IMPROVEMENTS in many symptoms of functional dyspepsia have been observed in a pilot study of mirtazapine, an antidepressant.
Functional dyspepsia is a highly prevalent gastrointestinal disorder and can present with early satiation, postprandial fullness, and epigastric pain and burning in the absence of underlying systemic or metabolic disease. The most worrying symptom is weight loss, which occurs in up to 40% of patients. Current treatments for functional dyspepsia include acid-suppressive and prokinetic drugs; these can improve gastric accommodation but it is not known if they carry any benefit for other symptoms. The antidepressant, mirtazapine, often causes weight gain in patients being treated for depression. This led to the design of a trial to assess its efficacy as a treatment for functional dyspepsia patients with weight loss.
Mirtazapine acts as an antagonist at H1, α2, 5-hydroxytryptamine 2C (5-HT2C) and 5-HT3receptors. In the trial, 34 patients with functional dyspepsia and weight loss of >10% were randomised to either a dose of 15 mg mirtazapine every evening, or to placebo. The results showed that whilst the average weight on placebo was almost unchanged, the average weight on mirtazapine increased by 2.5±0.6 kg at Week 4 and 3.9±0.7 kg (6.4% of original body weight) by Week 8.
Patients on mirtazapine also reported an improvement in mean dyspepsia symptom severity questionnaire score at Weeks 4 and 8, a finding that was not seen in patients on placebo. Other symptoms that were potentially improved were early satiety, quality of life, gastrointestinal specific-anxiety, and nutrient tolerance. However, there appeared to be no changes in epigastric pain or gastric emptying and little effect on postprandial fullness. It was also noted that of the 17 patients randomised to mirtazapine, 2 dropped out due to drowsiness, a common side effect of the medication.
Further research is needed to elucidate the full benefits and harms of mirtazapine, although these results are promising. Prof Jan Tack, Faculty of Medicine, University of Leuven, Leuven, Belgium, said: “[Mirtazapine] has the potential to become the treatment of choice for functional dyspepsia in patients with weight loss, and evaluation in larger multicentre studies is warranted.”