Several paediatricians disagreed, saying they had seen many parents in recent weeks, who said they had stopped giving the medications to their children since hearing about the warnings.

“It really frightened a lot of parents,” said Joanna Sexter of Spring Valley Pediatrics in the District of Columbia. “Sometimes these stories come out, and parents challenge it... This time, that didn’t happen.”

The controversy began when Sharfstein and others petitioned the FDA last spring to restrict use of the products, citing the lack of evidence that they work and reports of children suffering hallucinations, seizures and occasional deaths. The petition prompted the agency to convene a special panel of experts for a two-day hearing.