A closer look
Taking the exact same dose of a drug can yield wildly different results depending on a calendar. Fluctuating estrogen and progesterone levels during the menstrual cycle dramatically alter how liver enzymes metabolize medications like the sleep aid Zolpidem or various antidepressants. Because clinical trials historically treated women as smaller versions of men, the medical world is only just realizing that a perfectly safe dosage on day five of a cycle might leave a patient entirely overmedicated on day twenty.
