Over the past decade, new therapies for irritable bowel syndrome with constipation (IBS-C) have emerged, but treatment options remain limited for patients unresponsive to secretagogues. Tenapanor, a sodium/hydrogen exchanger 3 inhibitor, offers a novel mechanism of action by reducing sodium absorption in the intestines, leading to increased intestinal fluid and softer stools. Initially developed for hyperphosphatemia, tenapanor demonstrated GI benefits and minimal systemic availability. Preclinical studies showed tenapanor reduced intestinal permeability and visceral hypersensitivity. Early-phase clinical trials confirmed its safety, tolerability, and favorable pharmacodynamics, with mild GI-related adverse events.

Tenapanor’s efficacy was further validated in Phase II and III trials, where it significantly improved both bowel function and abdominal symptoms in patients with IBS-C. The drug met FDA responder endpoints, improved quality of life scores, and was well tolerated aside from diarrhea being the most frequent side effect. Approved by the FDA in 2019, tenapanor is now a recommended option for patients with IBS-C who are unresponsive to first-line treatments like fiber or polyethylene glycol. Unlike serotonin agonists, tenapanor has no cardiovascular restrictions and presents a distinct, safe alternative. However, treatment decisions will likely continue to be shaped by cost and comparative safety data across available pharmacologic agents.

Reference: Herekar A, Shimoga D, Jehangir A, et al. Tenapanor in the Treatment of Irritable Bowel Syndrome with Constipation: Discovery, Efficacy, and Role in Management. Clin Exp Gastroenterol. 2023 Jun 7;16:79-85. doi: 10.2147/CEG.S384251. PMID: 37309470; PMCID: PMC10257918.

This nationwide, population-based study used data from the National GI Survey to evaluate abdominal pain characteristics across irritable bowel syndrome (IBS) subtypes using the validated GI-PROMIS instrument. Of the 71,812 survey participants, 1,158 met modified Rome III criteria for IBS and reported abdominal pain within the past 7 days. These participants were stratified into IBS with diarrhea (IBS-D), IBS with constipation (IBS-C), and IBS with mixed bowel habits (IBS-M) groups. Compared to IBS-D, individuals with IBS-C reported significantly more bothersome, frequent, and interfering abdominal pain. IBS-C and IBS-M also showed more diffuse pain patterns and involvement of a greater number of abdominal regions. IBS-C had the highest composite GI-PROMIS scores, indicating greater pain burden.

The study highlights that abdominal pain manifests differently across IBS subtypes, with patients with IBS-C experiencing the most severe and diffuse symptoms. These differences may reflect distinct underlying mechanisms, including variations in visceral hypersensitivity and neural pain processing. The findings suggest that abdominal and bowel symptoms differ not only in frequency but in qualitative experience across subtypes, potentially supporting a move toward subtype-specific management strategies. Limitations included lack of medication and mood disorder assessments, but strengths included use of a validated, symptom-specific tool and a nationally representative cohort.

Reference: Shah ED, Almario CV, Spiegel BM, et al. Presentation and Characteristics of Abdominal Pain Vary by Irritable Bowel Syndrome Subtype: Results of a Nationwide Population-Based Study. Am J Gastroenterol. 2020 Feb;115(2):294-301. doi: 10.14309/ajg.0000000000000502. PMID: 31913193; PMCID: PMC7469977.

Chronic idiopathic constipation (CIC) and irritable bowel syndrome with constipation (IBS-C) are complex conditions involving a range of abdominal and bowel symptoms, including bloating, straining, abdominal pain, and hard stools. Effective symptom reporting is essential for diagnosis and individualized treatment, yet many patients delay seeking care due to embarrassment, dissatisfaction with prior healthcare encounters, or inadequate communication with providers. A strong clinician–patient relationship is critical to overcoming these barriers, enabling more accurate symptom reporting, improving health-related quality of life, and enhancing satisfaction with care. Patient-centered communication, shared understanding of symptom experiences, and education on symptom terminology are key components of successful long-term management.

Monitoring treatment response in CIC and IBS-C is equally important. Various patient-reported symptom scales—ranging from global assessments to detailed individual symptom tracking—can help clinicians evaluate treatment efficacy and refine care strategies. While global assessments offer a broad view of symptom burden, individualized symptom tools provide granular insights that guide more tailored treatment decisions. Including patients in discussions about their most bothersome symptoms, treatment expectations, and long-term care goals can improve adherence, outcomes, and overall satisfaction.

Reference: Kassebaum-Ladewski A, Poppers DM, Brenner DM. Effective Communication Strategies and Tools for Improving Treatment Outcomes in Patients With Chronic Idiopathic Constipation and Irritable Bowel Syndrome With Constipation. Am J Gastroenterol. 2022 Apr 1;117(4S):S14-S20. doi: 10.14309/ajg.0000000000001686. PMID: 35354771.