e 3–4
(%)
High Triglyceride 62.5 0.4 53.0 0
High AST 30.6 2.1 36.3 1.5
Low Potassium 28.3 5.3 19.8 1.0
Low Phosphorus 23.8 7.2 15.7 5.8
High ALT 11.1 1.4 10.4 0.8
High Total Bilirubin 6.6 0.1 4.6 0
7 DRUG INTERACTIONS
7.1 Effects of Abiraterone on Drug Metabolizing Enzymes
ZYTIGA is an inhibitor of the hepatic drug-metabolizing enzyme CYP2D6. 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 abiraterone acetate 1,000 mg daily and prednisone 5 mg twice daily. Avoid co-administration of abiraterone acetate with substrates of CYP2D6 with a narrow therapeutic index (e.g., thioridazine). If alternative treatments cannot be used, exercise caution and consider a dose reduction of the concomitant CYP2D6 substrate drug [see Clinical Pharmacology (12.3)].
7.2 Drugs that Inhibit or Induce CYP3A4 Enzymes
Based on in vitro data, ZYTIGA is a substrate of CYP3A4. The effects of strong CYP3A4 inhibitors (e.g., ketoconazole, itraconazole, clarithromycin, atazanavir, nefazodone, saquinavir, telithromycin, ritonavir, indinavir, nelfinavir, voriconazole) or inducers (e.g., phenytoin, carbamazepine, rifampin, rifabutin, rifapentine, phenobarbital) on the pharmacokinetics of abiraterone have not been eva luated, in vivo. Avoid or use with caution, strong inhibitors and inducers of CYP3A4 during ZYTIGA treatment [see Clinical Pharmacology (12.3)].
8 USE IN SPECIFIC POPULATIONS
8.1 Pregnancy
Pregnancy Category X [see Contraindications (4.1)].
ZYTIGA is contraindicated in women who are or may become pregnant while receiving the drug. If this drug is used during pregnancy, or if the patient becomes pregnant while taking this drug, the patient should be apprised of the potential hazard to the fetus and the potential risk for pregnancy loss. Women of childbearing potential should be advised to avoid becoming pregnant during treatment with ZYTIGA.
8.3 Nursing Mothers
ZYTIGA is not indicated for use in women. It is not known if abiraterone acetate is excreted in human milk. Because many drugs are excreted in human milk, and because of the potential for serious adverse reactions in nursing infants from ZYTIGA, a decision should be made to either discontinue nursing, or discontinue the drug taking into account the importance of the drug to the mother.
8.4 Pediatric Use
ZYTIGA is not indicated in children.
8.5 Geriatric Use
Of the total number of patients in a phase 3 trial of ZYTIGA, 71% of patients were 65 years and over and 28% were 75 years and over. No overall differences in safety or effectiveness were observed between these elderly patients and younger patients.
8.6 Patients with Hepatic Impairment
The pharmacokinetics of abiraterone were examined in subjects with baseline mild (n = 8) or moderate (n = 8) hepatic impairment (Child-Pugh Class A and B, respectively) and in 8 healthy control subjects with normal hepatic function. The systemic exposure (AUC) of abiraterone after a single oral 1,000 mg dose of ZYTIGA increased by approximately 1.1-fold and 3.6-fold in subjects with mild and moderate baseline hepatic impairment, respectively compared to subjects with normal hepatic function.
No dosage adjustment is necessary for patients with baseline mild hepatic impairment. In patients with baseline moderate hepatic impairment (Child-Pugh Class B), reduce the recommended dose of |
