Linaclotide

Linaclotide is approved for several types of constipation-related conditions. All approved forms in the U.S. are available as Linzess capsules taken by mouth.

• Irritable bowel syndrome with constipation (IBS-C) — Linzess is approved for adults and for children 7 years of age and older.
• Chronic idiopathic constipation (CIC) — Linzess is approved for adults only. "Idiopathic" means no identifiable underlying cause.
• Functional constipation (FC) — Linzess is approved for children 2 years of age and older.

Linaclotide activates a receptor on the surface of intestinal cells called guanylate cyclase-C (GC-C). When activated, GC-C triggers a rise in a signaling molecule called cGMP (cyclic guanosine monophosphate). This causes intestinal cells to secrete more chloride and bicarbonate into the gut, drawing water in, softening stool, and speeding up transit through the intestine. In IBS-C, linaclotide also appears to reduce visceral pain (pain felt deep in the belly) by lowering the activity of pain-sensing nerves — a separate benefit beyond just relieving constipation.

Linzess is taken once daily by mouth, on an empty stomach, at least 30 minutes before your first meal — at roughly the same time every day. Do not crush or chew the capsules. If you miss a dose, skip it and take your next dose at the scheduled time; never take two doses at once.

• If you can't swallow capsules, the beads inside can be mixed with a small amount of room-temperature applesauce or water and swallowed right away.
• For patients with feeding tubes, a water-based method is available — follow your prescriber's specific instructions.
• Your prescriber will choose the right dose for your condition and age — follow their guidance exactly.

The most common side effects of Linzess include:

Severe diarrhea is the most important side effect to act on — if it's bad or doesn't let up, stop Linzess and call your doctor right away to avoid dangerous dehydration. Eating a high-fat meal close to your dose can also make diarrhea worse, so stick to taking it on an empty stomach.

• Never give to children under 2: Linzess is contraindicated (not allowed) in this age group. It can cause rapid, life-threatening dehydration. This is the FDA's highest-level warning.
• Severe diarrhea: If you experience severe diarrhea, stop taking Linzess and contact your doctor immediately. You may need fluids to rehydrate.
• Mechanical gastrointestinal obstruction: Linzess must not be used if there is a known or suspected blockage in the gut — it could make the situation worse.
• Food timing matters: Taking Linzess right after a high-fat meal increases the chance of loose stools and more frequent bowel movements. Always take it on an empty stomach.

Based on lab studies, linaclotide is not expected to interact with other medications in the typical way. It is minimally absorbed into the bloodstream and does not affect the liver enzymes (cytochrome P450 system) that process most drugs. However, the label notes that no formal drug interaction studies have been done in people.

• Food (especially high-fat meals): Taking Linzess right after a high-fat breakfast can increase loose stools and bowel frequency — always take on an empty stomach, 30 minutes before eating.

Not a complete list. The label covers the interactions the manufacturer studied or reported, and our own interaction database does not cover every medicine either. Bring your full medication list, including vitamins and herbal products, to your pharmacist.

• Children under 2 years old: Linzess is completely contraindicated — do not use under any circumstances.
• Children ages 2–6 with IBS-C: Linzess is not approved for IBS-C in this age group; it is only approved for functional constipation (FC) in children 2 and older.
• Known or suspected gut blockage: Do not take Linzess if you have or might have a mechanical obstruction in your intestines.
• Pregnancy: Linaclotide is barely absorbed into the bloodstream, so the risk to a developing baby is considered low — but there isn't enough human data to be certain. Talk to your doctor.
• Breastfeeding: Linaclotide was not detected in breast milk in studies. Your doctor can help weigh the benefits and any potential risks for your baby.
• Kidney or liver problems: Because linaclotide works inside the gut and is not significantly absorbed, kidney or liver impairment is not expected to change how the drug works or is cleared.

In a clinical study where healthy volunteers received a single very large dose of Linzess, the most common reaction was diarrhea — consistent with what's seen at normal doses. If you or someone else takes too much, contact Poison Control or seek medical attention. The main concern would be diarrhea and resulting dehydration.

Linzess works entirely inside the intestine — it is not meant to act on the rest of the body. By activating GC-C receptors on the gut lining, it increases fluid secretion into the intestinal space, which softens stool and speeds up how quickly things move through. Taking Linzess right after a high-fat meal leads to looser stools and more frequent bowel movements compared to taking it on an empty stomach — which is why the empty-stomach recommendation matters.

Linaclotide is remarkably local in its action — it is minimally absorbed from the gut into the bloodstream. Blood levels after standard doses are so low they can't even be measured with standard lab tools. It is broken down within the intestine itself into smaller peptides and naturally occurring amino acids, and a small amount passes out in the stool. Because it stays in the gut, kidney or liver disease doesn't affect how it's processed, and it doesn't interact with the liver enzymes that metabolize most other drugs.

Store at 25°C (77°F); excursions permitted between 15°C and 30°C (59°F and 86°F) . Protect from moisture.