Imipramine, a tricycle antidepressant (TCA), has no superiority over placebo in achieving satisfactory relief of reflux symptoms in esophageal hypersensitivity patients. The findings come from a new, first-of-its-kind study which tested imipramine versus a placebo on 83 patients with nonerosive reflux disease (NERD). Patients were deemed to have esophageal hypersensitivity based on the 24-h MII-pH test.
Forty-three of these participants were administered 25mg of imipramine, daily over 8-weeks, while 40 counter parts received placebo. The full findings of the study are published in the American Journal of Gastroenterology.
Results showed no statistical significance in the number of responders defined as having a >50% improvement of gastroesophageal reflux disease (GERD) score from baseline, from either imipramine or placebo group. Researchers used different cutoff values for determining responders including, any degree of improvement, improvement of >25% from baseline, and improvement from >75% from baseline, and these results still showed no differences between the imipramine and placebo group.
Despite there being no difference in symptomatic responses from the imipramine and placebo groups, the per-protocol analysis indicated that those receiving imipramine were considerably more likely to experience improvements in quality-of-life (QoF), than those receiving placebo. This score increased from 60 to 72 in the imipramine group and from 55 to 61 in the placebo group ( P =0.048). Safety and tolerability showed no serious adverse events, apart from constipation noted in the imipramine group.
The underlying symptom mechanisms of esophageal hypersensitivity remain unclear and physiological tests have shown that NERD patients are very diverse in their physiological characteristics. Patients can be divided into subgroups: those with abnormal acid reflux, with abnormal non-acid reflux, and without abnormal reflux.
Antidepressants have been demonstrated to have beneficial effects in functional gastrointestinal disorders, leading authors of this study to hypothesize that similar beneficial effects could aid symptoms of esophageal hypersensitive esophagus. However, the authors conclude that their findings suggest tricycle antidepressants present no benefit in treatment of a NERD subtype characterized by esophageal hypersensitivity.
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