European Union (EU) regulators have said that use of Trobalt, an epilepsy drug developed jointly by GlaxoSmithKline and Valeant Pharmaceuticals should be restricted except in very specific cases. Trobalt is sold under the brand Potiga in the United States. Epilepsy is a brain disorder involving excessive brain nerve cell activity.
Trobalt, said EU regulators, should only be used by patients for whom all other anti-epileptic drugs have either been inadequate or not tolerated, according to Reuters. The announcement, said the European Medicines Agency (EMA), came after reports of abnormal coloring of the skin, nails, lips, and eye tissues, including the retina, in some patients taking Trobalt. A comprehensive eye examination is recommended before Trobalt treatment is initiated and should be repeated at least twice-yearly during treatment, said the EMA.
In 55 patients treated with Trobalt in long-term studies, 15 developed retinal pigmentation, the EMA said. This abnormal change in coloring can cause impaired vision, Reuters explained. The U.S. Food and Drug Administration (FDA) just issued a similar warning for Potiga.
“All patients taking Potiga should have a baseline eye exam, followed by periodic eye exams,” the FDA said in a recent statement. The agency said it was collaborating with Glaxo and Valeant and evaluating available data, but said it is not known if Potiga’s side effects are temporary or permanent, according to a prior Reuters report. “It is not yet known whether the retinal pigment changes caused by Potiga lead to visual impairment, although several patients have been reported to have impaired visual acuity,” the FDA said.
Skin discoloration was observed after four years of Potiga treatment in most cases, but had appeared sooner than that in some patients, said the FDA. “The retinal abnormalities and skin discoloration … have been reported only in patients who were originally enrolled in Potiga clinical trials, and who have generally taken the drug for a long period of time,” the FDA said in a release just posted on its website.
A Glaxo spokeswoman recently said the firm would revise Potiga’s prescribing information. “Late last year, GSK informed clinical trial investigators and regulators, including the FDA, of a new adverse drug reaction which is discoloration of nails, lips, and skin and in response to this information,” spokeswoman Sarah Alspach said.
Potiga, which was approved in June 2011 for the treatment of petit mal seizures, the most common seizure in people with epilepsy, has two generic names, ezogabine in the U.S. and retigabine in the rest of the world. Retigabine was approved in the European Union in 2011 and is marketed under the brand Trobalt.
We recently wrote about other anti-seizure medications linked to an increased risk of autism in the babies of women who took the drugs during pregnancy. Valproate is used in the treatment of epilepsy; however, its use by pregnant women was associated with a significantly increased risk of their babies developing autism, according to a study in the Journal of the American Medical Association. Valproate has also been linked to increased risks for congenital malformations and delayed cognitive development; little information is available on valproate’s risks for other significant neuropsychiatric disorders. Also, a prior Danish study revealed additional evidence that fetal exposure to Depakote, specifically its active ingredient, valproate, increases a baby’s risk of developing autism spectrum disorders (ASD) three-fold. Depakote, approved for the prevention of migraines, treating acute manic episodes in bipolar patients, and halting seizures in adults and children, has been associated with birth defects when taken by pregnant women.
Just prior, 26 women filed lawsuits claiming that the makers of Depakote illegally marketed the drug for off-label purposes and failed to warn of the side effects of the drug. Each of the women claimed they were prescribed and took Depakote just before getting pregnant or during the first trimester of their pregnancy and that the drug caused them to give birth to children with a wide array of severe, some life-threatening, birth defects.