April 26 (Reuters) - The U.S. Food and Drug Administrationsaid the an anti-seizure drug developed by ValeantPharmaceuticals Inc and co-marketed withGlaxoSmithKline Plc may cause eye and skin problems.
The U.S. health regulator warned that the drug, Potiga, maycause bluish skin predominantly around lips, fingers and toesand pigment changes in the retina, which may lead to loss ofvision. ()
"All patients taking Potiga should have a baseline eye exam,followed by periodic eye exams," the FDA said in a statement.
The regulator said it was working with the drugmakers andevaluating available information, and added that it does notknow whether the changes caused by Potiga are permanent.
"It is not yet known whether the retinal pigment changescaused by Potiga lead to visual impairment, although severalpatients have been reported to have impaired visual acuity," theFDA said.
The regulator said the skin discoloration was observed afterfour years of treatment with Potiga but it appeared sooner insome patients.
"The retinal abnormalities and skin discoloration ... havebeen reported only in patients who were originally enrolled inPotiga clinical trials, and who have generally taken the drugfor a long period of time," FDA said in a release posted on itswebsite on Friday.
A Glaxo spokeswoman said the company would revise theprescribing information for the drug and talk to the regulators.
"Late last year, GSK informed clinical trial investigatorsand regulators including the FDA of a new adverse drug reactionwhich is discoloration of nails, lips and skin and in responseto this information," Sarah Alspach, based in Washington, said.
Valeant could not be immediately reached for comment.
Potiga was approved in June 2011 for the treatment ofpartial seizures, the most common type of seizure in people withepilepsy, a brain disorder characterized by excessive activityof nerve cells in the brain.
The drug generated sales of about $12 million in 2012.Analysts are expecting sales to rise to $376 million by 2016,according to Thomson Reuters data.
The drug has two generic names, ezogabine in the U.S. andretigabine in the rest of the world. It was approved in theEuropean Union in 2011 where it is marketed under the trade nameTrobalt.
Glaxosmithkline (GSK)