Merck has initiated an urgent recall of one lot of its prescription allergy medication after discovering that bottles labeled as 10mg tablets actually contain 40mg tablets. The mix-up poses a risk of overdose, particularly for pediatric patients.
The recall affects lot number MK-7840-2026A of montelukast sodium tablets distributed to pharmacies in the eastern United States between March 15 and April 5, 2026. Approximately 15,000 bottles are affected.
At the 40mg dose, patients could experience elevated liver enzymes, neuropsychiatric symptoms, and in severe cases, liver damage. Children prescribed the 10mg dose are at greatest risk due to their lower body weight.
Pharmacies have been instructed to immediately quarantine any remaining inventory from the affected lot and contact patients who received the mislabeled medication. Patients currently taking medication from the recalled lot should contact their healthcare provider immediately.
Merck has traced the error to a packaging line malfunction at its manufacturing facility and has implemented corrective actions. The company reported the incident to the FDA within 24 hours of discovery and initiated the recall voluntarily.
