Choosing Effective Pharmacologic and Nonpharmacologic Approaches to Irritable Bowel Syndrome Treatment

Noting that the “complicated pathophysiology” of irritable bowel syndrome (IBS) and the lack of effective drugs that satisfactorily treat the symptoms of IBS means there is high demand for new therapeutic agents for this condition, the authors of “Metabolic and Toxicological Considerations for the Latest Drugs Used to Treat Irritable Bowel Syndrome,” published in Expert Opinion on Drug Metabolism & Toxicology, conducted a systematic review of the literature to provide an update “on new clinically introduced drugs for IBS and their dynamics and kinetics data.”

Among their findings:

• Some drugs, such as ramosetron (a 5-HT3 antagonist) and pexacerfont (a CRF1 receptor antagonist), have “shown some benefits in diarrhea-predominant IBS (D-IBS”
• Prucalopride and mosapride (5-HT4 agonists) with prokinetic effect “were found useful in constipation-predominant IBS (C-IBS)”
• Dexloxiglumide, lubiprostone and linaclotide “have shown beneficial effects in C-IBS patients”
• Melatonin regulates GI tract motility and asimadoline, gabapentin and pregabalin “show reduction of pain threshold and visceral hypersensitivity”
• Glucagon-like peptide analog, calcium-channel blockers, and neurokinin receptor antagonists have shown some benefit in treating pain associated with IBS

The authors wrote that “More time is required to indicate both efficacy and safety in long-term treatment due to multifactorial pathophysiology, variations in individual responses and insufficient assessment methods, which limit the right decision-making process about the efficacy and tolerability of these new drugs.”

While researchers continue to look for new and novel pharmacologic therapies for IBS, others have focused on nonpharmacologic approaches such as hypnotherapy and cognitive behavioral therapy (CBT). One recent study by Labus and colleagues looked at whether “a short course of group psycho-educational treatment consisting of combined CBT and basic relaxation techniques result in sustained, clinically relevant improvement of IBS symptom severity and health-related quality of life.” The researchers also attempted to identify “the factors that predict a positive outcome (moderators), and the factors that mediate the positive outcomes of the intervention.”

Although the authors reported that “patients who participated in the psycho-education classes improved on all key measures by the end of the intervention, and demonstrated lower overall symptom severity ratings than those in the control group,” it was unclear which specific aspect of therapy was most responsible for producing these outcomes.

This was underscored in a recent commentary in Alimentary Pharmacology and Therapeutics. The author noted that although the study of psycho-educational therapy for IBS was “the first attempt to subject what they describe as a psycho-educational intervention to the rigours of modern clinical research methodology,” and supported previous research that found “positive physician-patient interaction” and patient education improved symptoms and reduced physician visits, the study “cannot tell us is why their approach worked and, specifically, which of the elements of the programme was most beneficial.”

Pragmatically, the author wrote that “determining the operative element(s) of the strategy employed by Labus and colleagues is of practical, as well as academic, interest; this information will be critical when one attempts to find support for such a programme, be it from a hospital, an academic institution or a payor.”