FDA Expands Approval of Linzess for Patients as Young as 2 Years

The FDA expanded the approval of linaclotide (Linzess) to include the treatment of functional constipation in pediatric patients as young as 2 years of age. This regulatory milestone establishes the medication as the first and only FDA-approved prescription therapy for pediatric functional constipation, an area that has historically lacked evidence-based treatment options.¹

Although linaclotide was previously indicated for children 6 years and older, this expanded label now provides a therapeutic path for preschool-aged children between the ages of 2 and 5 years. Functional constipation is a common chronic condition characterized by infrequent, hard stools that are often painful to pass, and it is estimated to affect approximately 3% of children worldwide.^1,2

“This approval extends the use of Linzess to younger patients with functional constipation, addressing an important gap in care for this historically underserved population, as reflected by the FDA’s decision to grant priority review,” Tom McCourt, chief executive officer of Ironwood, said in a news release.¹ “We see this as a natural progression for Linzess that builds on a well-established safety and efficacy profile to expand the impact of our blockbuster medication in [gastrointestinal] care.”

About the FDA Approval

The clinical efficacy supporting the use of this dose in younger children was established in a 12-week, randomized, placebo-controlled phase 3 trial, which demonstrated a significant improvement in the frequency of spontaneous bowel movements compared to a placebo. As a guanylate cyclase-C agonist, linaclotide works by activating receptors in the intestine to increase fluid secretion and accelerate gastrointestinal transit.^1,2

The safety profile of linaclotide in younger pediatric patients was found to be generally consistent with that observed in adults and older children, with diarrhea being the most frequently reported adverse reaction. However, pharmacists must be aware of the boxed warning regarding the risk of serious dehydration, which strictly contraindicates the use of linaclotide in patients under 2 years of age. This warning stems from nonclinical studies in neonatal mice where the drug caused deaths due to dehydration, a risk that cannot be ruled out in human infants due to insufficient data on intestinal receptor expression in that age group. Additionally, the medication remains contraindicated in any patient with a known or suspected mechanical gastrointestinal obstruction.^1,2

The Role of the Pharmacist

For pharmacists dispensing this medication, the recommended dosage for pediatric patients with functional constipation is 72 mcg administered orally once daily. Pharmacists should also counsel caregivers that the medication must be taken on an empty stomach at least 30 minutes before the first meal of the day.³

If a pediatric patient experiences severe diarrhea during treatment, pharmacists should advise caregivers to suspend the medication and contact a physician for rehydration protocols.³

Given the practical challenges of administering oral capsules to young children, the FDA-approved labeling allows for flexible administration methods where the capsule contents may be mixed with 1 teaspoon of room-temperature applesauce or 30 mL of water.^1,3

If mixed with water, the beads should be swirled for 20 seconds and consumed immediately, and caregivers should be instructed not to allow the child to chew the beads. Furthermore, pharmacists should emphasize the importance of keeping the medication in its original bottle, as it contains a specific desiccant packet necessary to protect the capsules from moisture.^1,3

“Managing functional constipation in young children is especially challenging, as this vulnerable patient population often continues to experience persistent symptoms despite treatment with over-the-counter therapies,” Julie Khlevner, MD, a pediatric gastroenterologist at Columbia University Vagelos College of Physicians and Surgeons, said in the news release. “Clinicians must carefully balance safety, efficacy, and the practical realities of what treatments young children are able and willing to take consistently.”

REFERENCES

1. FDA approves use of Linzess (linaclotide) in pediatric patients two years of age and older with functional constipation (FC). News release. Ironwood. May 27, 2026. Accessed May 28, 2026. https://investor.ironwoodpharma.com/press-releases/press-release-details/2026/FDA-Approves-Use-of-LINZESS-linaclotide-in-Pediatric-Patients-Two-Years-of-Age-and-Older-with-Functional-Constipation-FC/default.aspx

2. FDA approves first treatment for pediatric functional constipation. News release. FDA. June 12, 2023. Accessed May 28, 2026. https://www.fda.gov/drugs/news-events-human-drugs/fda-approves-first-treatment-pediatric-functional-constipation?utm_medium=email&utm_source=govdelivery

3. Mayo Clinic. Linaclotide (oral route). March 1, 2026. Accessed May 28, 2026. https://www.mayoclinic.org/drugs-supplements/linaclotide-oral-route/description/drg-20075770