(US Adopted Name, rINN)
INNs in other languages (French, Latin, and Spanish): Abarelix; Abanelixum; PPI-149; R-3827.
CAS — 183552-38-7
ATC — L02BX01
Adverse Effects and Precautions
Immediate hypersensitivity reactions, including urticaria, pruritus, hypotension, and syncope, can occur with abarelix, and the cumulative risk of such a reaction increases with repeated doses. Patients should be monitored for at least 30 minutes after each injection. Hot flushes, sleep disturbance, breast enlargement and tenderness may result from testosterone reduction. Prolongation of the QT interval has occurred in patients receiving abarelix.
Elevations in transaminase concentrations have occurred, and liver function should be monitored before starting treatment, and periodically during treatment. The effectiveness of abarelix in the management of prostate cancer decreases with duration of therapy, and may be further reduced in patients weighing more than about 100 kg (225 pounds). The serum concentration of testosterone should be measured on day 29 of therapy and then every 8 weeks, to monitor for treatment failure.
Abarelix is absorbed slowly after intramuscular injection, with a peak concentration in serum reached after about 3 days. It is metabolised by hydrolysis and has an elimination half-life of about 13 days with intramuscular use.
Uses and Administration
Like cetrorelix, abarelix is a gonadorelin (gonadotrophin-releasing hormone) antagonist. It is used to reduce testosterone concentrations in the palliative hormonal therapy of prostate cancer. A dose of abarelix 100 mg is given intramuscularly on days 1,15, and 29, and then every 4 weeks thereafter. Abarelix has been investigated for the treatment of endometrio-