Researchers reported findings on leucovorin dispensing rates in the New England Journal of Medicine on August 12, 2026. The data showed that President Trump's September 2025 promotion of the drug as an autism treatment triggered a measurable surge in pediatric prescriptions across the United States.

A Lancet study analyzing a smaller dataset based on emergency departments and outpatient clinics found an increase in prescriptions for leucovorin following the briefing for children 5 to 17 years old.

Leucovorin is a form of the essential vitamin folic acid. The U.S. Food and Drug Administration approved leucovorin for use with certain genetic disorders and to help reduce the side effects of chemotherapy drugs. The FDA approved leucovorin for cerebral folate deficiency in March 2026.

FDA officials stated there was not enough evidence to support using leucovorin for autism. There have not been large, randomized trials evaluating the efficacy or long-term safety of leucovorin for children with autism. The American Academy of Pediatrics does not recommend leucovorin for autism due to lack of evidence regarding dosing, effectiveness, and safety.

"Our study demonstrates the power of the federal government to influence clinical practice," says Kao-Ping Chua, a pediatrician and health policy researcher at the University of Michigan Medical School. "The concern is that clinicians are increasingly prescribing an unproven drug with an unclear safety profile to children."

Why It Matters

The documented rise in prescriptions follows a public endorsement by the president, illustrating how federal statements can alter clinical behavior even without regulatory approval for a specific condition. The studies show that over 47,000 children received the medication during a period when major medical organizations cited a lack of evidence for its use in autism treatment.

The divergence between the pediatric surge and stable adult dispensing rates shows the specific impact of the announcement on child healthcare providers. With no large randomized trials evaluating long-term safety for this population, the prescribing trend prompts questions about adherence to established clinical guidelines.

Timeline

The pharmacy dispensing rate for leucovorin prescriptions for children in the United States was roughly 5 per 100,000 in the week before the September 22, 2025 announcement. President Trump promoted the drug leucovorin as a potential therapeutic for autism at a White House briefing on September 22, 2025. More than 150,000 prescriptions for leucovorin were given to over 47,000 children from the end of 2024 to the end of 2025.

Masuu Global Solutions LLC, U.S. Agent for Extrovis AG, et al. Withdrawal of Approval of 11 Abbreviated New Drug Applications; Correction — Masuu Global Solutions LLC, U.S. Agent for Extrovis AG, et al. Withdrawal of Approval of 11 Abbreviated New Drug Applications; Correction. The Food and Drug Administration (FDA) is correcting a notice that appeared in the Federal Register on February 20, 2026. Researchers reported the findings on leucovorin dispensing rates in the New England Journal of Medicine on August 12, 2026.

What's New

A study titled "Changes in paracetamol and leucovorin use after a White House briefing" was published in 2026 in The Lancet. This additional reporting provides context on the scope of the prescribing changes observed in emergency departments and outpatient clinics.