Shire Pharmaceuticals has been given a slap on the wrist by US regulators over misleading promotional materials regarding its attention-deficit hyperactivity disorder drug Vyvanse.

The US Food and Drug Administration issued a warning letter to the drugmaker which states that promotional magnets advertising Vyvanse (lisdexamfetamine dimesylate) violated certain marketing rules by failing to adequately disclose the risks associated with the medicine.

This, it argues, gave the impression that the drug is safer and more effective than has been demonstrated in clinical trials, and therefore misbrands Vyvanse in violation of the Federal Food, Drug, and Cosmetic Act.

Vyvanse is linked with a number of serious risks, some of which are fatal, and carries a Boxed Warning because of the potential for abuse. In addition, there are numerous contraindications and other warnings including cardiovascular and psychiatric adverse events, as well as less serious side effects such as vomiting, decreased appetite and insomnia.

But while the promotional magnet carries the statement, 'please see accompanying Full Prescribing Information, including Boxed Warning,' this does not mitigate the omission of indication and risk information, the FDA said.

The agency has asked Shire to stop distributing the magnets immediately, as well as submit a comprehensive plan “to disseminate truthful, non-misleading, and complete corrective messages" regarding the issues raised in the warning letter.