Zytiga Dosage/Direction for Use

Posology: The recommended dose is 1000 mg (two 500 mg tablets or four 250 mg tablets) as a single daily dose that must not be taken with food (see Method of administration as follows). Taking the tablets with food increases systemic exposure to abiraterone (see Interactions, and Pharmacology: Pharmacokinetics under Actions).
Dosage of prednisone or prednisolone: For mCRPC, ZYTIGA is used with 10 mg prednisone or prednisolone daily.
For mHSPC, ZYTIGA is used with 5 mg prednisone or prednisolone daily.
Medical castration with LHRH analogue should be continued during treatment in patients not surgically castrated.
Recommended monitoring: Serum transaminases should be measured prior to starting treatment, every two weeks for the first three months of treatment and monthly thereafter. Blood pressure, serum potassium and fluid retention should be monitored monthly. However, patients with a significant risk or congestive heart failure should be monitored every 2 weeks for the first three months of treatment and monthly thereafter (see Precautions).
In patients with pre-existing hypokalaemia or those that develop hypokalaemia whilst being treated with ZYTIGA, consider maintaining the patient's potassium level at ≥ 4.0mM.
For patients who develop Grade ≥ 3 toxicities including hypertension, hypokalaemia, oedema and other non-mineralocorticoid toxicities, treatment should be withheld and appropriate medical management should be instituted. Treatment with ZYTIGA should not be reinitiated until symptoms of the toxicity have resolved to Grade 1 or baseline.
In the event of a missed daily dose of either ZYTIGA, prednisone or prednisolone, treatment should be resumed the following day with the usual daily dose.
Hepatotoxicity: For patients who develop hepatotoxicity during treatment (alanine aminotransferase [ALT] increases or aspartate aminotransferase [AST] increases above 5 times the upper limit of normal [ULN]), treatment should be withheld immediately (see Precautions). Re-treatment following return of liver function tests to the patient's baseline may be given at a reduced dose of 500 mg (one 500 mg tablet or two 250 mg tablets) once daily. For patients being re-treated, serum transaminases should be monitored at a minimum of every two weeks for three months and monthly thereafter. If hepatotoxicity recurs at the reduced dose of 500 mg daily, treatment should be discontinued.
If patients develop severe hepatotoxicity (ALT or AST 20 times the upper limit of normal) anytime while on therapy, treatment should be discontinued and patients should not be re-treated.
Hepatic impairment: No dose adjustment is necessary for patients with pre-existing mild hepatic impairment, Child-Pugh Class A.
Moderate hepatic impairment (Child-Pugh Class B) has been shown to increase the systemic exposure to abiraterone by approximately four-fold following single oral doses of abiraterone acetate 1000 mg (see Pharmacology: Pharmacokinetics under Actions). There are no data on the clinical safety and efficacy of multiple doses of abiraterone acetate when administered to patients with moderate or severe hepatic impairment (Child-Pugh Class B or C). No dose adjustment can be predicted. The use of ZYTIGA should be cautiously assessed in patients with moderate hepatic impairment, in whom the benefit clearly should outweigh the possible risk. ZYTIGA should not be used in patients with severe hepatic impairment (see Contraindications, Precautions and Pharmacology: Pharmacokinetics under Actions).
Renal impairment: No dose adjustment is necessary for patients with renal impairment (see Pharmacology: Pharmacokinetics under Actions). However, there is no clinical experience in patients with prostate cancer and severe renal impairment. Caution is advised in these patients (see Precautions).
Paediatric population: There is no relevant use of this medicinal product in the paediatric population, as prostate cancer is not present in children and adolescents.
Method of administration: ZYTIGA is for oral use.
The tablets must be taken as a single dose once daily on an empty stomach. ZYTIGA must be taken at least two hours after eating and food must not be eaten for at least one hour after taking ZYTIGA. ZYTIGA tablets must be swallowed whole with water.