ATC Code G03DB06
Formula C21H27ClO3
Molar Mass (g·mol−1) 362,89
Physical State solid
CAS Number 1961-77-9
PUB Number 5284533
Drugbank ID DB13528
Solubility practically insoluble in water


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.



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.


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.

Markus Falkenstätter

Markus Falkenstätter

Markus Falkenstätter ist Autor zu pharmazeutischen Themen in der Medizin-Redaktion von Medikamio. Er befindet sich im letzten Semester seines Pharmaziestudiums an der Universität Wien und liebt das wissenschaftliche Arbeiten im Bereich der Naturwissenschaften.

Mag. pharm Stefanie Lehenauer

Mag. pharm Stefanie Lehenauer

Stefanie Lehenauer ist seit 2020 freie Autorin bei Medikamio und studierte Pharmazie an der Universität Wien. Sie arbeitet als Apothekerin in Wien und ihre Leidenschaft sind pflanzliche Arzneimittel und deren Wirkung.

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