Minimal injection site pain and high patient satisfaction during treatment with long-acting risperidone

Long-acting injectable antipsychotic formulations of conventional antipsychotics were developed to address the problem of partial adherence among patients with schizophrenia. Injection site pain, other skin reactions and patient satisfaction with treatment were assessed in two large, multicentre studies of long-acting injectable risperidone (Risperdal CONSTA, Janssen Pharmaceutica Products, Titusville, New Jersey, USA), the first available long-acting atypical antipsychotic agent. Patients rated injection site pain using a 100-mm Visual Analogue Scale (VAS), and investigators rated injection site pain, redness, swelling and induration. Patient satisfaction with treatment was assessed with the Drug Attitude Inventory (DAI). VAS pain ratings were low at all visits across all doses in both studies, and decreased from first to final injection. In the 12-week, double-blind study, mean +/- SD VAS scores at the first and final injections were 15.6 +/- 20.7 and 12.5 +/- 18.3 for placebo-treated patients, and 11.8 +/- 14.4 (first) and 10.0 +/- 12.4 (final) for 25 mg; 16.3+/-21.9 (first) and 13.6 +/- 21.7 (final) for 50 mg; and 16.0 +/- 17.9 (first) and 9.6 +/- 16.0 (final, P<0.01) for 75 mg of long-acting risperidone. Mean VAS scores in the 50-week, open-label study at the first and final injection were: 17.9 +/- 22.2 (first) and 9.5 +/- 16.7 (final, P<0.0001) for 25 mg; 18.1 +/- 19.7 (first) and 10.4 +/- 14.8 (final, P<0.0001) for 50 mg; and 18.5 +/- 21.6 (first) and 13.6 +/- 19.9 (final, P = 0.0001) for 75 mg of long-acting risperidone. Overall, there was no or minimal injection site pain and skin reactions were rare. Mean DAI ratings were available for the 50-week study and indicated high patient satisfaction throughout the trial (baseline = 7.30; endpoint = 7.70; P<0.0001 versus baseline). These findings may positively affect patient and clinician attitudes towards long-term therapy with long-acting injectable risperidone.