Paliperidone palmitate injection: Its efficacy, safety and tolerability in schizophrenia.

Intramuscular paliperidone palmitate is a long-acting atypical antipsychotic, which is currently marketed in the U.S. for the acute and maintenance treatment of schizophrenia in adults. Paliperidone is the active 9-hydroxy metabolite of risperidone. After intramuscular injection, paliperidone palmitate is slowly hydrolyzed to paliperidone with a mean half-life of 24-49 days, depending on the dose. Four randomized, double-blind, placebo-controlled trials of 9-13-weeks duration, demonstrated the efficacy of paliperidone palmitate (25-150 mg equivalents [eq.]) in improving the symptoms of acute exacerbation of schizophrenia. As maintenance therapy, paliperidone palmitate (25-100 mg eq.) was significantly more effective than placebo in delaying the time to first relapse in stable schizophrenia patients. Overall, paliperidone palmitate was shown to be well tolerated. It is available as prefilled syringes embracing a wide dose range (25, 50, 75, 100 and 150 mg eq.), and requires no refrigeration, reconstitution or oral antipsychotic supplementation.