Amantadine treatment of psychotropic-induced weight gain in children and adolescents: Case series

Objective: The purpose of this study was to explore whether amantadine would slow or reverse significant weight gain in children and adolescents treated with antipsychotics and/or mood stabilizers that may promote increases in weight. Methods: Eight boys and one girl ages 9-16 years and their parents consented to an open trial of amantadine 100 mg po bid or tid for weight gain in children. Side effects and body mass index were determined at baseline and during amantadine treatment. Results: A mean weight gain of 10.5 kg (19.9% mean increase in body weight) occurred from baseline to the beginning of amantadine treatment. Amantadine trial length averaged 14.5 weeks (range 4-33 weeks). A planned comparison using repeated measures analysis of variance demonstrated strong support for a "slowing weight gain" mechanism (p = 0.001) for weight gain and body mass. Weight loss was strongly correlated with length of amantadine treatment (p = < 0.05). One child experienced orthostatic hypotension with concomitant stimulant medication. No other side effects or exacerbation of psychiatric symptoms was reported. Conclusions: Amantadine appears to stabilize weight gain related to psychotropic medications. Decreased weight and body mass index may occur with continued amantadine usage. Controlled trials of amantadine in children and adolescents taking weight-gain-inducing psychotropics are warranted.