How does this medication work? What will it do for me?

Gabapentin belongs to the class of medications called anti-epileptics. It is used in combination with other seizure control medications for the management and prevention of seizures associated with epilepsy. Gabapentin does not cure epilepsy and only works to control seizures as long as the medication is taken. Gabapentin works by affecting the transmission of nerve signals in the brain.

This medication may be available under multiple brand names and/or in several different forms. Any specific brand name of this medication may not be available in all of the forms or approved for all of the conditions discussed here. As well, some forms of this medication may not be used for all of the conditions discussed here.

Your doctor may have suggested this medication for conditions other than those listed in these drug information articles. If you have not discussed this with your doctor or are not sure why you are taking this medication, speak to your doctor. Do not stop taking this medication without consulting your doctor.

Do not give this medication to anyone else, even if they have the same symptoms as you do. It can be harmful for people to take this medication if their doctor has not prescribed it.

What form(s) does this medication come in?


100 mg
Each capsule with white opaque body and cap, imprinted "Gabapentin / 100 mg" on the cap in blue ink, contains gabapentin 100 mg. Nonmedicinal ingredients: corn starch, lactose, and talc; capsule shell: gelatin and titanium dioxide.

300 mg
Each capsule with yellow opaque body and cap, imprinted "Gabapentin / 300 mg" on the cap in blue ink, contains gabapentin 300 mg. Nonmedicinal ingredients: corn starch, lactose, and talc;  capsule shell: gelatin, titanium dioxide, and yellow iron oxide.

400 mg
Each capsule with orange opaque body and cap, imprinted "Gabapentin / 400 mg" on cap in blue ink, contains gabapentin 400 mg. Nonmedicinal ingredients: corn starch, lactose, and talc; capsule shell: gelatin, titanium dioxide, red iron oxide, and yellow iron oxide.


600 mg
Each white-to-off-white, elliptical, film-coated tablet, imprinted "N" on one side and "600" on the other, contains gabapentin 600 mg. Nonmedicinal ingredients: povidone, microcrystalline cellulose, crospovidone, talc, hydrogenated vegetable oil, black iron oxide (ink); film coating: polyvinyl alcohol, titanium dioxide, macrogol and talc.

800 mg
Each white-to-off-white, elliptical, film-coated tablet, imprinted "N" on one side and "800" on the other, contains gabapentin 800 mg. Nonmedicinal ingredients: povidone, microcrystalline cellulose, crospovidone, talc, hydrogenated vegetable oil; film coating: polyvinyl alcohol-part hydrolysed, titanium dioxide, polyethylene glycol, and talc.

How should I use this medication?

The usual recommended adult dose of gabapentin begins with 300 mg 3 times daily and increases to as much as 600 mg 3 times daily, according to individual need and as prescribed by the doctor. The usual maximum daily dose is 2,400 mg taken in 3 equal doses of 800 mg each.

Gabapentin may be taken with or without food.

Many things can affect the dose of medication that a person needs, such as body weight, other medical conditions, and other medications. If your doctor has recommended a dose different from the ones listed here, do not change the way that you are taking the medication without consulting your doctor.

It is important that this medication be taken exactly as prescribed by your doctor. If you miss a dose, take it as soon as possible and continue with your regular schedule. If it is less than 4 hours until your next scheduled dose, skip the missed dose and continue with your regular dosing schedule. Do not take a double dose to make up for a missed one. If you are not sure what to do after missing a dose, contact your doctor or pharmacist for advice.

Store this medication at room temperature and keep it out of the reach of children.

Do not dispose of medications in wastewater (e.g. down the sink or in the toilet) or in household garbage. Ask your pharmacist how to dispose of medications that are no longer needed or have expired.

Who should NOT take this medication?

Do not take gabapentin if you are allergic to gabapentin or any ingredients of this medication.

What side effects are possible with this medication?

Many medications can cause side effects. A side effect is an unwanted response to a medication when it is taken in normal doses. Side effects can be mild or severe, temporary or permanent.

The side effects listed below are not experienced by everyone who takes this medication. If you are concerned about side effects, discuss the risks and benefits of this medication with your doctor.

The following side effects have been reported by at least 1% of people taking this medication. Many of these side effects can be managed, and some may go away on their own over time.

Contact your doctor if you experience these side effects and they are severe or bothersome. Your pharmacist may be able to advise you on managing side effects.

  • back pain
  • constipation
  • coughing
  • dizziness
  • drowsiness
  • dry mouth
  • erectile difficulties (problems getting or maintaining an erection sufficient for sexual intercourse)
  • fatigue
  • headache
  • heartburn
  • increased appetite
  • itchy skin
  • muscle pain
  • nervousness
  • runny nose
  • sore throat
  • swelling of feet or ankles
  • tremors (shaking)
  • twitching
  • weight gain

Although most of the side effects listed below don't happen very often, they could lead to serious problems if you do not check with your doctor or seek medical attention.
Check with your doctor as soon as possible if any of the following side effects occur:

  • abnormal heartbeat or heart palpitations
  • abnormal thoughts
  • involuntary eye movements, double vision, or other vision changes
  • poor coordination
  • problems with your teeth or gums
  • shortness of breath
  • speech problems such as slurred speech; abnormal rhythm, speed, or tone (such as sounding hoarse or "nasal") of speech; limited mouth or tongue movements; or drooling
  • signs of depression (e.g., poor concentration, changes in weight, changes in sleep, decreased interest in activities, thoughts of suicide)
  • signs of infection (symptoms may include fever or chills, severe diarrhea, shortness of breath, prolonged dizziness, headache, stiff neck, weight loss, or listlessness)
  • symptoms of liver problems (e.g., abdominal pain, persistent vomiting, feeling unwell, fever, itching, yellowing of the skin and eyes, dark urine)

Stop taking the medication and seek immediate medical attention if any of the following occur:

  • hallucinations
  • signs of a serious allergic reaction (e.g., swelling of face or throat, hives, or difficulty breathing)
Some people may experience side effects other than those listed. Check with your doctor if you notice any symptom that worries you while you are taking this medication.

Are there any other precautions or warnings for this medication?

Before you begin using a medication, be sure to inform your doctor of any medical conditions or allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should use this medication.

Alcohol: Avoid alcohol while taking gabapentin, as gabapentin may cause alcohol intolerance that leads to an unpleasant reaction after drinking alcohol, such as flushing, redness of the face after drinking alcohol, nausea, palpitations, or headache.

Diabetes: Gabapentin may affect blood sugar levels. If you have diabetes, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Drowsiness/reduced alertness: If you have uncontrolled epilepsy, do not drive or handle potentially dangerous machinery. Gabapentin may cause drowsiness, dizziness, or problems with coordination. Avoid any activity requiring mental alertness or physical coordination until you determine that gabapentin does not affect you in this way.

Kidney function: Gabapentin is not removed from the body as quickly in people with reduced kidney function as compared with those who have regular kidney function. Your doctor may reduce your dose as needed.

Stopping the medication: As with other medications used to control seizures, stopping gabapentin suddenly could increase the risk of seizures. Do not stop gabapentin suddenly. Ask your doctor how to safely and gradually stop the medication.

Suicidal or agitated behaviour: People taking this medication may feel agitated (restless, anxious, aggressive, emotional, and feeling not like themselves), or they may want to hurt themselves or others. If you experience these side effects or notice them in a family member who is taking this medication, contact your doctor immediately. You should be closely monitored by your doctor for emotional and behaviour changes while taking this medication.

Pregnancy: This medication should not be used during pregnancy unless the benefits outweigh the risks. If you become pregnant while taking this medication, contact your doctor immediately.

Breast-feeding: This medication passes into breast milk. If you are a breast-feeding mother and are taking gabapentin, it may affect your baby. Talk to your doctor about whether you should continue breast-feeding.

Children: The safety and effectiveness of using this medication have not been established for children.

What other drugs could interact with this medication?

There may be an interaction between gabapentin and any of the following:

  • antacids containing magnesium or aluminum
  • cimetidine
  • mefloquine
  • narcotic pain relievers (e.g., codeine, hydrocodone,  morphine, oxycodone)
  • other medications which cause drowsiness
  • sodium bicarbonate
  • tapentadol

If you are taking any of these medications, speak with your doctor or pharmacist. Depending on your specific circumstances, your doctor may want you to:

  • stop taking one of the medications,
  • change one of the medications to another,
  • change how you are taking one or both of the medications, or
  • leave everything as is.

An interaction between two medications does not always mean that you must stop taking one of them. Speak to your doctor about how any drug interactions are being managed or should be managed.

Medications other than those listed above may interact with this medication. Tell your doctor or prescriber about all prescription, over-the-counter (non-prescription), and herbal medications you are taking. Also tell them about any supplements you take. Since caffeine, alcohol, the nicotine from cigarettes, or street drugs can affect the action of many medications, you should let your prescriber know if you use them.