Chlormadinone

Chlormadinone is a progestogen. The following information refers to chlormadinone acetate only, as chlormadinone is only used in its acetylated form. Chlormadinone acetate (CMA) is a progestin and antiandrogen medication used in birth control pills for pregnancy prevention, as a component of menopausal hormone therapy, in the treatment of gynecologic conditions, and in the treatment of androgen-dependent conditions such as enlarged prostate and prostate cancer in men and acne and hirsutism in women. It is usually taken by mouth, but can also be administered by injection into a muscle.

Pharmacodynamics

Chlormadinone acetate has progestagenic activity, antigonadotropic effects, antiandrogenic activity, and weak glucocorticoid activity. Thus, the drug behaves similarly to the hormones progesterone and cortisol and inhibits the activity of sex hormones.

Pharmacokinetics

The oral bioavailability of CMA is 100%, which is due to low first-pass metabolism. The drug is highly lipophilic and is absorbed and accumulated in fat and some female reproductive tissues. Plasma protein binding of CMA is 96.6 to 99.4%, with about 1 to 3% free. It is primarily bound to albumin. CMA is extensively metabolized in the liver by reduction, hydroxylation, deacetylation, and conjugation. The elimination half-life of CMA is reported to be 25 to 34 hours after a single dose and 34 to 39 hours after multiple doses. The drug is excreted 33 to 45% in urine and 24 to 41% in feces and bile.

Side effects

Side effects of combining an estrogen and CMA include menstrual irregularities, headaches, nausea, breast tenderness, vaginal discharge, and others. At high doses, CMA can cause sexual dysfunction, emasculation, adrenal insufficiency, and changes in carbohydrate metabolism, among other adverse effects.