The role of NMDA receptor antagonists, amantadine and memantine, in schizophrenia treatment: a systematic review

Abstract Objective Schizophrenia is a complex and chronic psychiatric disorder. In recent years, studies have found glutamatergic system participation in its etiopathogenesis, especially through aberrant NMDA receptors functioning. Thus, drugs that modulate this activity, as amantadine and memantine, could theoretically be used in its treatment. To perform a systematic literature review about memantine and amantadine use as adjunct in schizophrenia treatment. Methods A systematic review of papers published in English indexed in the electronic database PubMed ® using the terms "memantine", "amantadine" and "schizophrenia" published until October 2016. Results We found 144 studies, 8 selected for analysis due to meet the objectives of this review. Some of these have shown benefits from such drug use, especially in symptoms measured by PANSS and its subdivisions, while others do not. Discussion: The data in the literature about these drugs use for schizophrenia treatment is still limited and have great heterogeneity. Thus, assay with greater robustness are needed to assess real benefits of these drugs as adjuvant therapy.

Efficacy of memantine in acute non-arteritic ischemic optic neuropathy

Evaluation of efficacy of Memantine [N-Methyl-D-Aspartate Receptor Antagonist] on visual function of patients with acute non-arteritic ischemic optic neuropathy [NAION]. The study was conducted as interventional case series from November 2005 through November 2006 in Farabi Eye Hospital. Twenty-two patients with acute NAION of less than 8 weeks duration entered the study. Memantine was prescribed with a dose of 5 mg per day for the first week and 10 mg per day for the following two weeks. Baseline best corrected visual acuity [BCVA]; visual evoked potential [VEP] and visual field was done for all patients. BCVA recording repeated 3 weeks, 3 and 6 months later. VEP and perimetry repeated 3 months after treatment. After 3 weeks, 3 and 6 months, BCVA improved -0.32 +/- 0.40 LogMAR, -0.51 +/- 0.49 and -0.51 +/- 0.49, respectively [P=0.005, P=0.001 and P=0.001, respectively]. VEP recordings after 3 months, demonstrated -8.61 +/- 14.51 db mean decrease in implicit time [P=0.019]. Amplitude of voltage did not show significant difference with baseline [P=0.10]. Perimetry results after 3 months showed that mean deviation [MD] improved 2.77 +/- 3.94 db [P=0.016]. Memantine resulted in significant improvement of BCVA 3 weeks, 3 and 6 months after treatment of acute NAION. Memantine also resulted in significant decrease of implicit time and significant improvement of mean deviation in VEP and perimetry after 3 months