Gastrointestinal Peptides

Linaclotide

Commonly used for

Constipation ReliefIBS-CMetabolic Health

What is it?

Linaclotide is a 14-amino acid synthetic peptide that activates guanylate cyclase-C receptors within the intestinal epithelium. It was the first GC-C agonist developed for chronic constipation disorders. Unlike plecanatide, linaclotide is structurally derived from the bacterial heat-stable enterotoxin peptide but is modified for therapeutic use.

Brand names: Linzess® (US), Constella® (Europe)

Mechanism of action: Guanylate cyclase-C receptor agonist; Increases intracellular cGMP; Activates CFTR chloride channels; Increases intestinal fluid secretion; Accelerates gastrointestinal transit; Reduces visceral pain through extracellular cGMP signaling

What do people use it for?

Approved indications: Irritable Bowel Syndrome with Constipation (IBS-C); Chronic Idiopathic Constipation (CIC); Functional constipation in selected pediatric populations (age-specific approvals)

Proposed indications: Opioid-induced constipation; Functional bowel disorders; Chronic abdominal pain; Pelvic floor dysfunction (adjunct); Radiation-induced constipation

How is it used? / Dosing

Administration: Oral capsule, taken on an empty stomach at least 30 minutes before the first meal of the day — Once daily

How does it compare?

Compare with:

How well does it work? / Evidence

✓ Well-established

Evidence rating: Grade A — Extensively studied with numerous randomized controlled trials and long-term safety data.

Landmark trials: Multiple Phase III trials — Consistently demonstrated increased complete spontaneous bowel movements, reduced abdominal pain, improved quality of life in IBS-C, and sustained efficacy with long-term treatment.

Safety & side effects

Common side effects: Diarrhea, Abdominal pain, Flatulence, Abdominal distension, Urgency

Serious risks: Severe diarrhea leading to dehydration; Pediatric toxicity (boxed warning)

Drug interactions: No clinically meaningful systemic drug interactions are expected because of negligible systemic absorption.

Monitoring: Stool frequency, Stool consistency, Symptom improvement, Hydration status, Diarrhea severity

Legal & regulatory status

Legal status: Prescription required. This is an FDA-approved medication available only through a licensed prescriber — dosing is determined by your prescriber based on your medical history and is not provided here.

Regulatory status: FDA Approved • EMA Approved

Who should avoid it?

Contraindications: Known or suspected mechanical gastrointestinal obstruction; Children under 2 years of age (boxed warning due to dehydration risk); Hypersensitivity

Pregnancy & breastfeeding: Limited human data. Given minimal systemic absorption, fetal exposure is expected to be low, but use should be based on clinical need.

Research & references

Chey WD, et al. (2012). Linaclotide for Irritable Bowel Syndrome with Constipation. New England Journal of Medicine, 366(7), 617–624. https://doi.org/10.1056/NEJMoa1111094 Lembo AJ, et al. (2011). Two Randomized Trials of Linaclotide for Chronic Constipation. New England Journal of Medicine, 365(6), 527–536. https://doi.org/10.1056/NEJMoa1010863