Efficacy of Mirtazapine in Patients With Functional Dyspepsia and Weight Loss

Background & aims: A subset of patients with functional dyspepsia (FD) present with early satiation and weight loss, for which there are no established therapeutic options. We investigated the efficacy of mirtazapine (an antidepressant and antagonist of the histamine receptor H1, the α2 adrenergic receptor, and the serotonin receptors 5-HT2C and 5-HT-3) in patients with FD and weight loss.

Methods: We conducted a randomized, placebo-controlled pilot trial that studied 34 patients with FD (29 women; mean age, 35.9 ± 2.3 years) with weight loss >10% of original body weight (mean loss, 12.4 ± 2.3 kg) without depression or anxiety. After a run-in period, patients were randomly assigned to groups given placebo (n = 17) or mirtazapine 15 mg each day for 8 weeks (n = 17) in a double-blind manner. Subjects were evaluated during a 2-week baseline and 8-week treatment for dyspepsia symptom severity, quality of life (on the basis of the Nepean Dyspepsia Index), and gastrointestinal-specific anxiety; they were given a nutrient challenge test and weighed. Data were analyzed by using linear mixed models, followed by planned contrasts with adaptive step-down Bonferroni multiple testing correction.

Results: Two patients in each group dropped out. At weeks 4 and 8, mirtazapine significantly reduced mean dyspepsia symptom severity scores compared with week 0 (P = .003 and P = .017, respectively); there was no significant reduction in the placebo group (P > .37 for weeks 4 and 8). The difference in change from week 0 between mirtazapine and placebo showed a trend with a large effect size at week 4 (P = .059) that was not significant at week 8 (P = .55). However, improvements from week 0 to weeks 4 and 8 were significantly larger in the mirtazapine group than placebo group for early satiation, quality of life, gastrointestinal-specific anxiety, weight, and nutrient tolerance (mostly with large effect sizes).

Conclusions: In a randomized, placebo-controlled trial, mirtazapine significantly improved early satiation, quality of life, gastrointestinal-specific anxiety, nutrient tolerance, and weight loss in patients with FD. ClinicalTrials.gov number: NCT01240096.