Article date: March 2011
By: Samir Kumar Praharaj, Amlan Kusum Jana, Nishant Goyal, Vinod Kumar Sinha, in Volume 71, Issue 3, pages 377-382
WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT
• Olanzapine in an atypical antipsychotic agent which is associated with significant weight gain.
• Metformin, an anti‐hyperglycaemic agent, has been used to treat or prevent weight gain associated with olanzapine.
• Meta‐analyses on studies that have examined the use of metformin for treatment of antipsychotic‐induced weight gain report significant heterogeneity.
WHAT THIS STUDY ADDS
• Systematic review and meta‐analysis showed that metformin is useful for the short‐term treatment of olanzapine‐induced weight gain.
Olanzapine is an atypical antipsychotic that is useful in schizophrenia and bipolar affective disorder, but its use is associated with troublesome weight gain and metabolic syndrome. A variety of pharmacological agents has been studied in the efforts to reverse weight gain induced by olanzapine, but current evidence is insufficient to support any particular pharmacological approach. We conducted a systematic review and meta‐analysis of randomized controlled trials of metformin for the treatment of olanzapine‐induced weight gain. Systematic review of the literature revealed 12 studies that had assessed metformin for antipsychotic‐induced weight gain. Of these, four studies (n= 105) met the review inclusion criteria and were included in the final analysis. Meta‐analysis was performed to see the effect size of the treatment on body weight, waist circumference and body‐mass index (BMI). Weighted mean difference (WMD) for body weight was 5.02 (95% CI 3.93, 6.10) kg lower with metformin as compared with placebo at 12 weeks. For waist circumference, the test for heterogeneity was significant (P= 0.00002, I2= 85.1%). Therefore, a random effects model was used to calculate WMD, which was 1.42 (95% CI 0.29, 3.13) cm lower with metformin as compared with placebo at 12 weeks. For BMI, WMD was 1.82 (95% CI 1.44, 2.19) kg m−2 lower with metformin as compared with placebo at 12 weeks. Existing data suggest that short term modest weight loss is possible with metformin in patients with olanzapine‐induced weight gain.
DOI: 10.1111/j.1365-2125.2010.03783.x
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