Gabapentin belongs to the class of medications called anti-epileptics. It is used for the management and prevention of seizures associated with epilepsy, often in combination with other seizure-control medications. 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.

Your doctor may have suggested this medication for conditions other than the ones 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.

The recommended adult dose of gabapentin usually begins with 300 mg to 400 mg daily and increases to as much as 800 mg three times daily, according to need and as prescribed by doctor. The usual maximum dose is 2,400 mg daily taken in three equally divided doses. Gabapentin may be taken with or without food.

Many things can affect the dose of medication that a person needs, such as the severity of the condition, 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 very important to take this medication exactly as prescribed by your doctor. If you forget a dose of this medication, take it as soon as you remember. If it is less than two hours until your next scheduled dose, take the medication right away and then wait two hours before taking the next dose. Then go back to your regular dosing schedule. Do not take a double dose to make up for a missed one.

Neurontin^® is available as capsules or tablets.

Capsules:
100 mg: Each hard gelatin capsule, with white, opaque body and cap, marked "PD" on one side and "Neurontin/100 mg" on the other, contains gabapentin 100 mg.
300 mg: Each hard gelatin capsule, with yellow, opaque body and cap, marked "PD" on one side and "Neurontin/300 mg" on the other, contains gabapentin 300 mg.
400 mg: Each hard gelatin capsule, with orange, opaque body and cap, marked "PD" on one side and "Neurontin/400 mg" on the other, contains gabapentin 400 mg.
Nonmedicinal ingredients: cornstarch, lactose and talc; capsule shells may contain: FD&C Blue No. 2, gelatin, red iron oxide, silicon dioxide, sodium lauryl sulfate, titanium dioxide, and yellow iron oxide.

Tablets:
600 mg: Each white, elliptical, film-coated tablet, with "Neurontin 600" printed on one side, contains gabapentin 600 mg. Nonmedicinal ingredients: ammonium hydroxide, black iron oxide, candelilla wax, copolyvidone, cornstarch, hydroxypropyl cellulose, magnesium stearate, poloxamer 407 NF, and talc.
800 mg: Each white, elliptical, film-coated tablet, with "Neurontin 800" printed on one side, contains gabapentin 800 mg. Nonmedicinal ingredients: candelilla wax, copolyvidone, cornstarch, hydroypropyl cellulose, hydroxypropyl methylcellulose, magnesium stearate, poloxamer 407 NF, red iron oxide, yellow iron oxide, and talc.

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 health professional. They may be able to help you to deal with some of the effects.

The following side effects may go away as your body becomes used to the medication; check with your doctor if they continue or become bothersome.

More common
• blurred or double vision
• dizziness
• drowsiness
• muscle ache or pain
• swelling of hands, feet, or lower legs
• trembling or shaking
• unusual tiredness or weakness

Less common
• back pain
• constipation
• decrease in sexual desire or ability
• diarrhea
• difficulty sleeping
• difficulty thinking
• dryness of mouth or throat
• frequent urination
• headache
• indigestion
• low blood pressure
• nausea
• noise in ears
• runny nose
• slurred speech
• twitching
• vomiting
• weakness or loss of strength
• weight gain

Contact your doctor as soon as possible if any of the following side effects occur:

More common
• clumsiness or unsteadiness
• continuous, uncontrolled, back-and-forth or rolling eye movements

More common (in children 3 to 12 years of age)
• aggressive behaviour or other behaviour problems
• anxiety
• concentration problems and change in school performance
• crying
• false sense of well-being
• hyperactivity or increase in body movements
• overreacting or reacting too quickly or too emotionally
• rapidly changing moods
• restlessness
• suspiciousness or distrust

Less common
• depression, irritability, or other mood or mental changes
• loss of memory

Rare
• cough or hoarseness
• fever or chills
• lower back or side pain
• painful or difficult urination

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.

Kidney function: Gabapentin is not removed from the body as quickly in people with reduced kidney function, and so the doctor may have to reduce the dose.

Occupational hazards: People with uncontrolled epilepsy should not drive or handle potentially dangerous machinery. Those taking gabapentin should not undertake activities requiring mental alertness or physical coordination until they determine that gabapentin does not affect them adversely.

Stopping the medication: As with other medications used to control seizures, stopping gabapentin suddenly is not recommended because of the possibility of increased seizure frequency.

Pregnancy: Only use this medication during pregnancy if the potential benefit justifies the potential risk. Talk to your doctor if you are or may be pregnant.

Breast-feeding: It is not known if gabapentin passes into breast milk, and the effect on the nursing infant is unknown. Breast-feeding while taking this medication is only recommended if the potential benefit outweighs the potential risks. If you are nursing, talk to your doctor.

Children: The safety and efficacy of gabapentin have not been established for use by children.

Antacids containing magnesium or aluminum may affect the way that gabapentin works or increase the risk of side effects.

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. In many cases, interactions are intended or are managed by close monitoring. 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 that 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.