FDA Equivalence Concerns Draw Attention to ADHD Generics

Two FDA approved generic versions of Concerta® tablets may not be producing the same therapeutic effects as the brand name version of the drug in some patients, according to an FDA drug safety release. The two generic methylphenidate hydrochloride extended-release tablets that are raising concerns, which are used to treat attention-deficit hyperactivity disorder in adults and children, are manufactured by Mallinckrodt Pharmaceuticals and Kudco Ireland Ltd.


The FDA conducted an analysis of adverse event reports, an internal re-examination, and laboratory testing of the generic products manufactured by Mallinckrodt and Kudco. The FDA investigation led the agency to believe that the generics are not releasing the drug in the body at the same rate as they brand name drug Concerta, manufactured by Janssen Pharmaceuticals, Inc. While the intended therapeutic effects of Concerta are achieved through a slow release of the drug, which takes place over a long period—10-12 hours—the FDA believes that the Mallinckrodt and Kudco generics are releasing the drug over a shorter period of time—7 to12 hours—which may result in patients not receiving the desired effect of the drug.


As a result of its findings, the FDA has changed the therapeutic equivalence rating for the generic Mallinckrodt and Kudco products from AB to BX. While the products are still approved by the FDA, the downgrade means that the generics are no longer recommended by the FDA as automatic substitutes for Concerta. In other words, the drugs can still be prescribed but they cannot be substituted by a pharmacist as identical to Concerta by a pharmacy. As a result of its findings, the FDA has also updated a draft guidance related to bioequivalence testing for methylphenidate hydrochloride extended-release tablets.


The FDA release clarifies that no serious safety concerns have been identified with the generic drugs. The FDA indicates that patients should not alter their treatments unless they or a health care professional believe the generic drugs are not producing the desired effects.