On-demand hyoscine butylbromide for the treatment of self-reported functional cramping abdominal pain

Objective. Hyoscine butylbromide (HBB) has been used for 60 years to treat cramping abdominal pain, but scientific evidence to support on-demand use is limited. The aim of this study was to identify a meaningful efficacy end point that differentiates between the effects of HBB (20-100 mg/day) and placebo when used on demand. Materials & methods. 175 patients were treated in a randomized, double-blind, placebo-controlled, two-arm parallel group study. After a 4-week run-in period, patients used HBB to treat 2 distinct episodes of abdominal pain associated with cramping (APC). Patients entered data into an electronic diary for up to 4 h/episode. Pain intensity was assessed using an 11-point numerical pain rating scale (NPRS). Patients were allowed to self-medicate with up to 4 additional doses of HBB every 30 min. Results. The adjusted mean difference for the change from baseline during the 4-h observation period for a reduction in abdominal pain was -0.7 (95% confidence interval (CI) -1.3, -0.1, p = 0.016) for episode 1 and -0.6 (95% CI -1.2, 0.0, p = 0.051) for episode 2. Patients in the HBB group recorded a clinically relevant reduction of at least 2 points on the NPRS (approximately 30% pain relief) earlier than patients in the placebo group (HBB: 45 min, placebo: 60 min). Reported adverse events were infrequent in both groups (10.2% and 10.3%). Conclusions. HBB is effective in the treatment of recurrent APC and is safe and well tolerated when used on demand. The change from baseline in the intensity of APC using the 11-point NPRS distinguished HBB from placebo.