A recent study found that hormones used in oral contraceptive pills or in hormone replacement therapy (HRT) can affect the speed at which a woman’s body metabolizes other drugs.
Presented recently at the American Society of Clinical Pharmacology, the Northwestern University study tested how HRT and oral contraceptives affected the metabolism of three different drugs — the heart drug verapamil, the antibiotic erythromycin, and a cough suppressant called dextromethorphan. In each test, a control group of women who did not take oral contraceptives or HRT were monitored along with those who did.
Results found that women taking oral contraceptives metabolizes verapamil 46% faster than women in the control group. Oral contraceptive use also appeared to speed the metabolism of erythromycin, also the increase was not statistically significant. The metabolism of dextromethorphan was unaffected by oral contraceptive use.
Women undergoing HRT did not metabolize the three drugs any differently than women who did not take hormones.