In a recent Food and Drug Administration (FDA) announcement, it was declared that Onfi (Clobazam) could possibly cause a rare and deadly skin reaction in certain patients.  Reports of Stevens Johnson Syndrome (SJS) and Toxic Epidermal Necrolysis (TEN) have been reported amongst patients who had taken Onfi, which prompted the FDA announcement.

The alert was made public on Dec. 3, 2013, when the FDA stated that the famous anti-seizure medication, Onfi, had the potential to cause rare, but serious skin reactions, which could lead to permanent side effects, and death.  The most common of these side effects include: rash, blistering or peeling of the skin, sores in the mouth, and hives.

“These skin reactions, Stevens Johnson Syndrome (SJS) and Toxic Epidermal Necrolysis (TEN) can occur at any time during use of Onfi. All reported FDA cases of SJS and TEN have resulted in hospitalization. One case resulted in death while another resulted in blindness,” according to the FDA’s warning.

The FDA recommends that patients monitor their side effects carefully for the first eight weeks of taking Onfi, and seek medical treatment if they experience any side effects.  Typically signs for TEN and SJS appear within the first two weeks of starting the medication, and occur more often in adults than children.  In the past year, there have been twenty reported cases of TEN; six in the United States, and fourteen in other countries.

Onfi is an anti-seizure medication that is used to treat a severe form of epilepsy, known as Lennox-Gastaut Syndrome.  It is often used in combination with other medications, and can be prescribed to both adults and children.  As of now, Onfi’s label is in the process of being updated to include the possibility of SJS and TEN occurrences; for many patients, this warning came too late.  If not treated immediately, TEN can have fatal consequences, with each case needing some hospitalization.

Many other medications have been shown to cause SJS and TEN in patients, but many of their labels do not warn against this possibility.  For this reason, many drug manufacturers are facing product liability and negligence charges, for inadequately describing the side effects.

Overview of Toxic Epidermal Necrolysis Complications

Toxic Epidermal Necrolysis (TEN), also known as Lyell’s syndrome, is a rare and life-threatening allergic skin reaction, that is specifically caused by medications.  It is infamously known for covering the body in painful and colorful skin lesions, taking up to 90% of the skin’s surface area.

Toxic Epidermal Necrolysis is a more severe form of Stevens Johnson Syndrome (SJS), and normally follows its weaker cousin; occurrences of TEN appearing without SJS has also been reported.  There is currently debate amongst some medical experts if these are two separate conditions, or if it is a worsening condition.

The confusion with SJS occurs when the skin lesions cover up between 10% to 30% of the body, because SJS typically does not extend beyond that.  As mentioned before, TEN can have the lesions spread almost completely over the patient, causing massive skin detachment.  Due to the nature of the injuries brought out by these conditions, patients are treated the same as burn patients.  While a very rare condition, there is a significant mortality rate amongst the occurrences, being between 30% and 40%.