April 26 The U.S. Food and Drug Administration
said the an anti-seizure drug developed by Valeant
Pharmaceuticals Inc and co-marketed with
GlaxoSmithKline Plc may cause eye and skin problems.
The U.S. health regulator warned that the drug, Potiga, may
cause bluish skin predominantly around lips, fingers and toes
and pigment changes in the retina, which may lead to loss of
"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 and
evaluating available information, and added that it does not
know whether the changes caused by Potiga are permanent.
"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
The regulator said the skin discoloration was observed after
four years of treatment with Potiga but it appeared sooner in
"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," FDA said in a release posted on its
website on Friday.
A Glaxo spokeswoman said the company would revise the
prescribing information for the drug and talk to the regulators.
"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," Sarah Alspach, based in Washington, said.
Valeant could not be immediately reached for comment.
Potiga was approved in June 2011 for the treatment of
partial seizures, the most common type of seizure in people with
epilepsy, a brain disorder characterized by excessive activity
of 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. and
retigabine in the rest of the world. It was approved in the
European Union in 2011 where it is marketed under the trade name