Orlistat in clozapine- or olanzapine-treated patients with overweight or obesity: a 16-week open-label extension phase and both phases of a randomized controlled trial

Abstract

Objective: To explore long-term effects of orlistat in adult clozapine- or olanzapine-treated patients with DSM-IV-diagnosed schizophrenia and overweight or obesity who tolerate orlistat.

Method: Orlistat or placebo was added to clozapine or olanzapine in stable doses in a 16-week randomized controlled trial. Open-label orlistat was added to the antipsychotics during a 16-week extension phase for those completing the double-blind phase. No low-calorie diet or participation in behavioral programs was required. Body weight (primary outcome) and some metabolic parameters were measured prospectively. Analyses were performed for those completing both phases (ie, population differing from that reported earlier). The study was conducted from 2004 through 2005.

Results: During the open-label phase, the 44 patients experienced mean ± SD body weight loss of -1.29 ± 3.04 kg, P = .007. During both phases, men (but not women) showed a weight loss of -2.39 ± 5.45 kg, P = .023. Some subgroups showed desirable changes in several metabolic parameters. Prolonged (32 weeks) orlistat treatment yielded no additional benefits as compared to short (16 weeks) treatment.

Conclusions: In clozapine- or olanzapine-treated overweight or obese patients able to take orlistat on a long-term basis, the drug, with no concomitant hypocaloric diet or behavioral interventions, caused moderate weight loss only in men. However, some metabolic benefits may be achieved independently of weight changes. In patients who do not respond to orlistat within the first 16 weeks, continuation treatment may provide no additional benefits.

Trial registration: controlled-trials.com Identifier: ISRCTN65731856.