Anti-seizure drugs, such as gabapentin, are often used to treat chronic pain. Pregabalin (Lyrica), a drug similar to gabapentin, was the first medication approved by the Food and Drug Administration (FDA) to treat fibromyalgia. While gabapentin hasn't been approved by the FDA for the treatment of fibromyalgia, some doctors may prescribe it off-label for such use.
Gabapentin and pregabalin were originally approved to treat certain types of epilepsy and nerve pain. Both drugs work by limiting the release of pain-communicating chemicals by nerve cells in the brain and spinal cord. The most common side effects of both drugs are dizziness and drowsiness.