NIH: New Drugs Must Be Tested on Both Sexes

The National Institutes of Health (NIH) want to see changes made in the way medical researchers in the United States conduct scientific studies. At the moment, the vast majority of tests are conducted on males, from the cellular stage to the all-inclusive human. When the tests are conducted on humans, the study population is overwhelmingly men. This practice, says the NIH, doesn’t provide enough information to determine if a medicine, procedure, or device is safe for women, too.

Pill bottlesWomen are cautioned to avoid using any unnecessary prescription or over-the-counter (OTC) medications during pregnancy and lactation. They’re advised to discuss any herbal remedies and nutritional supplements with their maternal-fetal specialist before taking them. The warnings have a lot to do with the extreme vulnerability of a developing fetus and newborn baby but it’s also because so few drugs, including OTC drugs and supplements, have been tested on women, much less on pregnant and lactating women.

As medical science gains a deeper understanding of human biology, it becomes increasingly clear that sex is evident in every cell of the body. The hormones, genetics, and general physiology of a woman is different from that of a man all the way down to the cellular level. Some medicines that work for men don’t work so effectively in women. Some symptoms of illness differ from male to female. Examples of sex differences include:

  • Women are more likely to develop multiple sclerosis (MS) than men are but the disease usually affects men more severely.
  • Female lab rats are more likely to abuse alcohol and cocaine when anxious or under extreme stress than male rats.
  • Human women are more likely to feel temporary relief from withdrawal cravings for alcohol, cocaine, opioids, and nicotine when taking guanfacine, a drug commonly prescribed for hypertension, attention-deficit hyperactivity disorder, and anxiety but it doesn’t relieve withdrawal symptoms as effectively for men.
  • Typical heart attack symptoms vary widely between men and women; women often don’t realize they’re having a heart attack and medical personnel often misdiagnose them.

Testing of a new drug, procedure, or medical device is a multi-phased process. It first begins with just tissue samples and, if results produced the desired outcome, the research is advanced to include animal tests. Male animals are used more often than females due to the simpler hormone system of male mammals and because female animals cost more. It’s at the tissue- and animal-testing phases that the NIH wants to see more study on female cells, tissues, and animals.

Once a clinical trial advances the to the human stage, men are used more often than women, especially women of reproductive age, due to concerns of ethics and reproductive health. As the gender divide is becoming more apparent on even the microscopic level, it is becoming increasingly evident that testing of female tissue is needed for optimum safety and effectiveness for all.


Source: Clayton, Janine A., and Francis S. Collins. “Policy: NIH to balance sex in cell and animal studies.” Nature. Nature Publishing Group / Macmillan Publishers Limited. May 14, 2014. Web. Jun 15, 2014.

Keyword Tags: