Anticonvulsants may be needed to reduce the risk of having another seizure. Anticonvulsants are not usually prescribed for people who have had only one generalized seizure for which no cause can be found. But they are necessary for people who have had more than one, unless the cause has been identified and completely eliminated.

Anticonvulsants can completely prevent convulsive seizures in more than half of the people who have them and greatly reduce the frequency of seizures in another third. These drugs are only slightly less effective for absence seizures. Half of the people who respond to anticonvulsants can eventually discontinue them without having a relapse. However, for about 10 to 20% of people with a seizure disorder, anticonvulsants do not adequately prevent seizures.

No one drug can control all types of seizures. For most people, seizures can be controlled with a single drug. If seizures recur, different anticonvulsants are tried. Determining which anticonvulsant is effective may take several months. Some people have to take several drugs.

For women who have a seizure disorder and are pregnant, taking an anticonvulsant increases the risk of miscarrying or of having a baby with a birth defect (see Some Drugs That Can Cause Problems During Pregnancy*). However, stopping the anticonvulsant may be more harmful to the woman and the baby.

Because status epilepticus is an emergency, large intravenous doses of one or more anticonvulsants are given as quickly as possible. Measures to prevent injuries are taken during the prolonged seizure.

Anticonvulsants, though very effective, may have side effects. Many cause drowsiness but, paradoxically, sometimes cause hyperactivity in children. Blood tests are performed periodically to determine whether an anticonvulsant is affecting the kidneys, liver, or blood cells. People taking anticonvulsants should be aware of possible side effects and should consult their doctor at the first sign of side effects.

The dose of an anticonvulsant is critical: The best dose of an anticonvulsant is the smallest dose that stops all seizures while causing the fewest side effects. Doctors ask the person about side effects, then adjust the dose if needed. Sometimes doctors also measure the level of anticonvulsant in the blood. Anticonvulsants should be taken just as prescribed. No other drugs should be taken at the same time without the doctor's or pharmacist's authorization because many drugs alter the level of anticonvulsant in the blood. People who take anticonvulsants should see a doctor regularly for dose adjustment and should always wear a Medic Alert bracelet inscribed with the type of seizure disorder and the drug being taken.

Exercise is recommended and social activities are encouraged. However, people who have a seizure disorder may have to make some adjustments. For example, they should not drink alcoholic beverages. They should not engage in activities where a sudden loss of consciousness could result in serious injury: They should not swim alone or operate power tools. In most states, laws prohibit people with a seizure disorder from driving until they have been free of seizures for at least 6 months to 1 year.

A family member or close friend should be trained to help if a seizure occurs. Attempting to put an object (such as a spoon) in the person's mouth to protect the person's tongue should not be tried, because such efforts can do more harm than good. The teeth may be damaged, or the person may bite the helper unintentionally as the jaw muscles contract. The important steps are protecting the person from falling, loosening clothing around the neck, and placing a pillow under the head. People who lose consciousness should be rolled onto one side to ease breathing. People who have had a seizure should not be left alone until they have awakened completely and can move about normally. Usually, their doctor should be notified.

If all drugs are ineffective in controlling seizures or if side effects of the drug cannot be tolerated, brain surgery is a possibility. If a defect in the brain (such as a scar) can be identified as the cause and is confined to a small area, surgically removing that area may eliminate the seizures or reduce their severity and frequency. Surgically cutting the nerve fibers that connect the two sides of the brain (corpus callosum) may help people who have seizures that originate in several areas of the brain or that spread to all parts of the brain very quickly. This procedure usually has no appreciable side effects. After surgery, many people need to continue to take anticonvulsants.

Electrical stimulation of the vagus nerve (cranial nerve X) can reduce the number of partial seizures by one third. The vagus nerve is thought to have indirect connections to areas of the brain often involved in producing seizures. A device that looks like a heart pacemaker is implanted under the left collarbone and is connected to the vagus nerve in the neck with a wire that runs under the skin. The device causes a small bulge under the skin. The operation is performed on an outpatient basis and takes about 1 to 2 hours. When people who have such a device sense that a seizure is about to begin, they turn the device on with a magnet. Or, the device may be left on all the time. For some people, vagus nerve stimulation prevents seizures or reduces their frequency and severity. Vagus nerve stimulation is used in addition to anticonvulsants. Side effects include hoarseness, cough, and deepening of the voice.