Learn about Horizant (Gabapentin Enacarbil Extended-Release Tablets) may treat, uses, dosage, side effects, drug interactions, warnings, patient labeling, reviews, and related medications. Gabapentin oral capsule can cause mild or serious side effects. The following list contains some of the key side effects that may occur while taking gabapentin. Gabapentin (Neurontin) Side Effects: Neurontin (gabapentin) is an anti-epileptic medicine utilized to cure seizures. Neurontin is utilized alone or along with some additional drugs to deal with seizures due to epilepsy in men and women and children who are a minimum of 8 to 15 years old. Initially, 300 mg PO 3 times per day. May increase using 300, 400, 600, or 800 mg dosage forms PO given 3 times per day. Effective dose is 900—1800 mg/day, but up to 2400 mg/day has been used long-term. Gabapentin side effects in dogs. While most of the gabapentin side effects in dogs are limited to mild sedation and ataxia, there are a number of more serious side effects that are associated with exceeding the recommended dosage. Gabapentin (Neurontin, Gralise, and others) is a prescription drug used to treat seizure disorders and nerve damage from shingles. Off label uses (non-FDA approved) include fibromyalgia, headaches, and hot flashes. Common side effects are fatigue, nausea, hostility, dizziness, and tremors. NEURONTIN® Capsules, for Oral Use. NEURONTIN® (gabapentin) Tablets, for Oral Use. NEURONTIN® (gabapentin) Oral Solution. DESCRIPTION. The active ingredient in NEURONTIN capsules, tablets, and oral solution is gabapentin,which has the chemical name 1-(aminomethyl)cyclohexaneacetic acid. Gabapentin is a prescription medication used for the treatment of epilepsy and seizures. It is also used to treat the herpes virus, as well as shingles. It is FDA-approved for the treatment in adults and children ages 12 and older, and is sometimes used in small doses to treat epileptic children ages 3 and up. Side effects of gabapentin can be. The side effects of gabapentin can lead to potentially severe physical effects in the short-term and long-term. Learn more about the long-term effects of gabapentin. Do you know all the ways that alcohol use and abuse can affect your body? What about the ;ong-term and short-term side-effects of alcoholism? Read on to learn more about negative effects of alcohol abuse.