Chemical formula: C₂₂H₂₇ClO₃ Molecular mass: 416.938 g/mol PubChem compound: 9880
Cyproterone interacts in the following cases:
At high therapeutic cyproterone acetate doses of three times 100mg per day, cyproterone acetate may inhibit CYP2C8. Thiazolidinediones (i.e. the anti-diabetics pioglitazone and rosiglitazone) are substrates oF CYP2C8 (increased blood levels of these anti-diabetics may require dose adjustment).
Alcohol may reduce the antiandrogenic effect of cyproterone in hypersexuality. The relevance of this in prostatic carcinoma is not known; however, it would be prudent to inform the patients that the use of alcohol during cyproterone therapy is not advisable.
The effect of cyproterone is of no value in chronic alcoholics.
Clinical interaction studies have not been performed. However, since cyproterone acetate is metabolised by CYP3A4, it is expected that ketoconazole, itraconazole, clotrimazole, ritonavir and other strong inhibitors of CYP3A4 inhibit the metabolism of cyproterone acetate.
The risk of statin-associated myopathy or rhabdomyolysis may be increased when those HMG-CoA inhibitors (statins) which are primarily metabolised by CYP3A4 are co-administered with high cyproterone acetate doses, since they share the same metabolic pathway.
Clinical interaction studies have not been performed. However, since cyproterone acetate is metabolised by CYP3A4, it is expected that inducers of CYP3A4 such as rifampicin, phenytoin and products containing St. John’s Wort may reduce the levels of cyproterone acetate.
Cyproterone may impair carbohydrate metabolism. Parameters of carbohydrate metabolism, fasting blood glucose, and glucose tolerance tests, should be examined carefully in all patients and particularly in all diabetics before and regularly during therapy with cyproterone.
Strict medical supervision is necessary if the patient suffers from diabetes, because the requirement for oral antidiabetics or insulin can change during cyproterone treatment.
Treatment with cyproterone is not indicated for use in women.
Treatment with cyproterone is not indicated for use in women.
Fatigue and lassitude are common – patients should be warned about this and if affected should not drive or operate machinery.
The most frequently observed adverse drug reactions (ADRs) in patients receiving cyproterone are decreased libido, erectile dysfunction and reversible inhibition of spermatogenesis.
The most serious ADRs in patients receiving cyproterone are hepatic toxicity, benign and malignant liver tumours which may lead to intra-abdominal haemorrhage and thromboembolic events.
The following approximate incidences were estimated from published reports of a number of small clinical trials and spontaneous ADR reports: very common: incidence ≥1:10, common: incidence <1:10 but ≥1:100, uncommon: incidence <1:100 but ≥1:1,000, rare: incidence <1:1,000 but ≥1:10,000, very rare: incidence <1:10,000, not known (cannot be estimated from available data).
Rare: Meningioma. The occurrence of meningiomas (single and multiple) has been reported in association with use of cyproterone acetate.
Very rare: Benign and malignant liver tumours which may lead to life-threatening intra abdominal haemorrhage.
Not known: Anaemia during long-term treatment.
Rare: Hypersensitivity reactions may occur.
Not known: Suppression of adrenocorticol function.
Common: Changes in bodyweight during long term treatment (chiefly weight gains in association with fluid retention)
Common: Depressive moods and restlessness (temporary).
Not known: Thromboembolic events, although a causal relationship has not been established.
Common: Dyspnoea.
Common: Direct hepatic toxicity, including jaundice, hepatitis and hepatic failure has been observed in patients treated with cyproterone. At dosages of 100 mg and above, cases with fatal outcome have also been reported. Most reported fatal cases were in men with advanced carcinoma of the prostate. Toxicity is dose related and develops, usually, several months after treatment has begun.
Uncommon: Rash
Not known: Reduction of sebum production leading to dryness of the skin and improvement of existing acne vulgaris has been reported as well as; transient patchy loss and reduced growth of body hair, increased growth of scalp hair, lightening of hair colour and female type of pubic hair growth.
Not known: Osteoporosis (due to long-term androgen deprivation).
Inhibition of spermatogenesis:
Very common: Sperm count and the volume of ejaculate are reduced.
Infertility is usual, and there may be azoospermia after 8 weeks. There is usually slight atrophy of the seminiferous tubules. Follow-up examinations have shown these changes to be reversible, spermatogenesis usually reverting to its previous state about 3-5 months after stopping cyproterone, or in some users, up to 20 months. That spermatogenesis can recover even after very long treatment is not yet known. There is evidence that abnormal sperms which might give rise to malformed embryos are produced during treatment with cyproterone.
Gynaecomastia:
Common: Gynaecomastia (sometimes combined with tenderness to touch of the mamillae) which usually regresses after withdrawal of the preparation.
Rare: Galactorrhoea and tender benign nodules have been reported.
Symptoms mostly subside after discontinuation of treatment or reduction of dosage.
Common: Hot flushes, sweating, fatigue and lassitude.
© All content on this website, including data entry, data processing, decision support tools, "RxReasoner" logo and graphics, is the intellectual property of RxReasoner and is protected by copyright laws. Unauthorized reproduction or distribution of any part of this content without explicit written permission from RxReasoner is strictly prohibited. Any third-party content used on this site is acknowledged and utilized under fair use principles.
