Weight gain, risperidone and aripiprazole, and metformin

Weight increase with risperidone and aripiprazole neutralized by treatment with the diabetes drug metformin.

Risperidone (Risperdal) and aripiprazole (Abilify) are antipsychotic medications that have been approved by the Federal Drug Administration (U.S.) to treat irritability, aggression, and agitation in children with ASD. However,  either of these antipsychotic medications can increase weight, which is a risk factor for diabetes.

Metformin, a diabetes drug, was examined in a 16-week randomized placebo-controlled clinical trial for its effect on maintenance or reduction of weight gain. The study participants were 61 children and adolescents with ASD aged 6 to 17 years, randomized to receive metformin or placebo.

The study results indicated that metformin was significantly more effective than placebo in reducing weight gain experienced in the children with ASD who were treated with risperidone or aripirazole. Children who received metformin experienced declines in body mass index (BMI), a measure of weight adjusted for height, during the trial. Children who received placebo showed no declines in BMI from baseline. Overall, adverse events did not differ according to metformin or placebo treatment, with the exception of more frequent days of gastric symptoms among children who received metformin than children who received the placebo.

The ability of metformin to prevent weight gain offers greater flexibility for prescribing risperidone or aripiprazole for children with autism who experience significant weight gain during the drug treatment.

Reference: Anagnostou E, Aman MG, Handen B. Metformin for treatment of overweight induced by atypical antipsychotic medication in young people with autism spectrum disorder. A randomized clinical trial. Anagnostou, E., Aman MG, Handen BL et al. JAMA Pschiatry. Published online August 24, 2016. doi:10.1001/jamapsychiatry.2016.