Mirtazapine for treatment of nausea induced by selective serotonin reuptake inhibitors.

Dear Editor: Nausea appears to be a dosagerelated side effect in as many as 26% of patients treated with selective serotonin reuptake inhibitors (SSRIs) (1,2). SSRIs increase the concentration of serotonin (5-HT) at neuronal synapses. Emesis may result from subsequent activation of central or peripheral 5-HT3 receptors (2,3). Antagonism of 5-HT3 by drugs like ondansetron is known to reduce emesis in chemotherapy patients and may have some appl icat ion in SSRI-induced nausea, but the effect is short-lived and the cost is prohibitive (2,3). The 5-HT antagonist cyproheptadine may have some efficacy for SSRI-induced nausea, but it has been associated with worsening of depressive symptoms when used to treat SSRI-induced sexual dysfunction (4). The antidepressant mirtazapine, an antagonist at presynaptic alpha 2 adrenergic inhibitory autoreceptors and heteroreceptors (where it enhances noradrenergic and serotonergic activity), is also a potent antagonist of 5-HT2 and 5-HT3 receptors (5). We report a case of SSRI-induced nausea successfully treated with mirtazapine.