Amantadine for weight gain associated with olanzapine treatment

Patients with schizophrenia (Sch), schizoaffective, schizophreniform, or bipolar (BP) I disorders [Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV)]; not manic or acutely psychotic [Brief Psychiatric Rating Scale (BPRS) total score less than or equal to45]; treated with olanzapine for 1-24 months; and who had gained greater than or equal to5% of their initial body weight were examined to determine whether amantadine could attenuate weight gain or promote weight loss. Olanzapine (Olz; 5-20 mg/day) was co-administered with double-blind treatment of 100-300 mg/day amantadine (Olz+Amt, n=60) or placebo (Olz+Plc, n=65). Visit-wise analysis of weight showed that weight change from baseline [last-observation-carried-forward (LOCF)] in the Olz+Amt group was significantly different from the Olz+Plc group at weeks 8 (P=0.042), 12 (P=0.029), and 16 (primary endpoint, mean+/-S.D.: -0.19+/-4.58 versus 1.28+/-4.26 kg, P=0.045). Mean BPRS total score, positive subscale, and anxiety-depression scores improved comparably in both groups, and Montgomery-Asberg Depression Rating Scale (MADRS) total score improved in the Olz+Amt group. Overall, amantadine was safe, was well tolerated, and attenuated weight gain or promoted weight loss in some patients who had gained weight during olanzapine therapy. (C) 2004 Elsevier B.V. and ECNP. All rights reserved.