Abiraterone acetate is a prodrug of abiraterone, a potent, selective, and irreversible inhibitor of cytochrome P450 17A1 (CYP17A1), an enzyme critical for androgen biosynthesis in the testes, adrenal glands, and prostate tumor tissue. It is a cornerstone of treatment for metastatic castration-resistant prostate cancer (mCRPC) and metastatic castration-sensitive prostate cancer (mCSPC) in the Indian context, used in combination with prednisone/prednisolone and androgen deprivation therapy (ADT).
Adult: 1000 mg (four 250 mg tablets) orally once daily, in combination with prednisone 5 mg orally twice daily or prednisolone 5 mg orally twice daily.
Note: Swallow tablets whole with water. Do not crush or chew. Must be taken on an EMPTY STOMACH. No food should be consumed for at least 2 hours before and at least 1 hour after taking abiraterone acetate. Dosing should be consistent with respect to food (always fasting).
Abiraterone acetate is a prodrug converted to abiraterone, which irreversibly inhibits the enzyme cytochrome P450 17A1 (CYP17A1). This enzyme is expressed in testicular, adrenal, and prostatic tumor tissues and has two key activities: 17α-hydroxylase and C17,20-lyase. Inhibition of C17,20-lyase is particularly crucial as it blocks the conversion of pregnenolone and progesterone precursors into dehydroepiandrosterone (DHEA) and androstenedione, the immediate precursors to testosterone and dihydrotestosterone (DHT). This results in a profound suppression of androgen synthesis from all sources.
Pregnancy: Category X. Abiraterone can cause fetal harm when administered to a pregnant woman. It is not indicated for use in women. Male patients with female partners of reproductive potential must use effective contraception during and for 3 weeks after treatment.
Driving: Fatigue, dizziness, and visual disturbances have been reported. Patients should be cautioned about operating machinery or driving if they experience these effects.
| Strong CYP3A4 Inducers (e.g., Rifampicin, Phenytoin, Carbamazepine, St. John's Wort) | Decrease abiraterone exposure significantly, potentially reducing efficacy. Coadministration is contraindicated. | Major |
| Strong CYP3A4 Inhibitors (e.g., Ketoconazole, Itraconazole, Clarithromycin, Ritonavir) | Increase abiraterone exposure. If coadministration is necessary, reduce abiraterone dose to 250 mg once daily with close monitoring. | Major |
| Drugs that lower serum potassium (e.g., Diuretics, Amphotericin B) | Increased risk of severe hypokalemia. Monitor potassium levels closely. | Moderate |
| Corticosteroids (Prednisone/Prednisolone) | Concomitant use is required. Be aware of additive immunosuppressive and hyperglycemic effects. | Moderate (Therapeutic) |