Drug Survival of Drugs Recommended for Irritable Bowel Syndrome: A Retrospective Observational Study

There is limited data on how drugs prescribed for functional bowel disorders are re-prescribed in clinical practice. This study aimed to investigate drug survival rates of different irritable bowel syndrome (IBS) treatments among patients referred to a gastroenterologist.

A retrospective observational study was conducted by reviewing medical charts of patients aged 18-50 years, diagnosed with IBS or an unspecified functional intestinal disorder between 2010 and 2018. Drug survival rates for various treatment categories were analyzed using Kaplan-Meier curves and log-rank tests.

A total of 1528 treatment attempts were recorded in 529 patients, with 883 classified as treatment-naïve. Simethicones demonstrated significantly higher drug survival compared to bulking agents (p = 0.009). Tricyclic antidepressants (TCA), loperamide, and simethicones all showed superior survival rates compared to osmotic laxatives (p = 0.039, p = 0.025 and p = 0.003, respectively). Additionally, loperamide and simethicones had better survival rates than antispasmodics (p = 0.046 and p = 0.012, respectively). At 60 months, the cumulative drug survival rate was highest for TCA (11%), followed by loperamide (10%) and simethicones (7%), all significantly outperforming bulking agents (1%) (p = 0.002 for TCA vs. bulking agents, p = 0.002 for loperamide vs. bulking agents, and p = 0.006 for simethicones vs. bulking agents). For all treatment-naïve attempts, the cumulative drug survival at 60 months was 6%.

The overall 60-month drug survival for treatments prescribed in IBS is relatively low, suggesting that the effectiveness of current therapies remains limited. Among the medications studied, simethicone and TCAs demonstrated the best drug survival rates.