Desogestrel

Desogestrel is a progestin medication used in birth control pills for women. It is also used to treat menopausal symptoms in women. The drug is available and is used alone or in combination with an estrogen. It is taken by mouth.

Pharmacodynamics

Oral contraceptives containing desogestrel suppress gonadotropins, thereby inhibiting ovulation. Specifically, desogestrel binds to progesterone and androgen receptors and slows the release of gonadotropin-releasing hormone (GnRH) from the hypothalamus. This process results in suppression of the normal physiological rise in luteinizing hormone (LH) that precedes ovulation. It inhibits follicular rupture and the release of viable eggs from the ovaries. Desogestrel has been shown to be more effective when administered prior to ovulation.

Pharmacokinetics

Oral absorption is rapid and maximum plasma concentration is reached after about 2 hours. Bioavailability is approximately 60-80%. Plasma protein binding is approximately 96-98%. Metabolism occurs in the liver where desogestrel is converted to its active metabolite etonogestrel. Excretion takes place mainly in the urine.

Side effects

Common side effects of Desogestrel may include menstrual irregularities, amenorrhea, headache, nausea, breast tenderness, and mood changes (e.g., depression), as well as weight gain, acne, and hirsutism.

Desogestrel may also cause changes in total, LDL, and HDL cholesterol levels. Rare side effects of desogestrel include vaginal infections, contact lens intolerance, vomiting, hair loss, dysmenorrhea, ovarian cysts, and fatigue, while rare side effects include rash, urticaria, and erythema nodosum. Breast discharge, ectopic pregnancy, and worsening of angioedema may also occur with desogestrel.

Serious adverse reactions to combined oral contraceptives containing desogestrel may include venous thromboembolism, arterial thromboembolism, hormone-dependent tumors (e.g., liver tumors, breast cancer), and melasma.

Toxicological data

LD50 (rat, oral): >2000 mg/kg