Drug Approved for Treatment of Postherpetic Neuralgia (PHN)
By Jennifer Warner
WebMD Health News
Reviewed by Laura J. Martin, MD
Horizant (gabapentin enacarbil) has been approved to treat postherpetic neuralgia (PHN) in adults.
Researchers say about 1 million people in the U.S. develop shingles each year. Of these, about 10% will go on to develop PHN.
PHN causes pain in the area affected by shingles, often in the torso, and can last for months or even years after the initial infection.
New Use for Drug
Horizant was approved in 2011 to treat restless leg syndrome.
In approving Horizant to treat PHN, the FDA evaluated the safety and effectiveness of the drug in three clinical trials involving 574 people.
Researchers don't know exactly how Horizant works to reduce PHN-associated symptoms, but studies have shown that gabapentin can help relieve nerve-related pain.
The drug may also impair a person's ability to drive a car. People taking Horizant should not drive a car or operate heavy machinery until they have enough experience with the drug to determine whether their driving ability is affected.
Horizant is a slightly less active form of the antiepileptic drug gabapentin. This type of antiepileptic drug increases the risk of suicidal thoughts and behaviors.
Horizant also increases these risks, and people taking the drug should talk to their health care provider about any new or worsening depression or suicidal thoughts.
The drug was developed by XenoPort Inc. and is marketed by GlaxoSmithKline.
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