Product Information
Registration Status: ActiveSIN15345P
ZYTIGA FILM-COATED TABLET 500MG is approved to be sold in Singapore with effective from 2017-10-16. It is marketed by JOHNSON & JOHNSON PTE LTD, with the registration number of SIN15345P.
This product contains Abiraterone 500mg in the form of TABLET, FILM-COATED. It is approved for ORAL use.
This product is manufactured by Patheon France S.A.S in FRANCE, andJanssen-Cilag SpA (Primary and Secondary Packager) in ITALY.
It is a Prescription Only Medicine that can only be obtained from a doctor or a dentist, or a pharmacist with a prescription from a Singapore-registered doctor or dentist.
Product Reference
Important Note: For generic product, the SPC/PIL provided may not be brand specific.
{{/items}} {{^items}}Description
Abiraterone is a derivative of steroidal progesterone and is an innovative drug that offers clinical benefit to patients with hormone refractory prostate cancer. Abiraterone is administered as an acetate salt prodrug because it has a higher bioavailability and less susceptible to hydrolysis than abiraterone itself. FDA approved on April 28, 2011.
Indication
Used in combination with prednisone for the treatment of metastatic, castration-resistant prostate cancer.
Mechanism of Action
Abiraterone is an orally active inhibitor of the steroidal enzyme CYP17A1 (17 alpha-hydroxylase/C17,20 lyase). It inhibits CYP17A1 in a selective and irreversible manner via covalent binding mechanism. CYP17A1 is an enzyme that catalyzes the biosynthesis of androgen and is highly expressed in testicular, adrenal, and prostatic tumor tissue. More specifically, abiraterone inhibits the conversion of 17-hydroxyprognenolone to dehydroepiandrosterone (DHEA) by the enzyme CYP17A1 to decrease serum levels of testosterone and other androgens.
Pharmacokinetics
- Absorption
- Abiraterone itself is poorly absorbed and is susceptible to hydrolysis by esterases. The salt form, abiraterone acetate, is a prodrug which has a much higher oral bioavailability and is also esterase resistant. Peak drug concentrations of abiraterone were reached in 1.5 - 4 hours. Abiraterone acetate was rapidly and completely deacetylated into abiraterone-the parent salt form was not detectable in early pharmacokinetic studies. Food and high fat meals increases absorption 4.4-fold.
- Distribution
- Vdss= 19,669 ± 13,358 L
- Metabolism
- Abiraterone acetate is hydrolyzed into active metabolite abiraterone via esterases. CYP3A4 and SULT2A1 further metabolizes abiraterone into two inactive metabolites called abiraterone sulfate and N-oxide abiraterone sulfate.
- Elimination
Toxicity
Toxicity is related to the blockade of 17α-hydroxylase activity. Blockade results in the accumulation of upstream mineralocorticoids like 11-deoxycorticosterone leading to secondary hyperaldosteronism. Signs of hydroaldosteronism include fluid retention and hypokalemia. Mineralocorticoid receptor antagonists may be used to treat signs and symptoms.
Active Ingredient/Synonyms
(3β)-17-(pyridin-3-yl)androsta-5,16-dien-3-ol | 17-(3-Pyridyl)androsta-5,16-dien-3beta-ol | Abiraterone |
Source of information: Drugbank (External Link). Last updated on: 3rd July 18. *Trade Name used in the content below may not be the same as the HSA-registered product.