Levomilnacipran for the treatment of major depressive disorder: a review

Levomilnacipran (LVM, Fetzima(®)) was recently approved by the US Food and Drug Administration for the treatment of major depressive disorder. It is a unique dual neurotransmitter reuptake inhibitor. In contrast with other selective serotonin norepinephrine reuptake inhibitors, including duloxetine, venlafaxine, and desvenlafaxine, it has greater selectivity for inhibiting norepinephrine reuptake than serotonin reuptake. Our review focuses on the efficacy, safety, and tolerability data for five double-blind, placebo-controlled, short-term studies and two long-term studies. In the short-term studies, LVM was found to be more effective than placebo in reducing depression (Montgomery-Åsberg Depression Rating Scale) scores as well as improving functional impairment (Sheehan Disability Scale) scores. Long-term studies found LVM to be similarly effective but in the only placebo-controlled long-term study, LVM was not significantly superior to placebo. LVM is fairly well tolerated, with the most common adverse events being nausea, headache, dry mouth, hyperhidrosis, and constipation. Discontinuation rates were mildly increased in those being treated with LVM (9%) versus placebo (3%). Adverse events were not dose-related except for urinary hesitancy and erectile dysfunction. LVM was weight neutral, was not toxic to the liver, and did not cause clinically significant QTc prolongation. Consistent with being a predominant potentiator of norepinephrine, pulse and blood pressure were significantly elevated by LVM but rarely induced tachycardia or hypertension. LVM is a relatively safe alternative antidepressant treatment with minimal drug–drug interactions. It is the only antidepressant that has in its labeling that it is not only effective in improving depression but also effective in improving impaired functioning. Whether this important effect on functioning is unique to LVM must be researched. In addition, whether LVM might be effective in norepinephrine-deficit depression, refractory depression, atypical depression, or seasonal depression is yet to be evaluated. Ultimately, head-to-head studies comparing LVM with other antidepressants will determine the place of LM in antidepressant treatment.