Gabapentin is used to treat partial and secondarily generalized seizures. Gabapentin does not prevent seizures that begin on both sides of the brain at the same time, called primary generalized seizures.
Gabapentin is usually used as an additional seizure medicine when another medicine has not been able to control all of a person's partial seizures. This kind of use is called add-on or adjunctive therapy. Gabapentin was usually used in this way when it was being tested, so the U.S. Food and Drug Administration (FDA) has only approved it as add-on therapy. Gabapentin is easy to use as an add-on therapy because it does not interact with other seizure medicines.
Rarely gabapentin is also used alone to treat partial seizures.
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 "shingles" (called postherpetic neuralgia).
It is legal (and common) to prescribe medicines for “off-label” uses even though the FDA has not formally approved such uses. So gabapentin is often used off-label for many types of pain, most often the pain of diabetic neuropathy, as well as for some mood disorders, such as anxiety. In fact, more people take gabapentin to treat pain than to control seizures.
Gabapentin is very well tolerated by patients and has few side effects. The most common complaints are usually mild and include:
If these problems do not go away within several days, or are really bothersome, call the doctor, but never stop or reduce the medicine on your own. Sometimes the doctor can help with these side effects by changing the prescription:
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.
Most people who take gabapentin have no or few mild side effects that typically fade within a short period of time. Gabapentin appears to be an exceptionally safe medicine. Indeed, no life-threatening reactions have been linked to it.
It is not unusual for gabapentin to make people feel a bit sleepy or uncoordinated. If you have 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.
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 over-the-counter medicines at the drug store. These interactions between different products are not a concern with gabapentin. There seem to be no medicines, supplements, herbs, or vitamins that affect or are affected by gabapentin in the body 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 the doses of antacid and 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.
Talk to your doctor or another health professional if you are pregnant or plan to become pregnant. There is not yet enough information available to estimate the risk of birth defects if gabapentin is taken during pregnancy. Nor is enough known 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.
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 specific birth defects called Neural Tube Defects. (The most well-known of these is spina bifida, in which the spinal cord is not completely enclosed.) Women with epilepsy should take between 1 and 4 mg of folic acid daily during their reproductive years. If the doctor thinks a woman is at especially high risk, the larger dose of folic acid—4 mg (4000 mcg) per day—may be recommended, beginning before the woman becomes pregnant.
Some babies born to mothers taking antiepileptic medications have had inadequate blood clotting within the first 24 hours after birth. It is often recommended that the mother be given 10 to 20 mg of vitamin K per day during the last month of pregnancy to prevent this problem.
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.
Gabapentin passes nearly completely into breast milk, however how much of this actually enters the baby’s bloodstream is not known. Further, how gabapentin affects the baby is unknown. That said, it is strongly felt by neurologists and epileptologists that the benefits of breastfeeding largely outweigh the risks of exposing the baby to antiepileptic medications, including gabapentin. As a matter of fact, the American Academy of Neurology and the American Epilepsy Society both recommend breastfeeding in women with epilepsy.