According to research, 15 percent of women taking these sleeping pills are still affected by the medication to the point that driving, for instance, can be dangerous. Behind the wheel, these delayed reactions can lead to serious car accidents.
Dr. Michel Cramer Bornemann of Hennipen County Medical Center's sleep disorders clinic said that women are having delayed reaction times as they metabolize the sleeping pills.
There were 40 million prescriptions in the United States for sleeping pills with zolpiderm in 2011.
Most data concerning medications is based on drug trials that only involved testing of men. Women were not being included in new drug trials until 1993.
This was in part to protect women of childbearing age. Unfortunately, this has left researchers with little information as to how women are actually affected by the use of many drugs.
Many drugs like the antihistamine Seldane and Propulsid for gastrointestinal issues, as well as many antibiotics, anti-malarial drugs, antipsychotics and drugs to lower cholesterol, can cause heart arrhythmia in women that can be fatal.
On the other hand, said the Society for Women's Health Research, some drugs like Verapamil for high blood pressure and the antibiotic erythromycin, work better for women than for men. Women come out of anesthesia faster and with fewer side effects than men.
Women are generally smaller than men, and their metabolism of drugs happens differently due to their higher body fat and monthly hormonal fluctuations.
Hormonal medications like oral contraception and treatments for menopause that women may use also have effects that are difficult to predict and work around.
Men and women also differ in kidney function and liver metabolism. There are difference as to some gastric enzymes as well.
Some researchers are convinced that it is essential to have more information concerning sex differences when a drug is developed.
The director for the Office of Research on Women’s Health at the National Institutes of Health, Dr. Janine Clayton, said that the findings concerning sex differences in regards to medications is "just the tip of the iceberg".