Sex Bias in Your Medicine Cabinet?
by Sophia Cariati

(Washington DC, 6/24/01): The safety and effectiveness of a number of widely used drugs including antihistamines, antibiotics, and pain relievers varies depending upon the sex of the user, according to results of an ever-increasing number of studies. "While still a fairly new concept, it is becoming increasingly clear that physicians and patients should consider sex when choosing a drug therapy," said Phyllis Greenberger, MSW, president and CEO of the Society for Women's Health Research in Washington, DC.

In fact, at least four of ten drugs recently removed from the market pose greater health risks to women than to men, according to a 2001 U.S. governmental report. The majority of these medications put women at an increased risk of potentially fatal irregular heartbeats or arrhythmias. And other drugs, still on the market, have also been shown to increase the risk of arrhythmia in women. Studies have demonstrated that some antibiotics, heart medications and psychiatric drugs are associated with an increased incidence of heartbeat irregularities among women.

For other medications, the effectiveness, not safety, changes depending upon whether a man or woman is taking the drug. For example, University of California at San Francisco researchers led by Jon Levine, MD found morphine-like painkillers called kappa opiods provide more powerful and long-lasting relief to women than men. In fact, at some doses kappa-opiods can actually make the pain worse for men and afford excellent pain relief to women, according to Dr. Levine.

General anesthesia, drugs that render a person unconscious during surgery, also can behave differently in men and women. At least two studies suggest women may be less responsive to anesthesia than men. The research shows that women wake up 3 to 4 minutes faster than men after taking the same dose of medication per pound of body weight and tend to suffer more side effects.

Why do men and women respond differently?

Exactly why these drugs affect men and women differently remains unclear. And in fact, the answer may turn out to be different for every class of medication. Nonetheless, research points to a number of possible mechanisms for these sex-based differences.

The varying rate at which men and women metabolize drugs may be involved. Studies show that some liver enzymes involved in processing pharmaceuticals are more active in women than in men. In addition, evidence suggests that the amount of drug that actually gets into the cells of the body may vary among the sexes partly due to differences in drug- transport mechanisms.

Anatomy also affects the way drugs are processed. On average, women have a lower body weight, smaller organ size, reduced blood flow and a higher proportion of fat compared with men. Overall differences in hormonal activity between the sexes affect the way drugs are processed, absorbed and cleared by the body as well.

In addition, organs seem to function differently depending upon whether they are inside a male or female body. Evidence suggests that "female" kidneys are slower to act than "male" kidneys. In addition, liver functioning, which can influence the incidence of adverse events, may vary among men and women. What's more, the rate at which drugs pass through the gastrointestinal system, which affects how much is absorbed into the bloodstream, seems to differ among the sexes.

Educate yourself before taking a new drug

According to Sherry Marts, PhD, scientific director of the Society for Women's Health Research, "Despite mounting evidence showing that men and women respond differently to the same drug, most physicians and their patients are still not aware that sex matters when prescribing medications."

Why the lack of awareness? One of the reasons is that the Food and Drug Administration and the pharmaceutical industry, groups responsible for drug labeling, only recently began to analyze safety data by gender. In fact, reporting of gender-based data analysis in medical journals, while increasing, is still not routine practice, according to Dr. Marts. This shortcoming of the system keeps gender-specific risks as well as benefits buried beneath heaps of data.

So what can you do to protect yourself from potentially harmful or ineffective drugs? Women must demand that their physicians and pharmacists fully inform them about the pharmaceuticals they are prescribed. Before leaving the doctor's office or pharmacy, make sure you have answers to the following questions:

• Are there known sex or gender differences in how the drug works?
• What are the benefits of this drug?
• What are the common, rare, and serious side effects?
• Are there any safer alternatives to this drug?
• Can the prescription interfere with other medications I am taking, especially birth control pills or hormone replacement therapy?
• Does the drug have any serious interactions with other drugs?

The Society for Women's Health Research is the nation's only not-for-profit organization whose sole mission is to improve the health of women through research. Founded in 1990, the Society brought to national attention the need for the appropriate inclusion of women in major medical research studies and the resulting need for more information about conditions affecting women. The Society advocates increased funding for research on women's health, encourages the study of sex differences that may affect the prevention, diagnosis and treatment of disease, and promotes the inclusion of women in medical research studies. Dr. Donnica Moore has been a member of the Society since 1990 and is a past member of its Board of Directors.

For more information on clinical research, click here.

Created: 6/24/2002  -  Sophia Cariati