Cephalon shares were hit this week by fears that the firm’s attention-deficit hyperactivity disorder drug Sparlon, which is currently under review by US regulators, may be slapped with a suicide warning on its label.

The fears were sparked by documents from a Food and Drug Administration advisory committee briefing, posted on its website, which describe 31 cases of suicidality, aggression or psychosis in patients taking Sparlon (modanifil) in clinical trials.

The Committee is due to meet on March 22 to review the safety of ADHD therapies, such as Sparlon, Shire and Noven’s Daytrana (methylphenidate transdermal system; also under review with the FDA) and Shire’s Adderall (mixed amphetamine salts). Cephalon’s New Drug Application for Sparlon is up for review the following day and, if approval is granted, it seems likely that the agent will be branded with a cautionary warning of some kind.

But the general feeling is that Sparlon could still offer important advantages over rival drugs such as Eli Lilly’s Strattera (atomoxetine), which already carries a suicide warning, and Adderall, as it is associated with a lower potential of abuse as well as less risk to heart health, according to media reports.