Drugs That Inhibit Or Induce CYP3A4 Enzymes: Based on in vitro data, Zyterone is a substrate of CYP3A4. In a dedicated drug interaction trial, co-administration of Rifampin, a strong CYP3A4 inducer, decreased exposure of Zyterone by 55%. Avoid concomitant strong CYP3A4 inducers during Zyterone treatment. If a strong CYP3A4 inducer must be co-administered, increase the Zyterone dosing frequency. In a dedicated drug interaction trial, co-administration of ketoconazole, a strong inhibitor of CYP3A4, had no clinically meaningful effect on the pharmacokinetics of Zyterone.

Effects Of Zyterone On Drug Metabolizing Enzymes: Zyterone is an inhibitor of the hepatic drug-metabolizing enzymes CYP2D6 and CYP2C8. In a CYP2D6 drug-drug interaction trial, the Cmax and AUC of Dextromethorphan (CYP2D6 substrate) were increased 2.8- and 2.9-fold, respectively, when Dextromethorphan was given with Zyterone 1,000 mg daily and Prednisone 5 mg twice daily. Avoid co-administration of Zyterone with substrates of CYP2D6 with a narrow therapeutic index (e.g., Thioridazine). If alternative treatments cannot be used, consider a dose reduction of the concomitant CYP2D6 substrate drug. In a CYP2C8 drug-drug interaction trial in healthy subjects, the AUC of Pioglitazone (CYP2C8 substrate) was increased by 46% when Pioglitazone was given together with a single dose of 1,000 mg Zyterone. Therefore, patients should be monitored closely for signs of toxicity related to a CYP2C8 substrate with a narrow therapeutic index if used concomitantly with Zyterone.

Recommended Dose For Metastatic CRPC: The recommended dose of Abiraterone Acetate is 1,000 mg (two 500 mg tablets or four 250 mg tablets) orally once daily with Prednisone 5 mg orally twice daily.

Recommended Dose For Metastatic High-Risk CSPC: The recommended dose of Abiraterone Acetate is 1,000 mg (two 500 mg tablets or four 250 mg tablets) orally once daily with Prednisone 5 mg administered orally once daily.

Patients receiving Abiraterone Acetate should also receive a gonadotropin-releasing hormone (GnRH) analog concurrently or should have had bilateral orchiectomy. Abiraterone Acetate must be taken on an empty stomach, at least one hour before or at least two hours atier a meal. The tablets should be swallowed whole with water. Do not crush or chew tablets.

Hypersensitivity to the Abiraterone acetate or to any of the excipients of Abiraterone.

The most common adverse reactions are fatigue, arthalgia, hypertension, nausea, edema, hypokalemia, hot flush, diarrhea, vomiting, upper respiratory infection, cough, and headache.

The safety and efficacy of Abiraterone have not been established in females. Based on findings from animal studies and the mechanism of action, Abiraterone can cause fetal harm and potential loss of pregnancy. There are no human data on the use of Abiraterone in pregnant women. The safety and efficacy of Abiraterone have not been established in females. There is no information available on the presence of abiraterone acetate in human milk, or on the effects on the breastfed child or milk production.

Zyterone may cause hypertension, hypokalemia, and fluid retention as a consequence of increased mineralocorticoid levels resulting from CYP17 inhibition. Patients should be monitored for hypertension, hypokalemia, and fluid retention at least once a month. Hypertension and hypokalemia should be controlled and corrected before and during treatment with Zyterone. Patients should be monitored for symptoms and signs of adrenocortical insufficiency. Serum transaminases (ALT and AST) and bilirubin levels should be measured prior to starting treatment with Zyterone, every two weeks for the first three months of treatment and monthly thereatier.

There is no specific antidote. In the event of an overdose, Zyterone should be stopped, general supportive measures are undertaken, including monitoring for arrhythmias and cardiac failure and assess liver function.

Do not store above 25°C. Protect from light. Keep out of the reach of children.