Linaclotide
Guanylate cyclase-C agonist
Also Linzess, Constella, MD-1100, MM-416775
- Evidence
- AStrong human evidence
- FDA status
- FDA approvedas of 2026-10-26
- Route
- Oral
- Studies cited
- 1 human0 animal or cell
A prescription capsule for constipation and irritable bowel syndrome. Several large controlled trials show it works.
Sold for
Linaclotide is a prescription constipation drug; the only hype around it is marketing to IBS-C patients, and it is not sold in the gray peptide market.
Studies say
Multiple large randomized placebo-controlled trials met their FDA-set endpoints, which is why it grades A.
Why grade A. The adult IBS-C approval rests on two phase 3 randomized placebo-controlled trials with about 800 patients each (1,604 in total, per the label); the cited 2012 paper reports the 26-week trial of 804 patients. Two further trials support chronic constipation, and the pediatric extensions rest on additional randomized trials. Head-to-head comparisons with other secretagogues such as plecanatide are missing. 12
FDA. Approved. Linaclotide (Linzess) was approved in 2012 for irritable bowel syndrome with constipation and chronic idiopathic constipation in adults. The current label also covers IBS with constipation in children 7 and older and functional constipation in children 2 and older, the latter extended from age 6 in May 2026. It is contraindicated in children under 2. 2
Written from 2 cited sources. Fact-checked 2026-10-27: 15 claims checked, 5 corrected. Last refreshed 2026-10-27. Not physician reviewed.
What this means for you
- What people take it for
- Constipation and irritable bowel syndrome
- Can a US doctor prescribe it?
- Yes, FDA approved for constipation and irritable bowel syndrome with constipation.
- Properly tested in people?
- Yes, in large controlled trials of about 800 people each.
Evidence checklist
- Randomised controlled trial Two phase 3 placebo-controlled trialsyes
- Human study over 100 people 1,604 patients across the IBS-C trialsyes
- More than one research group Trials mainly from the sponsorsno information
- Clinical outcomes, not surrogate markers Bowel movements and abdominal symptomsyes
- Human safety data beyond case reports Large trials, boxed warning under age 2yes
Drawn from the cited studies below. A dash means the sources give no information.
What it is
Linaclotide is a 14-amino-acid peptide taken as a capsule. It is almost not absorbed into the blood at all; it acts on the surface of the intestine and is broken down in the gut. It was developed by Ironwood Pharmaceuticals and is sold with AbbVie as Linzess in the US. 2
The approved uses are irritable bowel syndrome with constipation (IBS-C) in adults and children 7 and older, chronic idiopathic constipation in adults, and functional constipation in children aged 2 and older. The functional constipation approval came in stages: 6 to 17 in 2023, then 2 and up in May 2026. 2
How it works
Linaclotide is a guanylate cyclase-C agonist. It binds that receptor on the intestinal lining, which raises cyclic GMP inside and around the cells. The result is more chloride and bicarbonate secreted into the gut, more water following it, and faster transit. In animal studies, the extra cyclic GMP also quiets pain-sensing nerves in the gut wall, which is the proposed explanation for the drop in abdominal pain seen in IBS-C trials. 2
What human research shows
Two phase 3 trials randomized a combined 1,604 adults with IBS-C to linaclotide or placebo, one for 12 weeks plus a 4-week withdrawal period and one for 26 weeks. In the 26-week trial, reported by Chey and colleagues, 804 patients were evaluated. On the FDA's combined endpoint (at least 30 percent less abdominal pain and at least one more complete spontaneous bowel movement per week, both in at least 6 of the first 12 weeks), 33.7 percent of linaclotide patients responded versus 13.9 percent on placebo. Differences from placebo held through 26 weeks. 12
The chronic constipation and pediatric trials summarized in the label show the same pattern: more complete spontaneous bowel movements per week than placebo, with diarrhea as the main cost. 2
| Study | Model | Finding |
|---|---|---|
| Chey 2012, 26-week phase 3 IBS-C trial | Humans, n=804, randomized double-blind placebo-controlled, 26 weeks | 33.7% of linaclotide patients met the FDA composite responder endpoint versus 13.9% on placebo; diarrhea led 4.5% to stop. 1 |
| Linzess prescribing information | FDA label including adult chronic constipation and pediatric functional constipation trials | More complete spontaneous bowel movements than placebo across indications; boxed warning against use under age 2. 2 |
Safety
Diarrhea is the dominant side effect, affecting 20 percent of adults in the IBS-C trials (3 percent on placebo) and causing 5 percent to stop. Abdominal pain, gas, and bloating are also reported. The label carries a boxed warning: linaclotide is contraindicated in children under 2 because young juvenile mice died of dehydration in toxicology studies. 12
Because almost none of the drug reaches the bloodstream, systemic side effects and drug interactions are minimal. Pregnancy data in humans are limited. 2
Questions for your clinician
- How does linaclotide compare with other constipation drugs for my symptoms?
- What can I do if diarrhea develops?
- Why is it not given to very young children?
Questions people ask
Who is linaclotide prescribed to?
IBS with constipation in adults and children 7 and older, chronic idiopathic constipation in adults, and functional constipation in children aged 2 and older. 2
How is it different from a laxative?
Laxatives such as polyethylene glycol pull water into the stool osmotically. Linaclotide switches on a receptor on the gut lining that makes the intestine secrete fluid itself and, in IBS-C trials, also reduced abdominal pain, which laxatives generally do not. 12
Why is there a boxed warning for young children?
Juvenile mice died of dehydration in preclinical studies, so the FDA contraindicated the drug in children under 2. Studies in older children supported approval from age 2. 2
How fast does it work?
In the 26-week IBS-C trial, abdominal pain and bowel symptoms improved more than on placebo over the first 12 weeks, and the differences were maintained through 26 weeks. 1
Citations
- Chey 2012, Am J Gastroenterol: linaclotide for irritable bowel syndrome with constipation, 26-week randomized placebo-controlled trial doi.org
- AbbVie: Linzess US prescribing information, revised 2026 rxabbvie.com