Restless Leg Syndrome Drug Gets New Indication

FDA approves gabapentin enacarbil after a twelve week trial.

The FDA has approved the restless legs syndrome drug gabapentin enacarbil (Horizant) to treat postherpetic neuralgia.

The drug is administered in one 600 mg dose for the first 3 days of treatment, followed by 600 mg doses twice daily on day four and onward, a statement from makers GlaxoSmithKline and XenoPort said.

Patients with renal impairment should have adjusted doses, the statement added.

Safety and efficacy for the new indication were evaluated in a 12-week principal efficacy trial and two supportive studies of a combined 574 patients.

Adverse events in the studies included somnolence, dizziness, headache, nausea, and fatigue.

Patients taking anti-epileptic drugs, including other gabapentin formulations, may be at increased risk for suicidal ideation and behavior, as well as potentially fatal multi-organ hypersensitivity, symptoms of which include fever, rash, and lymphadenopathy.

The drug should be tapered to once daily for a week before ceasing treatment to reduce risk of withdrawal seizure, the statement said.

The drug was initially approved for the treatment of moderate-to-severe primary restless legs syndrome in April 2011.

By Cole Petrochko