Generic Name and Formulations:
Enzalutamide 40mg; soft gelatin caps.
Astellas Pharma US, Inc.
Indications for XTANDI:
Treatment of metastatic castration-resistant prostate cancer.
Swallow whole. 160mg once daily. Dose modifications: ≥Grade 3 toxicity or intolerable side effect: withhold dosing for 1 week or until symptoms improve to ≤Grade 2, then resume at same or reduced dose (120mg or 80mg), if warranted. Concomitant strong CYP2C8 inhibitors: avoid if possible; if co-administration necessary, reduce enzalutamide dose to 80mg once daily. Concomitant strong CYP3A4 inducers: avoid if possible; if co-administration necessary, increase enzalutamide dose to 240mg once daily. When CYP2C8 inhibitor or CYP3A4 inducer is discontinued, return enzalutamide dose to the dose used prior to initiation of the inhibitor or inducer.
Risk of seizure; permanently discontinue if occurs. Discontinue if posterior reversible encephalopathy syndrome (PRES) develops. Severe renal impairment. Males with female partners of reproductive potential should use effective contraception during treatment and for 3 months after final dose.
Avoid concomitant strong CYP2C8 inhibitors (eg, gemfibrozil) if possible; if co-admin unavoidable, reduce dose (see Adult). Avoid concomitant strong CYP3A4 inducers (eg, carbamazepine, phenobarbital, phenytoin, rifabutin, rifampin, rifapentine, St. John’s Wort); if unavoidable, increase dose (see Adult). Antagonizes midazolam (CYP3A4 substrate), warfarin (CYP2C9 substrate), and omeprazole (CYP2C19 substrate). May antagonize concomitant drugs with narrow therapeutic indexes metabolized by CYP3A4 (eg, alfentanil, cyclosporine, dihydroergotamine, ergotamine, fentanyl, pimozide, quinidine, sirolimus, tacrolimus), CYP2C9 (eg, phenytoin, warfarin), CYP2C19 (eg, S-mephenytoin); avoid. Conduct more INR monitoring if concomitant warfarin cannot be avoided. Caution with concomitant drugs that may lower the seizure threshold.
Androgen receptor inhibitor.
Asthenia/fatigue, back pain, decreased appetite, constipation, arthralgia, diarrhea, hot flush, upper respiratory tract infection, peripheral edema, dyspnea, musculoskeletal pain, weight decreased, headache, hypertension, dizziness/vertigo; seizure, PRES.
Hepatic (CYP2C8, 3A4); 97–98% protein bound.
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