Gabapentin comes as a capsule, a tablet, an extended-release (long-acting) tablet, and an oral solution (liquid) to take by mouth. Gabapentin capsules, tablets, and oral solution are usually taken with a full glass of water (8 ounces [240 millilitres]), with or without food, three times a day.

These medications should be taken at evenly spaced times throughout the day and night; no more than 12 hours should pass between doses. The extended-release tablet (Horizant) is taken with food once daily at about 5 PM. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take Gabapentin exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.

If your doctor tells you to take one-half of a regular tablet as part of your dose, carefully split the tablet along the score mark. Use the other half-tablet as part of your next dose. Properly dispose of any half-tablets that you have not used within several days of breaking them.

If you are taking Gabapentin to control seizures or PHN, your doctor will probably start you on a low dose of Gabapentin and gradually increase your dose as needed to treat your condition. If you are taking Gabapentin to treat PHN, tell your doctor if your symptoms do not improve during your treatment.

Your doctor will consider your dosage as per your health condition.

Initial dose: 300 mg orally on day one, 300 mg orally 2 times day on day two, then 300 mg orally 3 times a day on day three

Maintenance dose: 300 to 600 mg orally 3 times a day

Maximum dose: 3600 mg orally daily (in 3 divided doses) -Maximum time between doses in the 3 times a day schedule should not exceed 12 hours

The safety and effectiveness of Gabapentin available under the trade name Gralise or Horizant in patients with epilepsy has not been studied.

Use: Adjunctive therapy in the treatment of partial onset seizures, with and without secondary generalization.

What happens if I miss a dose?

Take the medicine as soon as you can, but skip the missed dose if it is almost time for your next dose. Do not take two doses at one time.

If you take Horizant: Skip the missed dose and use your next dose at the regular time. Do not use two doses of Horizant at one time.

Get emergency medical help if you have signs of an allergic reaction to Gabapentin: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Report any new or worsening symptoms to your doctor, such as: mood or behaviour changes, anxiety, panic attacks, trouble sleeping, or if you feel impulsive, irritable, agitated, hostile, aggressive, restless, hyperactive (mentally or physically), depressed, or have thoughts about suicide or hurting yourself.

Call your doctor at once if you have:

• weak or shallow breathing;

• blue-coloured skin, lips, fingers, and toes;

• confusion, extreme drowsiness or weakness;

• problems with balance or muscle movement;

• unusual or involuntary eye movements; or

• Increased seizures.

Some side effects are more likely in children taking gabapentin. Contact your doctor if the child taking this medicine has any of the following side effects:

• changes in behaviour;

• memory problems;

• trouble concentrating; or

• acting restless, hostile, or aggressive.

Common Gabapentin side effects may include:

• fever, chills, sore throat, body aches, unusual tiredness;

• jerky movements;

• headache;

• double vision;

• swelling of your legs and feet;

• tremors;

• trouble speaking;

• dizziness, drowsiness, tiredness;

• problems with balance or eye movements; or

• Nausea, vomiting.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.