XenoPort, a biopharmaceutical company, originally developed the drug, and GlaxoSmithKline has been responsible for manufacturing and commercialization (advertising and distributing) of Horizant until April 30, 2013.
There’s a manufacturing delay surrounding the May 1, 2013 handoff, and it will take some time to get Horizant back into pharmacies. The current estimate for Horizant to be fully available again? Not until June 2013.
For more information before May 1, call GlaxoSmithKline at 1-888-825-5249
For more information on May 1 and after, contact XenoPort at 1-877-XENOPRT (1-877-936-6778)
Update: As of 5/24/2013, XenoPort has notified the FDA that the Horizant 600 mg tablet is available. It may take some time for pharmacies to restock, so the June 2013 availability date is still likely an accurate estimate.