As I reviewed recently published research studies, I was excited to see an investigation of another potential prescription medication for constipation predominant IBS. I had just written about prucalopride, a 5-HT4 medication. This new study looked at a medication called renzapride, so I did a little poking around. The interesting thing about renzapride is that it was designed to target both the 5-HT4 and the 5-HT3 receptors so as to treat both IBS-C and IBS-A, in which symptoms alternate between constipation and diarrhea. Targeting of the 5-HT4 receptors is thought to increase motility and thus increase the number of bowel movements. In terms of the 5-HT3 receptors, the medication sought to reduce their activity, resulting in fewer symptoms of diarrhea and abdominal pain.

The study that caught my eye, “Clinical trial: renzapride therapy for constipation-predominant irritable bowel syndrome – multicentre, randomized, placebo-controlled, double-blind study in primary healthcare setting” found that a 4 mg dose of renzapride increased the frequency of bowel movements in IBS-C patients. There was also an indication that the female study participants who received the 4 mg dosage experienced a decrease in abdominal pain.

Now for the bad news: Alizyme, the manufacturer of renzapride, apparently announced this past April that they are discontinuing any further investment into research and development for this drug. The reason given was that although the drug appeared to be well-tolerated, without significant side effects, there was no strong evidence of its effectiveness. This would appear to put renzapride at a dead end. Bummer!

Hopefully, the search for improved treatment for IBS will continue on. In the meantime, if you would like more information about the current available treatment options for IBS-C, see my article, “Medication for Constipation Predominant IBS”.

_Source:

George, A., Meyers, N. & Hickling, R. “Clinical trial: renzapride therapy for constipation-predominant irritable bowel syndrome – multicentre, randomized, placebo-controlled, double-blind study in primary healthcare setting” Alimentary Pharmacology & Therapeutics 2008 27:830-837.