Effect of memantine on C-reactive protein and lipid profiles in bipolar disorder

BACKGROUND: Balance in the immune system plays roles in bipolar disorder (BD) and its metabolic co-morbidities. Memantine is an NMDA receptor antagonist with anti-inflammatory effects. However, the effects of memantine adjunct treatment on metabolic status of BD are unclear. METHODS: During the 12 weeks period, a total of 191 BD patients were enrolled and split into valproate (VPA) + placebo and VPA + memantine (5 mg/day) arms. The fasting plasma levels of high-sensitivity C-reactive protein (CRP) and metabolic indices were assessed. BD patients were stratified according to their initial CRP level. RESULTS: A cut-off value of initial CRP level of 2322 ng/mL discriminated the waist circumference in these BD patients after 12-week VPA treatment. In the high CRP (> 2322 ng/mL) group, patients in the VPA + memantine arm had a significantly decreased in their CRP (p= 0.009), total cholesterol (p= 0.002), LDL (p= 0.002) levels, BMI (p= 0.001), and waist circumference (p< 0.001), compared to those in the VPA + placebo arm. However, analysis of the low CRP group did not showed the effect. LIMITATIONS: We recruited BD patients in depressed states and the sample size was relative small. The effects of the fixed dose of memantine on metabolic indices were 12-week follow up in BD patients treated with VPA. CONCLUSIONS: BD patients with high initial CRP levels receiving memantine adjunct treatment have a reduced risk of inflammation and metabolic imbalance. Prospective studies are needed to confirm the long-term outcome for memantine adjunct therapy in BD patients.