August 2026

Linzess: Dosing, Warnings, and What the Label Says

By Your Health Magazine Health Information Team

You take Linzess before breakfast as directed, but then wonder: Is this the right strength for my condition, what happens if I miss a dose, and how much diarrhea is too much? These are important questions because Linzess comes in several strengths, and the labeled dose depends on the diagnosis and the patient’s age.

The current U.S. Linzess prescribing information, revised in May 2026, explains who may use the medication, how it should be taken, and which warning signs require prompt attention. The following overview summarizes that label for general education. It does not replace the directions provided by your prescriber or pharmacist.

What Is Linzess Used For?

Linzess is the brand name for linaclotide, a prescription medication that acts mainly within the intestines. It activates guanylate cyclase-C receptors, increasing fluid in the intestinal tract and helping stool move through the bowel more efficiently.

The medication is FDA-approved for:

Irritable bowel syndrome with constipation, or IBS-C, in adults and children age 7 and older
Chronic idiopathic constipation, or CIC, in adults
Functional constipation in children age 2 and older

These conditions can look similar, but they are not interchangeable. IBS-C generally includes recurring abdominal pain along with constipation, while CIC involves ongoing constipation without a clearly identified cause. Functional constipation is the term used for certain constipation patterns in children when an underlying disease does not explain the symptoms.

What Doses Does the Label List?

Linzess capsules are available in 72 microgram, 145 microgram, and 290 microgram strengths. According to the current Linzess prescribing information, the labeled once-daily doses are:

Adults with IBS-C: 290 micrograms
Adults with CIC: 145 micrograms; 72 micrograms may be selected based on the person’s presentation or tolerability
Patients age 7 and older with IBS-C: 145 micrograms
Patients age 2 and older with functional constipation: 72 micrograms

These are label summaries, not personal dosing recommendations. A higher capsule strength is not necessarily more appropriate or more effective for an individual. The diagnosis, age, response to treatment, side effects, and other medical considerations all matter. Never change strengths, take additional capsules, or share the medication without consulting the prescribing clinician.

How Should Linzess Be Taken?

The label directs patients to take Linzess on an empty stomach at least 30 minutes before a meal, at approximately the same time each day. Taking it immediately after a high-fat breakfast has been associated with looser and more frequent stools than taking it while fasting, which helps explain the timing instruction.

Capsules should ordinarily be swallowed whole. They should not be crushed or chewed. For someone who cannot swallow a capsule, the label includes specific methods for opening it and administering the beads immediately with room-temperature applesauce or bottled water. The contents may also be given with water through certain feeding tubes. A pharmacist or healthcare professional should demonstrate the approved preparation method rather than having the patient improvise with other foods or liquids.

If a dose is missed, the prescribing information says to skip it and take the next dose at the usual time. Two doses should not be taken together.

The Boxed Warning for Young Children

Linzess carries an FDA boxed warning, the agency’s most prominent medication warning, concerning serious dehydration in children younger than 2. The medication is contraindicated in this age group. This warning is based partly on deaths caused by rapid, severe dehydration in neonatal mice given linaclotide and the lack of sufficient information to determine the risk in children under 2.

This warning does not mean Linzess is prohibited for every child. The current label includes functional constipation in children age 2 and older and IBS-C in patients age 7 and older, using diagnosis-specific doses. Pediatric use should still be managed by a qualified clinician, such as a pediatrician or pediatric gastroenterologist.

Diarrhea Is the Main Safety Concern

Diarrhea is the most commonly reported adverse reaction associated with Linzess. Other common effects in adult trials included abdominal pain, gas, and abdominal distension. Mild changes in stool consistency may occur as the medication increases intestinal fluid, but frequent, intense, or persistent diarrhea should not simply be ignored.

Severe diarrhea can lead to dehydration and electrolyte abnormalities. Postmarketing reports have included cases involving dizziness, fainting, low blood pressure, low sodium or potassium levels, hospitalization, and intravenous fluids. The label instructs patients to stop or suspend the medication and rehydrate if severe diarrhea occurs, with medical guidance obtained promptly.

People taking Linzess may want to review important Linzess safety risks and warning signs so they can distinguish an expected bowel change from a potentially serious reaction.

Who Should Not Take Linzess?

The medication is contraindicated in two groups:

Children younger than 2 years
Anyone with a known or suspected mechanical blockage in the gastrointestinal tract

Possible obstruction symptoms can include severe or worsening abdominal pain, marked swelling, vomiting, and an inability to pass stool or gas. These symptoms require medical evaluation rather than self-treatment with a constipation medicine.

Before starting Linzess, patients should tell their clinician about pregnancy, breastfeeding, allergies, gastrointestinal disorders, and all prescription drugs, over-the-counter medicines, vitamins, and supplements they use. Linaclotide is minimally absorbed into the bloodstream, but available pregnancy data are not sufficient to determine medication-associated risks. The label reports that linaclotide and its active metabolite were not detected in breast milk samples in a small lactation assessment; treatment decisions should still be discussed with a clinician.

Storage and Everyday Safety

Linzess should remain in its original, tightly closed container at room temperature and be protected from moisture. The drying agent should stay in the bottle. Because the capsule could be dangerous for a child for whom it was not prescribed, the container should be kept securely out of children’s sight and reach.

Patients should read the Medication Guide provided with each prescription and ask a pharmacist about anything that is unclear. For additional general medication education, the National Library of Medicine maintains a searchable collection of prescription drug information for patients.

When to Seek Care

Contact the prescribing clinician promptly for severe or persistent diarrhea, unusual abdominal pain, dizziness, fainting, extreme thirst, a racing heartbeat, or other signs of dehydration. Bright red blood in the stool, black or tarry stool, significant rectal bleeding, or worsening abdominal swelling also warrants prompt evaluation.

Seek emergency care for trouble breathing, swelling of the lips, tongue, or throat, collapse, confusion, or symptoms of a severe allergic reaction. A primary care clinician or gastroenterologist can evaluate treatment response and side effects; children may benefit from assessment by a pediatrician or pediatric gastroenterologist.

The Bottom Line on Linzess Prescribing Information

Linzess can help manage specific constipation disorders, but its strengths are not interchangeable and its diarrhea risk deserves attention. The label calls for once-daily use on an empty stomach, prohibits use in children younger than 2, and advises stopping treatment and addressing hydration when severe diarrhea develops. Following the prescription exactly—and contacting the healthcare team when symptoms change—is safer than adjusting the medication independently.