What the label lists and what reports show
Tenapanor side effects
Tenapanor's FDA label: “Most common adverse reaction in the combined clinical trials was diarrhea, reported by 43-53% of patients ( 6 ).” FAERS holds 3,543 reports naming it through July 30, 2026; the reaction reported most often, leaving out the conditions it is used for, product-use terms and outcomes, is diarrhoea (1,240 reports).
- No generic listed
Check it at the source: the tenapanor FDA label on DailyMed (effective June 27, 2025, Ardelyx, Inc.); the FDA FAERS public dashboard.
What does the patient leaflet say about side effects?
From the patient leaflet: What are the possible side effects of IBSRELA?IBSRELA can cause serious side effects, including: See " What is the most important information I should know about IBSRELA? " Diarrhea is the most common side effect of IBSRELA, and it can sometimes be severe. Stop taking IBSRELA and call your doctor if you develop severe diarrhea. The other most common side effects of IBSRELA include: swelling, or a feeling of fullness or pressure in your abdomen (distension). gas (flatulence). dizziness. These are not all the possible side effects of IBSRELA. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088. You may also report side effects to www.fda.gov/medwatch.
Source: FDA drug label (IBSRELA), Ardelyx, Inc., effective May 28, 2025 (SPL set 2102da5f-a1a0-4ac7-a1f6-38698cf7273a), via openFDA; the full label on DailyMed
What does the label list?
From the label: adverse reactionsMost common adverse reaction in the combined clinical trials was diarrhea, reported by 43-53% of patients ( 6 ).
Table 1: Most Common Adverse Reactions Reported in at least 2% of patients in IBSRELA-treated patients and at an incidence greater than placebo in Patients with IBS-C in Trial 1 (26 Weeks)
This table is printed in the IBSRELA label published by Ardelyx, Inc. of May 28, 2025; the label quoted above does not print one.
| Adverse Reactions | IBSRELA N=293 % | Placebo N=300 % |
|---|---|---|
| Diarrhea | 16 | 4 |
| Abdominal Distension | 3 | <1 |
| Flatulence | 3 | 1 |
| Dizziness | 2 | <1 |
Rows and numbers as the label prints them, under its own column headings (the first rows of a longer table where it runs on). A reaction in a trial table is not necessarily caused by the medicine, and trials differ from everyday use.
From the label: adverse reactions, continuedMost common adverse reaction in the combined clinical trials was diarrhea, reported by 43-53% of patients ( 6 ). To report SUSPECTED ADVERSE REACTIONS, contact Ardelyx at 1-844-974-6924 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. 6.1 Clinical Trial Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared with rates in the clinical trials of another drug and may not reflect the rates observed in practice. The safety data described below reflect data from 754 adults with CKD on dialysis taking XPHOZAH in clinical trials as monotherapy and in combination with phosphate binders. Among the 754 patients, 258 patients were exposed to tenapanor for at least 26 weeks and 75 were exposed to tenapanor for at least one year. [see Clinical Studies (14) ]. Most Common Adverse Reaction Diarrhea, which occurred in 43-53% of patients, was the only adverse reaction reported in at least 5% of XPHOZAH-treated patients with CKD on dialysis across trials. The majority of diarrhea events in the XPHOZAH-treated patients were reported to be mild-to-moderate in severity and resolved over time, or with dose reduction. Diarrhea was typically reported soon after initiation but could occur at any time during treatment with XPHOZAH. …
Source: FDA drug label, Ardelyx, Inc., effective June 27, 2025 (SPL set c57e279c-0f1b-4238-81b7-4e0dc0cc60c5), via openFDA; the full label on DailyMed
What do FAERS reports show?
3,543 reports list tenapanor among the medicines taken, each a report of something that happened, not proof the medicine caused it; 104 are coded as a death and 558 as a hospital stay. Counts follow how widely a medicine is used and watched, and they are not a measure of how risky it is. Of the 13 reactions below, 5 are named by the same term (in US spelling) in the label's adverse reactions, warnings or patient leaflet; a reaction the label does not name may still be there under another word, and a report does not show that the medicine caused it.
Reports received each year
The 25 most reported reactions
Source: FDA Adverse Event Reporting System (FAERS) via openFDA, reports through July 30, 2026; reactions as MedDRA preferred terms
What next?
- Tenapanor: the full record
- label, generics, price, shortages, recalls
- Report a side effect to the FDA
- MedWatch
- Side effects hub
- the most reported medicines and reactions