Ibsrela (Tenapanor) for Constipation
Ibsrela is FDA-approved and recommended by the AGA specifically for irritable bowel syndrome with constipation (IBS-C) in adults, not for general constipation alone. 1
Key Indication Distinction
- Tenapanor is indicated exclusively for IBS-C, which requires the presence of both recurrent abdominal pain (at least 1 day per week over 3 months) AND constipation symptoms. 1
- This is not a treatment for simple constipation without the abdominal pain component that defines IBS-C. 2
- If your patient has constipation without the IBS criteria (recurrent abdominal pain associated with bowel movements), tenapanor is not the appropriate choice. 1
Evidence for IBS-C Treatment
The AGA conditionally recommends tenapanor for patients with IBS-C based on moderate-certainty evidence. 2
Efficacy Data
- 34.1% of tenapanor patients achieved the FDA responder endpoint (≥30% reduction in abdominal pain + ≥1 additional complete spontaneous bowel movement per week for 6 of 12 weeks) versus 21.7% with placebo. 3
- Abdominal pain improved with a risk difference of 12.1% over placebo (RR 0.81; 95% CI 0.73-0.88). 2, 3
- Bowel movement frequency improved with a risk difference of 11.3% over placebo (RR 0.83; 95% CI 0.77-0.90). 2, 3
- 58.1% reported adequate symptom relief at 12 weeks versus 41.1% with placebo. 2, 3
- Tenapanor improves abdominal symptoms even in patients who don't achieve increased bowel movements, demonstrating effects on visceral hypersensitivity beyond just laxation. 4
Dosing and Administration
The FDA-approved dose is 50 mg twice daily, taken immediately before breakfast and immediately before dinner. 5, 1
- Twice-daily dosing is superior to once-daily with equivalent total doses due to pharmacodynamic effects. 5
- This is a locally acting medication with minimal systemic absorption, reducing drug-drug interactions. 2, 6
Safety Profile
Diarrhea is the primary adverse effect, occurring in 14.8-16% of patients versus 2.3-4% with placebo. 2, 3, 4
- Diarrhea led to discontinuation in 6.6% of tenapanor patients versus 1.0% with placebo. 2, 3
- Most diarrhea cases are mild to moderate; severe cases are rare. 7
- Long-term safety data (≥52 weeks) shows similar safety profile to shorter trials, with diarrhea occurring in 11.1% of long-term users. 7
- No deaths occurred in clinical trials. 2, 7
Drug Interactions
Monitor OATP2B1 substrates (e.g., enalapril) for potential reduced exposure when co-administered with tenapanor. 3
Clinical Positioning
Use tenapanor when your patient meets IBS-C diagnostic criteria (Rome IV: recurrent abdominal pain ≥1 day/week for 3 months, associated with defecation changes, plus constipation predominance). 2, 1
- The AGA positions tenapanor alongside other secretagogues (plecanatide, linaclotide) as conditional recommendations for IBS-C. 3
- For simple constipation without IBS, consider osmotic laxatives (polyethylene glycol) or stimulant laxatives (senna, bisacodyl) instead. 8
Mechanism of Action
Tenapanor inhibits intestinal NHE3 (sodium/hydrogen exchanger isoform 3), decreasing sodium and phosphate absorption, increasing luminal water secretion, and reducing visceral hypersensitivity through effects on TRPV1-mediated nociceptive signaling. 2, 3, 9