Nupentin 300 mg capsules. Prescription required . Contains the active ingredient gabapentin. Apo-Gabapentin is used to: • Control epilepsy, a condition that causes repeated seizures (fits). There are many different types of seizures, ranging from mild to severe • Treat neuropathic pain (pain due to nerves being damaged or affected). How it works Gabapentin belongs to a group of medicines called anticonvulsants. It is thought to work by controlling brain chemicals which send signals to nerves to help control seizures or neuropathic pain. This medicine helps to relieve pain.