Gabapentin is a prescription medication used to treat adults with nerve pain caused by shingles. Shingles is a painful rash that is caused by the varicellazoster virus, the virus that also causes chickenpox. Gabapentin is also used in combination with other medications to treat partial seizures. Gabapentin belongs to a group of drugs called anticonvulsants, which help treat seizures by decreasing abnormal excitement in the brain. It also works by altering the way the body senses pain. This medication comes in tablet, capsule, and oral solution forms. It is taken up to three times a day, with or without food. The capsules.