FDA Approves New Restless Legs Syndrome Drug

April 7, 2011 -- The FDA has approved a new drug, Horizant Extended Release Tablets, as a once-daily treatment for moderate-to-severe restless legs syndrome. 

Restless legs syndrome (RLS) is a disorder that causes a strong urge to move the legs. People who have restless legs syndrome describe unpleasant feelings in their legs, such as pulling, itching, tingling, burning, or aching. Moving their legs temporarily relieves these feelings. The urge to move often happens when someone is inactive. The symptoms typically are worse in the evening and early morning.

"People with restless legs syndrome can experience considerable distress from their symptoms. Horizant provides significant help in treating these symptoms," Russell Katz, MD, director of the division of neurology products in the FDA's Center for Drug Evaluation and Research, states in an FDA news release.

The FDA approved Horizant based on two 12-week studies done in adults. Those studies showed improvement in restless legs syndrome patients taking Horizant compared to those taking a placebo.

Horizant's active ingredient is gabapentin enacarbil, which becomes gabapentin in the body. Gabapentin is an antiseizure drug that is also used to treat RLS. Lifestyle changes -- such as exercising, building healthy sleep habits, and cutting back on caffeine, alcohol, and tobacco -- are also recommended.

The FDA states that Horizant "may cause drowsiness and dizziness and can impair a person's ability to drive or operate complex machinery." Like all antiseizure drugs, Horizant will carry a warning about the risk that it may cause suicidal thoughts and actions in a small number of people. Horizant will also come with a medication guide outlining its uses and risks.

Horizant is not recommended for patients who must sleep during the daytime and remain awake at night, according to a news release from the drug companies GlaxoSmithKline and XenoPort, which developed the drug.