Description Cyproterone (SYE-proe-te-rone) is used to treat cancer of the prostate gland. The prostate gland is present only in males; therefore, females do not get prostate cancer. This medicine blocks the effect of the male hormone testosterone in the body. This decreases the amount of testosterone produced in the body and is one way of treating this type of cancer. This medicine is available only with your doctor's prescription, in the following dosage forms: Oral Tablets (Canada) Parenteral Injection (Canada) Before Using This Medicine In deciding to use a medicine, the risks of using the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For cyproterone, the following should be considered: Allergies-Tell your doctor if you have ever had any unusual or allergic reaction to cyproterone. Also tell your doctor and pharmacist if you are allergic to any other substances, such as foods, preservatives, or dyes. Pregnancy-Studies on effects in pregnancy have not been done in either humans or animals. Breast-feeding- It is not known whether cyproterone passes into the breast milk. However, this medicine has not been reported to cause problems in nursing babies. Children-Studies on this medicine have been done only in adult patients, and there is no specific information comparing use of cyproterone in children with use in other age groups. Older adults-Many medicines have not been studied specifically in older people. Therefore, it may not be known whether they work exactly the same way they do in younger adults or if they cause different side effects or problems in older people. There is no specific information comparing use of cyproterone in the elderly with use in other age groups. Other medicines-Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking cyproterone, it is especially important that your health care professional know if you are receiving any of the following: Ethinyl estradiol (eg, Estinyl)-Concurrent use with cyproterone may cause blood clotting problems Other medical problems-The presence of other medical problems may affect the use of cyproterone. Make sure you tell your doctor if you have any other medical problems, especially: Blood clots (or history of) or Circulation disease (or history of) or Stroke (or history of)-If these conditions already are already present, cyproterone may have a greater chance of causing blood clot problems Cardiac disease-May make the condition worse Depressive tendencies-May cause depression to occur Type 2 diabetes mellitus-May cause a loss of control of diabetes by increasing blood and urine sugar Liver disease-Effects of cyproterone may be increased because of its slower removal from the body Proper Use of This Medicine At first, cyproterone often causes loss of strength and energy or tiredness. However, these effects are lessened after about the third month of treatment and it is very important that you continue to receive this medication. This medication should not be discontinued even if improvement of the disease occurs. Dosing-The dose of cyproterone will be different for different patients. The dose that is used may depend on a number of things, including what the medicine is being used for, the patient's body size, and whether or not other medicines are also being taken. If you are taking or receiving cyproterone at home, follow your doctor's orders or the directions on the label. If you have any questions about the proper dose of cyproterone, ask your doctor. For oral dosage form: For treating prostate cancer: Adults-100 to 200 milligrams (mg) (2 to 4 tablets) a day divided into 2 to 3 doses and taken after meals. For injection dosage form: For treating prostate cancer: Adult-300 mg (3 mL) injected into a muscle once a week. Missed dose-If you miss a dose of this medicine, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not double doses. Storage-To store this medicine: Keep out of the reach of children. Do not store in the bathroom, near the kitchen sink, or in other damp places. Heat or moisture may cause the medicine to break down. Keep the medicine from freezing. Do not keep outdated medicine or medicine no longer needed. Ask your health care professional how you should dispose of any medicine you do not use. Be sure that any discarded medicine is out of the reach of children.