A Multicenter, Prospective Real-World Study of Simethicone–Activated Charcoal in Patients With Persistent Dyspeptic Symptoms Despite Acid Suppression (SIMAC Study)

Abstract

Background

Persistent gas-predominant dyspeptic symptoms affect many patients despite adequate proton pump inhibitor (PPI) therapy, reflecting mechanisms beyond acid secretion. We evaluated the real-world effectiveness and safety of simethicone (80 mg) plus activated charcoal (250 mg) in adults with persistent symptoms despite prior PPI therapy.

Methods

In this prospective, multicenter observational study across nine Indian sites, adults with persistent gas-related symptoms despite ≥ 2 weeks of standard-dose PPI therapy received the combination thrice daily for 28 days. Severity across 11 gastrointestinal domains was assessed using a modified Visual Analog Severity scale at baseline, Day-14, and 28. The primary outcome was change in symptom severity from baseline to Day 28, analyzed using Friedman testing with Bonferroni-adjusted Wilcoxon post hoc comparisons. A global symptom score (mean of all 11 domains) was used for exploratory subgroup analyses; secondary outcomes included adherence and safety.

Results

All 183 participants completed follow-up, with significant reductions across all 11 symptoms (all p < 0.001). Belching decreased from 46.3 ± 26.4 to 10.9 ± 19.5, epigastric burning from 48.1 ± 27.3 to 10.7 ± 17.9, and bloating from 44.2 ± 29.1 to 12.9 ± 18.6. Improvements were evident by Day-14 and sustained to Day-28. The median global symptom score reduction was 25.0 units (95% CI: 22.7–27.3), with consistent improvement across demographic and clinical subgroups. Full adherence was 87.1% at Day 14 and 83.6% at Day 28, with no serious clinical events.

Conclusion

In patients with persistent gas-predominant dyspepsia despite PPI therapy, simethicone–activated charcoal was associated with significant short-term symptomatic improvement. Controlled trials are warranted to confirm treatment effect.