Women are almost twice as likely as men to suffer from overmedication and adverse side effects of drugs because they are not accurately represented in many drug dose trials, according to new research. This disparity in medical trials could lead to severe consequences for cis women, trans men, and non-binary or agender people assigned female at birth.
Reported in the journal Biology of Sex Differences, scientists at UC Berkeley and the University of Chicago sifted through over 5,000 scientific studies looking at sex-based differences in drug safety, drug dose, adverse drug reactions, and pharmacokinetics (the field of study that looks at how drugs are processed by a living organism). Out of the 86 drugs evaluated, they found that 76 were processed differently by males and females. They added that this was not explained by body weight alone, but are most likely linked to pharmacokinetic differences between the sexes.
As a result of these differences, in over 90 percent of cases, women and people assigned female at birth experienced worse side effects, such as nausea, headache, depression, cognitive deficits, seizures, hallucinations, agitation, and cardiac anomalies. The researchers also found that women experience adverse drug reactions nearly twice as often as men.
“When it comes to prescribing drugs, a one-size-fits-all approach, based on male-dominated clinical trials, is not working, and women are getting the short end of the stick,” Irving Zucker, lead study author and a professor emeritus of psychology and of integrative biology at UC Berkeley, said in a statement.
A well-known example of this problem can found in Zolpidem, the popular sleep medication sold under the brand name Ambien. In 2018, the US Food and Drug Administration (FDA) warned that taking a nighttime dose of Ambien can cause some people to feel groggy and unalert the next morning, potentially upping the risk of traffic accidents and injuries in the workplace. Since the drug lurks for longer in the bloodstream of women, it’s thought they would be at an even higher risk, and it's only recently the recommended dosage has been halved for women.
Somewhat remarkably, “women of child-bearing age” were often excluded from drug trials until the early 1990s because it was considered too risky to expose potentially pregnant women to drugs that were still being tested. This became an especially prominent concern following Thalidomide scandal in the 1950s and 1960s, in which a morning sickness drug caused thousands of babies to be born with limb defects. The number of women in drug trials has increased in recent decades, but the researchers argue that it still fails to analyze the data for sex differences.
This problem of sex-bias is unlikely to just be found in drug trials, say the researchers, and is almost certainly found in a broad range of scientific fields.
“Neglect of females is widespread, even in cell and animal studies where the subjects have been predominantly male,” added Zucker.
In light of their findings, the research team is now talking to experts in the medical profession and pharmaceutical industry advocating for dosage reductions for women for a wide range of drugs.
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