Randomised clinical trial: pregabalin vs placebo for irritable bowel syndrome

Background: Pregabalin is a calcium channel α2δ ligand that modifies visceral hypersensitivity in IBS patients. Clinical data for pregabalin in IBS are lacking. Aim: To test the efficacy of pregabalin on gastrointestinal symptoms in IBS patients. Methods: A double-blind, placebo-controlled trial was performed. Adults meeting IBS Rome III criteria with ≥3 pain attacks per month were randomised to pregabalin 225 mg vs placebo twice daily for 12 weeks. Questionnaires were completed weekly. The primary endpoint was average pain Bowel Symptom Scale (BSS) scores weeks 9-12. An intention-to-treat analysis of covariance evaluated treatment effects on quantitative endpoints, adjusting for age and gender. Adequate relief and change in pain score were assessed using a chi-squared test. Results: Eighty-five patients were recruited and randomised. Sample characteristics include: mean age 39.4 (SD = 14.6); 73 (86%) female; 37 (44%) IBS-D, 29 (35%) IBS-M, 18 (21%) IBS-C. The pregabalin arm had lower average pain-BSS scores weeks 9-12 (25 vs 42, P = 0.008). Compared with placebo, the overall IBS BSS severity score was lower in the pregabalin arm (26 vs 42, P = 0.009). Differences were observed for the diarrhoea-BSS and bloating-BSS scores (P = 0.049 and 0.016, respectively). No differences between groups were seen for constipation-BSS scores. Adequate relief was not different between the two arms (46% vs 36%, P = 0.35). 63% pregabalin vs 45% placebo had a change in pain score ≥30 at week 12 from baseline (P = 0.10). Post-treatment IBS-QoL scores did not differ between groups. Conclusion: This trial suggests that pregabalin may be beneficial for IBS abdominal pain, bloating and diarrhoea.