Asimadoline for IBS

Pharmacist walking through pharmacy

Asimadoline is a medication currently undergoing clinical trials to assess its effectiveness as a treatment for IBS. Asimadoline has also been tested as a potential treatment for functional dyspepsia.

How Asimadoline Works:

Asimadoline is a medication that is taken orally. It is classified as a kappa-opioid agonist. Kappa-opioid receptors are found throughout the central and peripheral nervous systems and are thought to be involved with visceral sensitivity.

Asimadoline was designed to have low permeability through the blood/brain barrier, thus acting on nerve endings within the peripheral nervous system to reduce pain. This lack of effect on the central nervous system results in fewer unwanted side effects.

Asimadoline for IBS:

Several studies have been conducted to evaluate the effectiveness of asimadoline in easing IBS symptoms. Although results have been mixed, there is evidence that asimadoline is superior to placebo in reducing pain and discomfort associated with irritable bowel syndrome alternating type (IBS-A) and diarrhea-predominant IBS (IBS-D). There has been no evidence to date of asimadoline being effective in reducing pain in patients who suffer from constipation predominant IBS (IBS-C).

Asimadoline Side Effects:

In studies to date, asimadoline appears to be well-tolerated without any significant side effects.

When Will Asimadoline Be Available:

Asimadoline is currently undergoing Phase III clinical trials so as to obtain FDA approval. But it is not clear when -- or if -- the FDA will approve the drug.


Camilleri, M. "Asimadoline, a k-Opioid Agonist, and Visceral Sensation " Neurogastroenterology & Motility 2008 20:971-979.

Maneerattanaporn, M., Chang, L., & Chey, W. "Emerging Pharmacological Therapies for the Irritable Bowel Syndrome" Gastroenterology Clinics of North America 2011 40:22-243.

Mangel, A. et. al. “Clinical trial: asimadoline in the treatment of patients with irritable bowel syndrome” Alimentary Pharmacology & Therapeutics 2008 28:239-249.

"Tioga Pharmaceuticals Begins Phase 3 Trial of Asimadoline in Irritable Bowel Syndrome" Tioga Pharmaceuticals, Inc. Press release. June 3, 2010.

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