Rethinking IBS Management: The Shift Toward Precision Care, With Ali Rezaie, MD

Irritable bowel syndrome (IBS) remains one of the most common but complex disorders in gastroenterology, historically characterized by a symptom-based diagnosis and broad treatment strategies. However, growing insight into its diverse underlying mechanisms has prompted a shift in how clinicians approach management.

In an interview with HCPLive, Ali Rezaie, MD, highlighted how instead of relying solely on empiric, symptom-driven care, today’s paradigm increasingly emphasizes careful evaluation, patient-specific factors, and targeted therapies that reflect a deeper understanding of IBS as a heterogeneous condition rather than a single disease entity.

Check out part 1 of the interview with Rezaie here.

Historically, he said clinicians focused on dominant symptoms rather than root causes. Patients presenting with diarrhea were typically prescribed antidiarrheals, while those with constipation received laxatives. While this approach offered some degree of symptom relief, it often failed to address the heterogeneity of the disorder.

As Rezaie explained, IBS is not a single disease entity but rather a collection of conditions grouped under a broad diagnostic umbrella defined by abdominal pain and altered bowel habits.

Today, management begins with a thorough clinical evaluation, including detailed history-taking and physical examination to exclude alarm features and rule out alternative diagnoses such as malignancy, inflammatory bowel disease, or structural abnormalities. This step remains critical to ensuring appropriate treatment and avoiding missed diagnoses with more serious prognoses.

Lifestyle and dietary assessment also play a central role in modern IBS care. Clinicians increasingly emphasize the importance of dietary modification and “cleaner” eating patterns, which can provide meaningful symptom improvement for some patients. However, Rezaie noted that lifestyle interventions alone are often insufficient for many patients.

“The reality is that the majority of the patients, just by dietary modification and lifestyle changes, won't see that much improvement to a point where they're considered tolerable,” he explained. “So as the next step, we reach for pharmacotherapy.”

Multiple US Food and Drug Administration-approved therapies are now available for IBS with constipation (IBS-C) and IBS with diarrhea (IBS-D), addressing mechanisms such as gut motility, fluid secretion, and, in some cases, the gut microbiome.

Beyond approved therapies, clinicians continue to use a range of guideline-supported agents, including antidepressants, antispasmodics, bile acid sequestrants, and μ-opioid receptor agonists, though Rezaie noted many of these primarily target symptoms rather than underlying disease drivers. Increasingly, the field is moving toward identifying distinct IBS subtypes and matching therapies accordingly, informed by both clinical presentation and, when available, diagnostic testing.

According to Rezaie, this shift represents a marked departure from the “one-size-fits-all” strategies of the past.

“This is a dramatic shift from 20, 30, years ago, when we would empirically treat patients and mostly just target symptoms,” he explained. “So if you have diarrhea, this is your constipating agent. Or if you have constipation, here's your laxative. That has changed.”

By recognizing IBS as a spectrum of disorders with diverse pathophysiologic mechanisms, Rezaie says clinicians are better positioned to deliver more precise, effective, and individualized care.

Editors’ note: Rezaie reports relevant disclosures with Bausch Health, Ardelyx, and others.

References

1. Mehravar, S., Yeo, Y.H., Pimentel, M. et al. Association of pharmacotherapy with all-cause mortality among patients with irritable bowel syndrome. Commun Med 6, 176 (2026). https://doi.org/10.1038/s43856-026-01498-6

2. Cedars-Sinai Medical Center. Some common IBS treatments linked to higher risk of death. EurekAlert! April 8, 2026. Accessed April 13, 2026. https://www.eurekalert.org/news-releases/1122913