Senna Versus Magnesium Oxide for the Treatment of Chronic Constipation: A Randomized, Placebo-Controlled Trial

INTRODUCTION: This is the first prospective, double-blinded, randomized, placebo-controlled trial to evaluate the safety and efficacy of a stimulant laxative compared with an osmotic agent for the treatment of chronic idiopathic constipation. METHODS: Patients were randomly administered stimulant laxative (senna, 1.0 g), osmotic agent (magnesium oxide [MgO], 1.5 g), or placebo for 28 consecutive days. The primary endpoint was overall symptom improvement. Secondary endpoints were spontaneous bowel movement (SBM), complete SBM, and patient assessment of constipation quality of life (QOL). RESULTS: Ninety patients (mean age, 42 years; 93% women; mean duration of symptoms, 9.9 years) were enrolled; all completed the study. The response rate for overall improvement was 11.7% in the placebo group, 69.2% in the senna group, and 68.3% in the MgO group (P < 0.0001). Change in SBM was significantly greater in the senna and MgO groups than that in the placebo group (P < 0.001). Similarly, change in complete SBM was significantly greater in the senna and MgO groups than that in the placebo group (P < 0.01). On the patient assessment of constipation QOL, significant improvements were seen in the senna and MgO groups compared with those in the placebo group (senna, P < 0.05; MgO, P < 0.001). The frequency of severe treatment-related adverse events was 0%. DISCUSSION: Senna and MgO significantly improved the frequency of bowel movements and QOL score and seem to be effective in the treatment of constipation.