FDA warns of serious skin reactions with the anti-seizure drug Onfi

The US Food and Drug Administration is warning the public that the anti-seizure drug Onfi (clobazam) can cause rare but serious skin reactions that can result in permanent harm and death. The drug was launched in the USA in late 2011 by Danish CNS drug specialist Lundbeck (LUND: DC; The Pharma Letter January 3, 2012).

The FDA said it has approved changes to the Onfi drug label and the patient Medicines Guide to describe the risk of these serious skin reactions. Patients taking Onfi should seek immediate medical treatment if they develop a rash, blistering or peeling of the skin, sores in the mouth, or hives. Health care professionals should discontinue use of Onfi and consider an alternate therapy at the first sign of rash, unless it is clearly not drug-related, the agency stated.

These rare but serious skin reactions, called Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN), can occur at any time during Onfi treatment. However, the likelihood of skin reactions is greater during the first eight weeks of treatment or when Onfi is stopped and then re-started, the FDA noted. All cases of SJS and TEN in the FDA case series have resulted in hospitalization, one case resulted in blindness, and one case resulted in death.