At a glance
| Product | Linzess; Constella in some markets |
|---|---|
| Target | Intestinal GC-C receptor |
| Route | Oral capsule |
| Current pediatric scope | IBS-C ≥7; functional constipation ≥2 |
| Main risk | Diarrhea and dehydration |
Overview
Linzess acts mainly within the intestinal lumen rather than requiring substantial systemic absorption. The intended outcomes are easier and more frequent bowel movements and, in IBS-C, improvement in associated abdominal symptoms. Diagnosis matters because constipation can result from obstruction, medicines, pelvic-floor problems or other diseases that a secretory agent does not correct. The October 2026 label contains broader pediatric indications than older summaries. Age thresholds differ by diagnosis, so an age-appropriate approval for functional constipation should not be mistaken for approval of every constipation-related condition in that child.
How it works
Linaclotide and its active metabolite bind guanylate cyclase-C on intestinal epithelial cells. Increased intracellular cyclic GMP stimulates chloride and bicarbonate secretion through CFTR, drawing fluid into the lumen and accelerating transit. Extracellular cyclic GMP has reduced activity of pain-sensing nerves in animal experiments. That mechanistic observation helps explain development but should be distinguished from clinical symptom outcomes in people.
Current approved populations
U.S. labeling includes IBS-C in adults and children seven or older, chronic idiopathic constipation in adults, and functional constipation in children two or older. These indication-specific ages supersede older descriptions that restricted all pediatric use to age six or above.
Supporting sources [1]
What trials measure
Randomized IBS-C studies assessed both abdominal pain and complete spontaneous bowel movements. This distinction matters: more frequent stool passage and less abdominal pain are related but separate outcomes. Pediatric approvals rely on age- and indication-specific development, not simply extrapolation from adult doses.
Diarrhea and dehydration
Diarrhea is the major adverse effect and can be severe. Abdominal pain, gas and distension also occur. The boxed warning addresses serious dehydration in children younger than two, for whom the medicine is contraindicated.
Supporting sources [1]
When the diagnosis changes the decision
Known or suspected mechanical gastrointestinal obstruction is a contraindication. A secretory bowel medicine should not be treated as a way to push through an unexplained obstructive process. Persistent or changing symptoms can require reassessment of the original diagnosis.
Supporting sources [1]
Does local action mean no systemic concerns?
Minimal absorption limits direct systemic exposure, but excessive intestinal fluid loss can still have whole-body consequences. The relevant safety question is therefore both where the peptide acts and what the resulting diarrhea or dehydration does to the patient.
Supporting sources [1]
Reading this profile
Jurisdiction: United States — FDA-approved prescription medicine; indication and formulation restrictions apply.. Molecular class: Guanylate cyclase-C agonist peptide.
This profile was written with AI-assisted research and checked against the linked sources. It has not been represented as a clinician’s review. Evidence summaries describe the cited studies and products; they do not establish that a separately purchased preparation is equivalent.
Sources & references
Follow the original material. Product labels define specific formulations and uses; trial registration describes a study and does not by itself establish benefit.
- Linzess prescribing information, revised October 2026 ↗Regulatory source · Checked 2026-10-27
- Linaclotide for irritable bowel syndrome with constipation: a 26-week, randomized, double-blind, placebo-controlled trial to evaluate efficacy and safety. ↗Original research · Checked 2026-10-27