Metformin addition therapy attenuates olanzapine-induced weight gain

Abstract

Objective The purpose of this study was to assess the efficacy of metformin in preventing olanzapine-induced weight gain and glucose metabolic dysfunction.Methods In the 12 week placebo-controlled study,37 drug-naive schizophrenic patients were randomly divided into two treatment groups,one with olanzapine(15 mg/d)plus metformin(750 mg/d)(n=18),one with olanzapine(15 mg/d)plus placebo(n=19).The body weight,body mass index(BMI),waist circumference,hip circumference,waist-hip-ratio(WHR),fasting glucose and insulin,insulin resistance index (IRI)was measured.The symptom Was assessed with the Scale for the Assessment of Positive Symptoms (SAPS)and Scale for the Assessment of Negative Symptoms(SANS).Results There was a significant inerease in body weight and BMI within each group from baseline to week 12[metformin group of(1.90±2.72)kg and (0.54±0.92)kg/m2;placebo group of(6.87±4.23)kg and(2.26±1.12)kg/m2](P<0.05).The increase in weight,BMI,WHR,insulin anti IRI values in placebo group was more than that in metformin group(P<0.05).The lower rate of weight increase of more than 7%from baseline to 12 week was in metformin group than in placebo group(17%vs.63%;P<0.01).Conclusion Metformin addition therapy is effective and safe in attenuating olanzapine-induced weight gain and insulin resistance in drugnaive schizophrenia patients.