Linaclotide
Linaclotide (Linzess)
Linaclotide is a minimally absorbed, 14-amino acid peptide agonist of guanylate cyclase-C (GC-C) receptors on intestinal epithelial cells, FDA-approved for the treatment of irritable bowel syndrome with constipation (IBS-C) and chronic idiopathic constipation (CIC) in adults. It works locally in the gastrointestinal tract to accelerate intestinal transit and reduce visceral pain. It is marketed under the brand name Linzess and is available only by prescription.
Mechanism of Action
Linaclotide binds and activates guanylate cyclase-C receptors on the luminal surface of intestinal epithelial cells, stimulating production of cyclic GMP (cGMP). Intracellular cGMP activates the cystic fibrosis transmembrane conductance regulator (CFTR), increasing secretion of chloride and bicarbonate into the intestinal lumen, which draws water in and accelerates colonic transit. Extracellular cGMP also reduces activity of pain-sensing submucosal afferent neurons, contributing to visceral analgesic effects in IBS-C.
Evidence by Health Goal(13 goals)
Dosing Protocols
At least 30 minutes before the first meal of the day, on an empty stomach
Capsules should be swallowed whole. For patients with severe diarrhea, dose may be reduced to 72mcg (available for CIC). Pediatric use is contraindicated in patients under 6 years; avoid in patients 6-17 years due to risk of serious dehydration.
Safety & Side Effects
Linaclotide is a prescription-only medication with a generally favorable safety profile in adults given its minimal systemic absorption; however, it carries an FDA black box warning contraindicating use in pediatric patients under 6 years due to risk of fatal dehydration, and it should be avoided in patients with known or suspected mechanical gastrointestinal obstruction. Diarrhea can be severe enough to necessitate dose reduction or discontinuation in some patients.
Possible Side Effects
- !Diarrhea (most common, occurring in up to 20% of patients, may be severe)
- !Abdominal pain or cramping
- !Flatulence and abdominal distension
- !Nausea
- !Fecal urgency
- !Gastroesophageal reflux
- !Dehydration and electrolyte imbalance (particularly with severe diarrhea)
- !Headache
Interactions
- -No significant drug-drug interactions identified due to minimal systemic absorption, but concurrent use of other laxatives or stool softeners increases risk of diarrhea and dehydration
- -Caution with diuretics (e.g., furosemide, hydrochlorothiazide): additive dehydration and electrolyte depletion risk
- -NSAIDs and aspirin may worsen GI mucosal irritation when used concurrently
- -Caution in patients taking medications with narrow therapeutic windows (e.g., warfarin, digoxin) due to potential for altered GI absorption from accelerated intestinal transit
- -Magnesium-containing antacids or supplements may have additive laxative effects, increasing diarrhea risk
Cost & Where to Buy
Linaclotide is a prescription-only brand-name drug (Linzess) with no generic currently available in the US; manufacturer savings cards may reduce out-of-pocket costs significantly for commercially insured patients. GoodRx and patient assistance programs can lower costs substantially.
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