FDA restricts dosing of prescription acetaminophen

Key Points

The Food and Drug Administration is limiting the amount of acetominophen in prescription drug products, primarily combinations of acetaminophen and opioids. The new dosing limit is 325 mg per tablet, capsule, or other dosing unit. The opioid component of combination products is not affected by the new rule

FDA is also requiring new black-box warnings to highlight the potential for severe liver failure and the potential for severe allergic reactions. The new rules take effect in early 2014.

A recognized problem

"The problem is particularly severe in combination products and in patients taking multiple products that include acetaminophen," he added. "The risks of liver failure can be exacerbated as you begin to escalate dosage in order to obtain more opioid. The healthcare community has been trying to get its hands around this for some time." Calabrese is also clinical editor for Drug Topics' sister publication Formulary.

FDA panel recommendation

The new dosage limit falls short of a recommendation made by an FDA advisory panel in 2009 to ban combination products that include acetaminophen.

The panel has been evaluating the risk of liver failure associated with acetaminophen for several years. A scant majority voted to ban combination products entirely, while a wide majority favored a black box warning. FDA estimates that pharmacies filled nearly 200 million prescriptions for acetaminophen products in 2008, making them among the most widely used prescription drugs.

"Lots of people have taken them [combination products] and will continue to do so," said Sandra Kweder, deputy director of FDA's office of new drugs. "Our goal is to make them safer."