Injectable risperidone effective against acutely exacerbated schizophrenia

Use of long-acting injectable risperidone appears to produce rapid and progressive reduction in symptoms of schizophrenia patients with acute exacerbation, eliminating the need for oral risperidone supplementation or loading doses, according to a study.

In total, 390 patients (mean age, 42 years; 67 percent male; mean body mass index, 28.33 kg/m²) were randomized to receive once-monthly intramuscular injections of long-acting risperidone (75 mg or 100 mg) or placebo for 12 weeks. Treatment was administered every 4 weeks, on days 1, 29, and 57.

The mean Positive and Negative Syndrome Scale (PANSS) score at baseline was 96.4 in the 75-mg group, 96.3 in the 100-mg group, and 96.1 in the placebo group. At day 85, active treatment yielded a significant improvement in the PANSS total score, with placebo-adjusted differences of −13.0 (95 percent confidence interval [CI], −17.3 to −8.8; p<0.0001) with the 75-mg dose and −13.3 (95 percent CI, −17.6 to −8.9; p<0.0001) with the 100-mg dose.

Risperidone was also associated with marked improvements in Clinical Global Impressions-Severity of Illness scale (CGI-S) score compared with placebo (p<0.0001 for both doses).

The improvements in the efficacy outcomes were seen as early as 8 days after the first injection.

Both doses were well tolerated. The most common treatment-emergent adverse events were increased blood prolactin (7.8 percent), headache (7.3 percent), hyperprolactinemia (5 percent), and weight gain (4.8 percent). There were no reports of new or unexpected safety signals.

The findings suggest that injectable risperidone can be an effective therapeutic strategy for schizophrenia patients suffering from an acute episode with severe or moderate psychotic symptoms.