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

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.

During the 12 weeks period, a total of 191 BD patients were enrolled and split into valproate (VPA) + placebo and VPA + memantine (5mg/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.

A cut-off value of initial CRP level of 2322ng/mL discriminated the waist circumference in these BD patients after 12-week VPA treatment. In the high CRP (> 2322ng/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.

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.

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.