desogestrel

Desogestrel is a synthetic progestin used in hormonal contraception. It is a prodrug that is rapidly converted in the body to etonogestrel, the active metabolite responsible for most of its hormonal effects. Desogestrel is available in combined oral contraceptives with an estrogen (typically ethinylestradiol) and in a progestin-only pill formulation in some markets.

Mechanism of action is similar to other progestins. By suppressing the hypothalamic-pituitary-ovarian axis, desogestrel reduces or stops ovulation in many cycles. It also thickens cervical mucus and causes changes in the endometrium that reduce the likelihood of fertilization and implantation. The exact pattern of ovulation suppression can vary between individuals and regimens.

Medical uses and forms. Desogestrel is primarily used for contraception. In combined oral contraceptives it is paired with an estrogen to provide cycle control and pregnancy prevention. In progestin-only regimens, desogestrel provides contraception while avoiding estrogen exposure, which is important for certain individuals. It is not intended for treatment of other conditions outside of contraception in standard practice.

Side effects and safety. Common adverse effects include irregular vaginal bleeding or spotting, headaches, breast tenderness, nausea, and changes in weight or mood. Serious risks associated with progestin-containing contraceptives include an increased risk of venous thromboembolism and cardiovascular events, particularly in appropriate age groups when combined with estrogen. Contraindications include pregnancy, history of thromboembolic disease, liver disease, certain cancers, undiagnosed vaginal bleeding, and known hypersensitivity to components. Interactions with hepatic enzyme inducers can reduce contraceptive effectiveness.

Pharmacokinetics. Desogestrel is absorbed orally and rapidly converted to etonogestrel. Metabolism is largely hepatic, with excretion via urine and feces. Drug interactions mainly involve enzymes such as CYP3A4.