The FDA has approved Avanir Pharmaceuticals’ drug for treating a
condition known as pseudobulbar effect — involuntary emotional outbursts
associated with brain disease or injury.

Its shares more than doubled in aftermarket trading, adding
$2.60 to $5.02. The stock had shed 39 cents, or nearly 14 percent, to $2.42
during the regular session.

The drug, dubbed Nuedexta, should be available by
prescription in the first quarter of next year, the company said.

“The approval of Nuedexta also marks Avanir’s
transition toward becoming a commercial enterprise, ready to support the
successful launch of the first FDA-approved treatment for (pseudobulbar
effect),” said Keith Katkin, Avanir’s president and chief executive.

In 2006, the FDA asked for more information on the drug to
consider it for approval. The company started an additional late-stage study on
a low-dose version of the drug in 2007 following an agreement with the agency
and submitted that data earlier this year.