Memantine efficacy and safety in patients with acute mania associated with bipolar I disorder: a pilot evaluation

Evaluate the efficacy and tolerability of memantine (20, 30, and 40 mg/d) in the acute treatment of adults with bipolar I disorder hospitalized for mania. This multicenter, open-label, pilot trial included adults with bipolar I disorder (manic or mixed episode, with and without psychotic features). Patients were assigned to 21 days of treatment: cohort 1, 20 mg/d (range, 20-30 mg/d); cohort 2, 30 mg/d (range, 30-40 mg/d); cohort 3, 40 mg/d (range, 30-50 mg/d). Efficacy measures included the Young Mania Rating Scale (YMRS) and the Mania Rating Scale (>or=50% reduction in total score from baseline). The change from baseline was also assessed using the Positive and Negative Syndrome Scale in patients with psychiatric symptoms, Positive and Negative Syndrome Scale-Excited Component, Clinical Global Impression Severity and Improvement scores, and Montgomery Asberg Depression Rating Scale. A total of 35 patients were enrolled; 33 patients received at least 1 dose of memantine and had at least 1 postbaseline assessment using YMRS. Greatest improvement occurred in cohort 1 where half of the patients responded to memantine based on YMRS and Mania Rating Scale. At day 21, a response was observed in all patient cohorts. Treatment-emergent adverse events were reported in 19 patients (54.3%). The most frequently reported adverse events (>or=4 patients) included constipation, nausea, and headache. The response to memantine combined with its tolerability support conducting large-sized randomized controlled trials to investigate further the use of memantine monotherapy in the treatment of mania.