Gabapentin HCl is primarily used in the treatment of epilepsy, helping to control seizures by stabilizing electrical activity in the brain. It is also widely prescribed for managing neuropathic pain, such as that caused by diabetic neuropathy or postherpetic neuralgia, by modulating the transmission of pain signals. Additionally, it is sometimes used off-label to treat conditions like restless legs syndrome, migraines, and certain anxiety disorders. Its ability to interact with calcium channels in the nervous system makes it effective in reducing abnormal neuronal excitability.