Plecanatide is a peptide drug taken as a daily pill for chronic constipation, built by mimicking a hormone the gut already makes on its own. Sold under the brand name Trulance, it belongs to a small class of GI-targeted peptide drugs that work locally in the intestine rather than circulating through the bloodstream.
What It Is
Plecanatide is a 16-amino-acid synthetic peptide designed to closely resemble uroguanylin, a natural peptide hormone produced by cells lining the small intestine that helps regulate fluid secretion and bowel movement. Because it's structurally similar to a hormone the gut already recognizes, plecanatide is classified as a guanylate cyclase-C (GC-C) receptor agonist.
What It's Approved For
The FDA approved plecanatide (Trulance, now marketed by Salix/Bausch Health after originating with Synergy Pharmaceuticals) on January 19, 2017 for chronic idiopathic constipation in adults. A second approval followed on January 25, 2018, adding irritable bowel syndrome with constipation (IBS-C) as an indication. It's taken as a once-daily oral tablet.
How It Works
Plecanatide binds and activates GC-C receptors on the surface of intestinal epithelial cells. This triggers a signaling cascade that increases secretion of chloride and bicarbonate into the intestine, which in turn pulls fluid into the gut, softening stool and promoting more regular bowel movements. Because plecanatide acts on receptors in the gut lining itself and is minimally absorbed into the bloodstream, its effects are intended to stay largely local to the digestive tract rather than producing broader systemic effects.
What the Trials Showed
In the Phase 3 program supporting the IBS-C approval, which enrolled over 1,100 adults, plecanatide was evaluated using an "Overall Responder" measure requiring at least a 30% reduction in worst abdominal pain and at least one additional complete spontaneous bowel movement in the same week, sustained for at least half of the 12-week treatment period. Reported responder rates were 21.5% for the 3 mg dose and 24.0% for the 6 mg dose, compared with 14.2% on placebo — differences the company reported as statistically significant.
Safety Considerations
The most common side effect in trials was diarrhea, reported in roughly 3% to 4% of patients on plecanatide compared with about 1% on placebo; it was also the most common reason patients stopped treatment. Overall rates of serious adverse events were low and similar between plecanatide and placebo groups. As with the related drug linaclotide, plecanatide carries a boxed warning against use in children younger than 6, based on a juvenile-animal finding of severe, sometimes fatal dehydration from fluid loss in very young animals; it is also not recommended for ages 6 through 17.
How It Compares to Linaclotide
Plecanatide shares its drug class and overall mechanism with linaclotide (Linzess), another FDA-approved GC-C agonist peptide covered elsewhere on this site, though the two differ in their exact structure, receptor-binding behavior, and some trial-reported side-effect rates. A dedicated comparison of the two is covered in this site's companion article on plecanatide versus linaclotide.
The Bottom Line
Plecanatide is a clear example of a therapeutic peptide designed by borrowing directly from the body's own chemistry: rather than targeting a disease pathway with a synthetic small molecule, it's built to resemble a hormone the gut already uses, in order to nudge the same natural signaling pathway toward more regular bowel function. As with any prescription treatment for chronic constipation or IBS-C, a doctor can help weigh plecanatide against other options based on an individual's specific symptoms and health history.