Comparison of Metronidazole and Placebo in Control of Gaseous Symptoms: in Patients with Functional Bowel Disorders; A Randomized Double- blind Controlled Study

To compare the efficacy of metronidazole versus placebo in the control of gaseous symptoms inpatients with functional bowel disease. In the absence of organic or systemic diseases، all cases with chief complaints of bloating and normal laboratory tests were consecutively enrolled in this double-blind study. Lactase deficiency and bacterial overgrowth were ruled out by the lactose breath test. Patients were randomly assigned to receive either metronidazole or placebo. Demographic characteristics as well as frequency and severity of the patients'' scores (mean total symptom score) before and after therapy، their compliance and drug adverse effects were evaluated. A 50% decrease in the total symptom scores was defined as effective treatment. During one year، 46 patients (17 males، 29 females، mean age: 38. 9 ± 9. 9 years) were enrolled in the study. A total of 23 patients received metronidazole (cases) and 23 received placebo (controls). Two patients in the metronidazole group did not tolerate the drug and one patient in the placebo group did not continue with follow-up. Patients responded similarly to both regimens: 59% of patients in the placebo group and 52. 2% of patients in the metronidazole group had a 50% decrease in their total symptom score (p = 0. 64). Side effects of metronidazole were frequent، but tolerable. Bad taste in the mouth and anorexia were the most common complaints in the metronidazole group. This study showed no difference between placebo and metronidazole in relief of bloating and other related complaints in patients with functional bowel disease.