Pharmacokinetic approach of clinically important drug interactions of hormonal contraceptives – a review

Hormonal contraceptives contain an Estrogen and/or a Progestin, which are the substrates of the CYP3A4 enzyme and the drugs inducing the CYP3A4 enzyme can decrease the plasma concentrations and thereby therapeutic efficacy of Hormonal contraceptives resulting in unintended pregnancy. Moreover, the hormonal contraceptives associated risk of thrombotic events are further exacerbated by the simultaneous administration of drugs like Tranexamic acid and tobacco smoke. Therefore, while prescribing hormonal contraception and other drugs to women, drug interactions should always be considered because there could be a possible contraceptive failure or other adverse drug effects. This article provides a summary of guidance to healthcare professionals such as prescribers and pharmacists on pharmacokinetic based interactions between hormonal contraception and other drugs.