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Gabapentin (gab-ah-PEN-tin) is the generic name (non-brand name) of the seizure medicine Neurontin (nur-ON-tin) used in the United States, Canada, the UK, and some other countries. Another commonly used name for gabapentin is GBP.

Gabapentin is manufactured in the United States by Pfizer Inc. through a subsidiary called Greenstone Ltd. It is also manufactured by IVAX and Alpharma. The name or appearance of gabapentin may be different in various countries but usually the dose (measured in milligrams, abbreviated "mg") will be the same.

Neurontin
Tablet
Neurotonin 100mg Capsule

Capsules

100-mg (white, hard-gelatin) Capsules with "PD" on one half and "Neurontin 100 mg" on the other.

Neurotonin 300mg Capsule

300-mg (yellow, hard-gelatin) Capsules with "PD" on one half and "Neurontin 300 mg" on the other.

Neurotonin 400mg Capsule

400-mg (orange, hard-gelatin) Capsules with "PD" on one half and "Neurontin 400 mg" on the other.

Tablets
600-mg (white, oval, coated)
Scored tablet marked with "NT" and "16" on one side

800-mg (white, oval, coated) 
Scored tablet marked with "NT" and "26" on one side

Liquid Solution

250 mg/5 mL (clear, colorless to slightly yellow)
Liquid with strawberry-anise flavor.

Used to Treat

  • Complex Partial Seizures
  • Simple Partial Seizures

Forms

Neurontin is sold in the United States by Pfizer Inc. The name or appearance may be different in various countries but usually the dose (measured in milligrams, abbreviated "mg") will be the same. These descriptions apply to the U.S. versions:

How to Take and Store

See package insert.

How to take and store Gabapentin?

Swallow the capsules or tablets whole.

It's OK to take gabapentin either with food or without food, but it’s best to be consistent day after day.

Don't take an antacid (like Maalox) within 2 hours of taking gabapentin. Antacids can prevent your body from absorbing all the gabapentin.

As the doctor increases the amount of gabapentin that you take, you may be given a different kind of pill than the ones you've been taking. Be careful! For example, if you've been using 300-mg capsules and the new prescription is for 600-mg tablets, be sure to take the right number. Don't automatically continue to take the same number of pills as before.

Don't take more than the doctor prescribes. If you think you've used an extra pill call your doctor for advice. For a larger overdose, call your local poison control center or emergency room right away, unless you have special instructions from the doctor.

Don't stop taking gabapentin or change the amount you use without talking to the doctor first. Stopping any seizure medicine all at once can cause serious problems.

Store the capsules or tablets at room temperature, away from dampness and direct light. (Don't keep them in the bathroom if it's damp there.) Of course, keep all gabapentin out of the reach of children.

What if I forget?

In general, if you forget a dose, take it as soon as you remember. If it is almost time for the next dose, delay that dose for a few hours, instead of taking two doses very close together. Then go back to the regular schedule. If you're not sure about what to do, call the doctor's office for more advice.

Do your best to follow the doctor's directions. The more often a medicine must be taken, the greater the chance of forgetting, and most people need to take gabapentin 3 times every day. This can be difficult. If you forget doses often, it may be a good idea to get a special pillbox or watch with an alarm to remind you.

Taking the right amount of seizure medicine on time every single day is the most important step in preventing seizures!

How does Gabapentin effect the brain?

Brain cells need to work (fire) at a certain rate to function normally. During a seizure, brain cells are forced to work much more rapidly than normal. Gabapentin helps prevent brain cells from working as fast as a seizure requires them to. In this way, seizures can be stopped when they are just beginning.

We don't completely understand how gabapentin works in the brain to stop seizures. It probably causes brain cells to make more of a chemical (called GABA) that stops brain cells from firing.

How does the body digest Gabapentin?

After medicine is swallowed, it must be absorbed into the blood so it can move throughout the body. The process of absorbing a medicine or food, digesting it, and eliminating it from the body is called metabolism. The way the body metabolizes a particular medicine affects how often it must be taken. It also determines whether it will interact with other medicines or be affected by conditions such as disease of the liver or kidneys.

Many other medicines are metabolized by the liver, but Gabapentin is not. This is why it does not affect the way other medicines work, and they do not affect gabapentin. People with liver disease should be able to use it without trouble.

The body removes gabapentin through the kidneys, so people with kidney disorders need to be careful. To prevent too much gabapentin from building up in the body, they usually need to take less gabapentin and take it less often.

How well does the Gabapentin work?

Doctors have studied large numbers of people with epilepsy to find out how well gabapentin controls seizures. When it was used as an add-on with another seizure medicine, a number of adults had large reductions in their seizures, and side effects were not much trouble.

A similar study in children aged 3 to 12 years had similar results. The children with complex partial seizures and secondarily generalized seizures showed the greatest improvement.

Gabapentin is not the best add-on seizure medicine for everyone. Sometimes, a series of combinations must be tried before finding what is best for the individual. Gabapentin does have an advantage over some other medicines used for add-on therapy, because the doctor won't have to change how much of the first medicine is prescribed. The lack of interactions also makes gabapentin a good choice for people who need to take medicines for other disorders.

Some research also has looked at how well gabapentin works to control seizures when it is used alone. In one study, people with newly diagnosed partial seizures were treated with either gabapentin or another commonly used seizure medicine, carbamazepine (Tegretol, Carbatrol). The two medicines had just about the same effect on the seizures, but fewer people taking gabapentin had very troublesome side effects.

What are the most common side effects of Gabapentin?

Most people who take gabapentin don't have too much trouble with side effects. The most common complaints (usually not too severe) are:

  • tiredness
  • sleepiness
  • dizziness
  • weight gain
  • ankle swelling

If you notice any of these problems, call the doctor. Sometimes the doctor can help by changing the amount of gabapentin prescribed or when you take it. Don't stop taking gabapentin or change the amount you take without your doctor's guidance.

Some people who take gabapentin actually feel that their mood and sense of well-being is improved. Doctors are exploring whether it can be used to treat disorders like depression and anxiety.

People who have just started taking gabapentin (or who have just started taking a larger amount) should be careful during activities that might be dangerous, until they know whether they are having any side effects.

Allergic reactions

There do not appear to be any allergic reactions to gabapentin.

Long-term side effects

The long-term side effects of gabapentin are not known.

What are the most serious side effects of Gabapentin?

Most people who take gabapentin have mild side effects that go away with no lasting harm, or even no side effects at all. Gabapentin appears to be an exceptionally safe medicine. Indeed, no life-threatening reactions have been linked to it.

It is important to remember that only a tiny number of people who take gabapentin have any serious problems. Tell the doctor right away if you notice anything that worries you, but don't stop using the gabapentin unless the doctor says so.

Remember that it's not unusual for gabapentin to make people feel a bit sleepy or uncoordinated. If you've just started taking gabapentin or have just had your dosage increased, be careful when doing things that could be dangerous (like driving or operating machinery) until you know how it will affect you. Be particularly cautious if you tend to be sensitive to medications.

On July 10, 2008, an advisory panel was convened by the Food and Drug Administration (FDA) to review data that the FDA had previously collected from drug studies showing an association between many of the antiepileptic drugs (AEDs) and suicidal ideation and behavior, which together are called suicidality. According to the FDA’s Alert, among the patients with epilepsy in these drug studies, 1 out of 1000 people taking the placebo (inactive substance) showed suicidality compared to approximately 3.5 out of 1000 people who took an AED. The FDA advisory panel voted to accept the FDA's data at its meeting on July 10. The FDA has provided the following information for patients, family members, and caregivers at http://www.fda.gov/Drugs/DrugSafety/PostmarketDrugSafetyInformationforPatientsandProviders/ucm100192.htm.

Taking antiepileptic medicines may increase the risk of having suicidal thoughts or actions;

  • Do not make any changes to the medication regimen without first talking with the responsible healthcare professional;
  • Pay close attention to any day-to-day changes in mood, behavior and actions. These changes can happen very quickly so it is important to be mindful of any sudden differences.

Be aware of common warning signs that might be a signal for risk of suicide. Some of these are:

  •  Talking or thinking about wanting to hurt yourself or end your life
  •  Withdrawing from friends and family
  •  Becoming depressed or having your depression get worse
  •  Becoming preoccupied with death and dying
  •  Giving away prized possessions

We again urge patients and families to contact their doctor before stopping an epilepsy medication because this may possibly lead to seizures and worsening of mood.

Impact of Gabapentin on bone health

At this time there is no evidence to support that Gabapentin causes bone health problems.  Please see package insert.

What else is Gabapentin used for?

Besides controlling seizures, gabapentin is also helpful for some kinds of pain. It has been approved by the Food and Drug Administration (FDA) to treat pain that follows the "shingles" (called postherpetic neuralgia).

It is legal (and common) to prescribe medicines for so-called off-label uses even though the FDA has not formally approved such use. So gabapentin is often used "off-label" for many types of pain as well as for some mood disorders, such as anxiety. In fact, more people have taken gabapentin to treat pain than to control seizures.

Who should not take Gabapentin?

Gabapentin sometimes worsens absence and myoclonic seizures. People who have seizures of these types should not use it.

Also, people who are allergic to any of the ingredients in gabapentin should not take it.

Can Gabapentin be taken with other medicines?

Sometimes one kind of medicine changes the way another kind of medicine works in the body. This is true not only for prescription medicines, but also for medicines you just pick up off the shelf at the store. It’s also true for herbal products, vitamins, a few kinds of food, and sometimes even cigarettes!

These interactions between different products are not a concern with gabapentin. There seem to be no medicines, supplements, herbs, or vitamins that affect gabapentin in the body, and Gabapentin does not affect any other medicines or other products.

One exception is that some antacids, such as Maalox, interfere with the way the body absorbs gabapentin. This problem can be avoided if you wait at least 2 hours between doses of antacid and gabapentin.

What are the effects of Gabapentin on Children?

Gabapentin is useful in treating partial seizures in children. But absence seizures, which are also common, can be made worse, so a correct diagnosis is very important.

To keep side effects at a minimum, the doctor probably will prescribe a low dose of gabapentin to start and increase it slowly. It is usually given in 3 equal doses.

Parents and doctors need to watch for problems with behavior, emotions, or concentration in children. These problems are uncommon, but if they occur they can interfere with the child’s development and school performance.

If a woman takes Gabapentin during pregnancy will it hurt the baby?

In the United States, the Food and Drug Administration (FDA) assigns each medication to a Pregnancy Category according to whether it has been proven to be harmful in pregnancy. gabapentin is listed in Pregnancy Category C. This indicates that caution is advised, but the benefits of the medicine may outweigh the potential risks. Studies in animals have shown some harm to the baby, but there haven't been any good studies of results in women.

Talk to your doctor or another health professional if you are pregnant or plan to become pregnant. We don't yet have enough information to be able to estimate the risk of various types of birth defects that might occur if gabapentin is taken during pregnancy. We also don't know enough to compare the risk with gabapentin to the risk with other seizure medicines.

In general, the risk of defects is higher for women who take more than one seizure medicine and for women with a family history of birth defects. Whether this applies to gabapentin is not yet known.

All women who are capable of becoming pregnant should take at least 0.4 mg (400 mcg) of the vitamin called folic acid every day because it helps to prevent one type of birth defect. (The most well-known of these is spina bifida, in which the spinal cord is not completely enclosed.) If the doctor thinks a woman is at especially high risk, a much larger dose of folic acid—4 mg (4000 mcg) per day—may be recommended.

About 20% to 35% of women have seizures more often during pregnancy because of changes in hormones or changes in how their seizure medicine is handled by the body. Even though this may not apply to gabapentin, the doctor may recommend checking the level of medication in the blood regularly during pregnancy so that the dosage can be adjusted as needed.

During breast-feeding, a small amount of the gabapentin will appear in the milk. The effect of this amount on an infant is unknown. If you are taking gabapentin and want to breast-feed your baby, check with your doctor about what seizure medicine would be best for you.

What are the effects of Gabapentin on Seniors

Doctors have prescribed gabapentin for many people over 65 with good results. Many of these prescriptions are to treat conditions other than epilepsy, and some are prescribed for seniors who have experienced only one seizure.

Because gabapentin generally does not interact with other medicines, it can be a good choice for seniors who also are being treated for other disorders. One exception is that antacids like Maalox reduce the absorption of gabapentin and should not be used within 2 hours of a dose of gabapentin.

Seniors also tend to be more sensitive than younger adults to medicines and their side effects. For instance, many seniors have a problem with sleepiness or poor coordination even before they start taking gabapentin. These are common side effects of this medicine, so these problems may become worse and cause real trouble.

Seniors also face more danger from these side effects because they are more likely to be seriously hurt if they fall or have another kind of accident.

To reduce side effects, the doctor probably will prescribe a low dose of gabapentin to start and then be very cautious about any increases. It’s especially important for seniors to keep the doctor informed about any changes that they notice.

What are the dose ranges for Gabapentin?

The best amount is the amount that completely controls seizures without causing troublesome side effects. It depends on many factors, which are different for every individual. Follow the doctor's directions. Call if you have any questions.

No one should stop taking gabapentin or change the amount they take without talking to the doctor first. Stopping any seizure medicine all at once can cause a problem that may be life-threatening.

Don’t use more than the doctor prescribes. If a little extra (such as an extra pill) is taken by accident, call the doctor for advice. For a larger overdose, call a poison control center or emergency room right away unless you have other specific directions from your doctor.

To avoid unwanted side effects, the doctor will prescribe a low dose to start and increase it gradually. People over 12 years of age usually start by taking 300 milligrams (mg) per day. The doctor gradually prescribes more until their seizures are controlled. Most people need to take gabapentin 3 times a day.

Seniors usually need less gabapentin and should take it less often.

Special Concerns for Gabapentin

See package insert.

Read the package insert of Gabapentin

In the United States, companies that manufacture medicines are required to publish certain kinds of information about each product. This document is commonly known as a “package insert” because it is usually included with each package of the medicine.

You can also read these documents (also called "prescribing information") online. The U.S. package insert for Neurontin (gabapentin) is found at:

Some of the information may differ in other countries.

To learn how to read and understand a package insert, see How to read a package insert.