The U.S. Food and Drug Administration (FDA) released a safety warning about the anti-seizure medication Onfi and a possible link to Stevens Johnson Syndrome (SJS), a rare but debilitating skin condition that can be likened to serious burns.

Onfi (clobazam) is manufactured by Lundbeck, a Danish Pharmaceutical company. The potential for blisters and skin rash is listed on the product web page for Onfi, but SJS is not specifically referenced. The FDA has since issued the safety release and is mandating updates to the prescribing information for the product to note the possibility of Onfi SJS.

What Is Onfi?

Onfi (clobazam) is an anti-seizure drug in category of drugs called benzodiazepines and was approved on Oct. 21, 2011. Onfi is often prescribed in combination with other medications in an attempt to treat and prevent seizures associated with a severe form of epilepsy called Lennox-Gastaut Syndrome.

Lennox-Gastaut syndrome usually begins before 4 years of age, and can be caused by a number of conditions, including brain malformations, severe head injuries, central nervous system infections, and inherited degenerative or metabolic conditions. In 30 percent to 35 percent of patients, no cause can be found.

It is believed that less than 200,000 people in the United States have been diagnosed with Lennox-Gastaut syndrome. Lennox-Gastaut syndrome accounts for about 4 percent of all cases of childhood epilepsy and is more common in males than in females.

Onfi SJS Skin Reactions

Onfi SJS skin reactions are extremely dangerous, painful, and disfiguring and can lead to SJS’ more serious cousin, Toxic Epidermal Necrolysis (TEN). Both Onfi skin reactions are considered medical emergencies that involve a painful and spreading rash that eventually kills the top layer of a person’s skin.

People with SJS can die from complications such as infection, sepsis, blindness and organ damage. TEN is an even more severe condition that often involves hospitalization and treatment in intensive care or burn units.

Stevens Johnson Syndrome can begin as a rash, then progress rapidly to blisters over much of the body. The interior of the mouth can also be affected, as are the eyes. Cases of blindness have been reported. Patients, whose eyesight recovers, have often been left with permanent light sensitivity.

SJS symptoms have been likened, in some reports, to the body burning from the inside out. Most patients are treated in burn units after hospitalization, as TEN and SJS symptoms are similar to that of burns. Skin has been known to slough away in sheets, and SJS patients – from adults to children – can become very ill. Those who survive are often permanently scarred.

FDA Warns About Onfi SJS

The FDA Drug Safety Communication came after a review of adverse events that linked Onfi to 20 skin reactions involving Stevens Johnsons Syndrome (SJS) and Toxic Epidermal Necrolysis (TEN). The FDA is advising clinicians to closely monitor patients taking Onfi for SJS and TEN, especially at the start of therapy or when the drug is reintroduced.

Yet, despite the FDA’s safety warning, Onfi sales continue to soar. Regardless of the fact that there are not that many patients prescribed Onfi on a monthly basis, Lundbeck has seen an increase in profit of 122 percent from the third quarter of 2012 to the third quarter of 2013. Onfi sells for between $110 and $900.

Of the Stevens Johnson Syndrome skin disease cases reported to the FDA’s adverse event reporting system, all patients were hospitalized. One case resulted in blindness and another individual died. Onfi SJS Lawsuits have been filed alleging Lundbeck failed to warn the public of the risk of Stevens Johnson Syndrome associated with this drug.