Ibsrela® (tenapanor) is now available for the treatment of irritable bowel syndrome with constipation (IBS-C) in adults.

Ibsrela is a locally-acting inhibitor of the sodium/hydrogen exchanger 3 (NHE3), an antiporter expressed on the apical surface of the small intestine and colon primarily responsible for the absorption of dietary sodium. By inhibiting NHE3, Ibsrela reduces absorption of sodium from the small intestine and colon, resulting in an increase in water secretion into the intestinal lumen, which accelerates intestinal transit time and results in a softer stool consistency. 

The approval was based on 2 placebo-controlled, randomized, multicenter phase 3 trials (ClinicalTrials.gov Identifier: Trial 1 [NCT02686138], Trial 2 [NCT02621892]), which evaluated the efficacy and safety of Ibsrela in over 1200 adults with IBS-C. Ibsrela was administered immediately prior to the first meal of the day and immediately before dinner. The trial designs were identical through the first 12 weeks of treatment, and thereafter differed in that Trial 1 continued for an additional 14 weeks of treatment, whereas Trial 2 included a 4-week randomized withdrawal period.

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Findings from both trials showed that treatment with Ibsrela met the primary endpoint with a greater proportion of overall responders compared with placebo. Responders were defined as a patient achieving both the stool frequency and abdominal pain intensity responder criteria in the same week for at least 6 of the first 12 weeks of treatment.

Moreover, improvements from baseline in average weekly bowel movements, abdominal pain, bloating and other abdominal symptoms were observed by week 1, with improvement maintained through the end of treatment in both trials. In Trial 2, patients in the Ibsrela treatment arm also reported a 41% improvement in quality of life score from baseline to end of treatment.

As for safety, Ibsrela carries a Boxed Warning associated with the risk of serious dehydration in pediatric patients; it is contraindicated for use in patients less than 6 years of age and should be avoided in patients 6 to 12 years of age. The safety and efficacy of Ibsrela have not been established in patients less than 18 years of age.

The most common adverse reactions (incidence at least 2%) reported for Ibsrela were diarrhea, abdominal distension, flatulence, and dizziness. Treatment should be suspended if severe diarrhea occurs.

Ibsrela is available as 50mg tablets in 60-count bottles.


  1. Ardelyx announces US launch of Ibsrela®, a new first-in-class treatment for IBS-C in adults. News release. Ardelyx. Accessed April 4, 2022. https://www.prnewswire.com/news-releases/ardelyx-announces-us-launch-of-ibsrela-a-new-first-in-class-treatment-for-ibs-c-in-adults-301516463.html
  2. Ibsrela. Package insert. Ardelyx; 2022. Accessed April 4, 2022. https://www.accessdata.fda.gov/drugsatfda_docs/label/2021/211801s003lbl.pdf

This article originally appeared on MPR