Beasley, Allen, Crow, Methvin, Portis & Miles, P.C.

The U.S. Food and Drug Administration is investigating the possibility that phenytoin and fosphenytoin sodium increase the risk of serious skin reactions, such as Stevens Johnson Syndrome (SJS) and toxic epidermal necrolysis (TEN), according to FDA MedWatch. Phenytoin and fosphenytoin are used to control tonic-clonic (grand mal) and complex-partial seizures in epilepsy.

In a recent Information for Healthcare Professionals sheet, the FDA described the increased risk of SJS/TEN with another antiepileptic drug, carbamazepine, in patients of Asian ancestry with the HLA-B*1502 allele. HLA-B is a human gene that provides instruction for making a protein that plays a critical role in the immune system. It is part of a family of genes called the human leukocyte antigen (HLA) complex. This complex helps the immune system distinguish the body’s own proteins from proteins made by viruses or bacteria. Several variations of the HLA-B gene are associated with adverse reactions to certain drugs.

SJS is a disorder of the skin and mucous membranes and often begins with flu-like symptoms followed by inflammation of mucous membranes and a painful red or purplish rash that spreads and blisters. It eventually causes the top layer of skin to die and shed.

Until the FDA completes its review, the agency warns healthcare providers who are considering the use of phenytoin or fosphenytoin for their patients to be aware of the risks and benefits described in the current prescribing information for the drug. Healthcare providers should consider avoiding phenytoin and fosphenytoin as alternatives for carbamazepine in patients who test positive for HLA-B*1502.

This entry was posted on Monday, December 1st, 2008 at 9:08 am and is filed under News. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.