Table 1.
Summary of Current and Most Promising Novel Therapies for IBS
| Drug | Drug Class | Pharmacodynamic | Clinical Efficacy | Adverse effects |
|---|---|---|---|---|
| Antispasmodics, peppermint oil | Antispasmodics, peppermint oil | Muscle relaxant | Episodic pain; older, relatively small trials | - |
| Prucalopride | 5-HT4 receptor agonist | Accelerate colon transit | Extensive clinical trial efficacy for CC, not for IBS | Concerns about 5-HT4 cardiac effects appear unfounded based on dose difference to stimulate IKr |
| Velusetrag | 5-HT4 receptor agonist | Single phase II CC study shows efficacy | ||
| Naronapride | 5-HT4 receptor agonist | Single phase II CC study shows efficacy | ||
| Alosetron | 5-HT3 receptor antagonist | Delay colon transit, reduce visceral sensation | Extensive clinical trial efficacy for IBS-D | Significant constipation, class-related ischemic colitis |
| Ramosetron | 5-HT3 receptor antagonist | 2 trials clinical efficacy for IBS-D | ||
| Dexloxiglumide | CCK1 receptor antagonist | Delay asc. colon transit | Inconsistent efficacy in trials | - |
| Lubiprostone | Cl-channel opener | Accelerate SB and colon transit | Extensive clinical trial efficacy for CC, IBS-C | Nausea in ~25% |
| Linaclotide | Guanylate cyclase C receptor agonist | Accelerate colon transit | Extensive clinical trial efficacy for CC, IBS-C | Diarrhea |
| Colesevelam | Bile acid binder | Slows colon transit based on BA synthesis rate | No clinical trials | - |
| Na cromoglycate | Mast cell stabilizer | Reduced mast cells | Weak clinical trial efficacy | - |
| Ketotifen | Mast cell stabilizer, histamine H1 receptor antagonist | Unclear, ? reduced sensation | Weak clinical trial efficacy | Central effects e.g. fatigue |
| Mesalazine | 5-ASA agent | Reduced inflammation | Weak clinical trial efficacy | - |
| Pregabalin | GABA; α2δ ligand | Reduced pain in animal and human models of IBS | No completed clinical trials | Central effects |
| Tricyclics | Tricyclics | Few small positive trials; Meta-analysis unconvincing | Central effects; constipation; anti-cholinergic effects | |
| SSRI/SNRI | SSRI/SNRI | Central effects; diarrhea | ||
| Dextofisopam | Benzodiazepine | Unclear | Weak clinical trial efficacy | Central effects? |
| Asimadoline | K opioid receptor agonist | Reduced pain in models | Weak clinical trial efficacy | - |
| Probiotics | Unclear | Bifidobacteria, combined probiotics beneficial | - | |
| Rifaximin | Unabsorbed antibiotic | Adequate relief of IBS and bloating | Extensive clinical trial efficacy for IBS-non-C | Efficacy persists for 10 weeks after stopping Rx |