In females, the most common adverse effects are acne, changes in menstrual flow, drowsiness, and can cause birth defects if taken by pregnant women. Other common side effects include breast tenderness, increased facial hair, decreased scalp hair, difficulty falling or remaining asleep, stomach.
In females, the most common adverse effects are acne, changes in menstrual flow, drowsiness, and can cause birth defects if taken by pregnant women. Other common side effects include breast tenderness, increased facial hair, decreased scalp hair, difficulty falling or remaining asleep, stomach pain, and weight loss or gain.
The Women's Health Initiative investigated the use of medroxyprogesterone 17-acetate and conjugated equine estrogens compared to placebo. The study was prematurely terminated when previously-unexpected risks were discovered, specifically the finding that though the all-cause mortality was not affected by the hormone therapy, the benefits of the hormone replacement therapy (reduced risk of hip fracture, colorectal and endometrial cancer and all other causes of death) were offset by increased risk of coronary heart disease, breast cancer, strokes and pulmonary embolism.
At high doses for the treatment of breast cancer, MPA can cause weight gain, worsen diabetes mellitus and edema (particularly of the face). Adverse effects peak at five weeks, and are reduced with lower doses. Less frequent effects may include thrombosis (though it is not clear if this is truly a risk, it can not be ruled out), painful urination, anxiety, headache, nausea and vomiting. When used to treat benign prostatic hyperplasia, more frequent complaints include reduced libido, impotence, reduced ejaculate volume, and within three days, chemical castration. MPA may cause reduced bone density though this appears to be reversible to a normal level even after years of use. At extremely high doses (used to treat cancer, not for contraception) MPA may cause adrenal suppression and interfere with carbohydrate metabolism but does not cause diabetes.
Fetuses exposed to progesterones have demonstrated higher rates of genital abnormalities, low birth weight, and increased ectopic pregnancy particularly when MPA is used as an injected form of long-term birth control. When used as a form of injected birth control, MPA can reduce fertility for as long as 10 months, taking longer for overweight or obese women. When combined with conjugated equine estrogens (Premarin), MPA has been associated with an increased risk of breast cancer, dementia and thrombus in the eye. In combination with estrogens in general, MPA may increase the risk of cardiovascular disease, with a stronger association when used by post-menopausal women also taking CEE. MPA is not recommended for use prior to menarche or before or during recovery from surgery. It was because of these unexpected interactions that the Women's Health Initiative study was ended early due the extra risks of hormone replacement therapy, producing a dramatic decrease in both new and renewal prescriptions for hormone therapy.
Adapted from the Wikipedia article Medroxyprogesterone 17-acetate, under the G. N. U. Free Documentation License. Please also see http://en.wikipedia.org/wiki