Linaclotide: what it treats, how to take it, side effects
Last updated September 3, 2026.
Linaclotide is a guanylate cyclase-C agonist - it speeds the movement of food and waste through the stomach and intestines. You may know it as Linzess. It is a daily maintenance capsule for a chronic problem, taken on an empty stomach first thing.
What does it treat?
Irritable bowel syndrome with constipation, and certain types of chronic constipation, in adults - and in children 6 and older for some forms. One absolute boundary: children under 2 must never take it - linaclotide caused life-threatening dehydration in young laboratory animals, and the warning is carried at the top of the page.
How do you take it?
One capsule once a day on an empty stomach, at least 30 minutes before a meal - same time daily, so before breakfast is the anchor. Swallow whole. If swallowing is hard: open the capsule and sprinkle the beads on a teaspoon of room-temperature applesauce, swallowed right away without chewing - or swirl the beads in 30 mL of bottled water for at least 20 seconds and drink immediately, rinsing the cup with another 30 mL to catch stragglers. No other foods or liquids for the mixing. Missed dose: skip it if the day has moved on; never double up.
Side effects to know
- Common: diarrhea - the most frequent effect, usually early - plus stomach pain, swelling or fullness or pressure in the stomach area, gas, and headache.
- Serious - stop taking it and call your doctor immediately or get emergency care: unusual or severe stomach pain; bright red or black tarry stools; allergic signs - hives, rash, itching, swelling of the lips, tongue, or throat, shortness of breath, or trouble breathing; dizziness or fainting; and the dehydration pattern - extreme thirst, dry mouth and skin, sunken eyes, or a fast heartbeat.
Who should not take it?
Children under 2, ever, and anyone with a known or suspected gastrointestinal blockage. Diarrhea severe enough to cause the dehydration pattern - thirst, dry mouth, sunken eyes, fast heartbeat - means stop and call. If you become pregnant, call your doctor.
When is it an emergency?
Trouble breathing, throat swelling, fainting, or the dehydration pattern is urgent care. For an overdose, call Poison Control at 1-800-222-1222. Pymander's escalation routing is built and tested specifically for this class of decision; see the safety architecture working paper.
What a Pymander AI doctor consult looks like
Illustrative example, not a real member's messages.
Common questions
Why 30 minutes before breakfast?
The empty-stomach rule is about predictability: taken with food, the drug's effect on the gut gets faster and stronger - which reads as sudden, urgent diarrhea. Taken 30-plus minutes before the first meal, the effect lands gently and on schedule. MedlinePlus sets the window explicitly. Same time every day keeps the rhythm the prescription is aiming for.
Why did I have diarrhea the first week?
The most common effect - the drug speeds the gut, and the first days can overshoot while your system finds the new setting. It settles for most people. The line where it stops being an adjustment: severe pain, red or black stools, or the dehydration pattern - extreme thirst, dry mouth and skin, sunken eyes, fast heartbeat. That cluster means stop taking it and call immediately.
Why the hard rule about children under 2?
The boxed-level warning: linaclotide caused life-threatening dehydration in young laboratory mice, so children under 2 must never take it. For older children (6 and up, for the constipation forms it is approved for) the pediatric dosing is the prescriber's call. In the home: child-resistant cap, out of reach, and the desiccant stays in the bottle.
Why did my doctor rule out a blockage before prescribing it?
A drug that speeds the gut is the last thing you want if the gut is obstructed - pushing against a blockage risks perforation. Suspected or known gastrointestinal blockage is a hard contraindication. That is also why new severe abdominal pain on the drug - a different quality than the usual IBS cramping - gets a call rather than an extra dose.
How long do I stay on linaclotide?
IBS-C and chronic constipation are long games - this is a maintenance medication, taken daily, not a course with an end date. The periodic question at follow-ups is whether the lowest effective dose is still the current one and whether lifestyle measures can carry more of the load. Stopping is simple - no taper - but the constipation returns to baseline.
What happens if I miss a dose of linaclotide?
Take the next one on schedule the following morning - MedlinePlus's missed-dose rule for this once-daily drug is to skip and resume, never double. Two capsules do not mean double the movement; they mean double the diarrhea risk. One missed day costs you one day of regularity, nothing more.