The U.S. Food and Drug Administration is revising the labeling of all extended-release stimulants to treat attention-deficit hyperactivity disorder to warn about the risk of weight loss and other side effects in patients younger than 6 years. The agency is requiring a “limitation of use” section in the prescribing information of all extended-release stimulants to include a statement on higher rates of adverse reactions in these young children. Extended-release stimulants are not approved for children below 6, but doctors can prescribe them “off label” to treat ADHD. The agency said it assessed data from clinical trials of extended-release formulations of amphetamine and methylphenidate for ADHD treatment, finding that, compared to older children, patients younger than 6 have higher levels of the drug in their bodies as well as higher rates of side effects. For these reasons, the benefits of extended-release stimulants may not outweigh the risks in patients younger than 6, according to the regulator.