Controlling Epilepsy : Drug Treatment, Pregnancy Risk

by Food and Drug Administration (FDA)

(Page 2 of 3)

Drug Treatment

Drugs, surgery, a special diet, or a combination of these treatments is used to prevent seizures. Drug therapy alone can control seizures in about three-quarters of all people with epilepsy.

FDA has approved 16 drugs to treat epilepsy. The most commonly prescribed epilepsy drugs are carbamazepine (Tegretol), clonazepam (Clonopin), phenytoin (Dilantin), valproic acid (Depakene or Depakote), phenobarbital, primidone (Mysoline), and ethosuximide (Zarontin). Seizures can usually be controlled with one drug, although, rarely, patients may have to take more than one.

Researchers have yet to pinpoint exactly how most epilepsy drugs prevent seizures. Some epilepsy drugs appear to prevent seizures by boosting the amount or actions of certain brain compounds, called neurotransmitters, that inhibit the transfer of electrical impulses from neuron to neuron. Others may influence the passage of electrically charged atoms (ions) through the neuron membrane. These ions trigger the firing of neurons.

Many epilepsy drugs cause unwanted side effects, such as drowsiness, confusion, clumsiness, nausea, increased appetite, and behavioral or learning problems. These side effects can often be relieved by adjusting the dosage or by switching to a different drug.

To find the appropriate dose of medication, doctors usually take frequent blood samples to measure the amount of drug circulating in the patient's bloodstream. The blood levels are monitored at various drug dosages until the dose that best controls seizures with the fewest side effects is determined. Monitoring can take from a week to several months to establish the optimum dose of the appropriate medicine for a given patient. Children and pregnant women need to continue to have their dosages adjusted.

Pregnancy Risk

Women taking epilepsy medication during pregnancy have about two to three times the standard risk of bearing a child with birth defects. Nevertheless, at least 90 percent of women who take epilepsy drugs during pregnancy give birth to normal, healthy infants. A seizure during pregnancy carries its own risks. The fetus may be deprived of oxygen due to the mother's impaired breathing during a seizure, for example, or both mother and child may be injured from a seizure-induced fall. Therefore, most doctors advise pregnant women with epilepsy to continue taking their medication unless it is likely that a woman will be seizure-free without it.

Many epilepsy drugs are excreted in breast milk, but usually in such small amounts that they are unlikely to affect the infant. Most physicians recommend that women with epilepsy breast-feed their newborns, although they may suggest alternating breast- and bottle-feeding to lower the infant's exposure to medication.

Drug Interactions

Several drugs interact with some kinds of epilepsy medicine, lessening or intensifying the effects of one or the other drug. To avoid such drug interactions, patients should tell their doctors about any other medications they are taking whenever a new drug is prescribed. Similarly, patients taking an epilepsy drug should check with the pharmacist about possible interactions with over-the-counter drugs they purchase. Birth control pills, the antibiotic erythromycin, some types of asthma, ulcer or heart medicines, and alcohol are known to interact with certain epilepsy drugs.

People taking epilepsy drugs should not change the dose or stop a medication without first consulting a doctor. Suddenly stopping epilepsy medicines can prompt a series of seizures that can be fatal.

Most epilepsy medicines need to be stored in a dry place because any moisture that seeps into the drugs can dramatically alter the medicine's strength. "In general, you shouldn't keep epilepsy drugs on a bathroom shelf where they might be exposed to steam from showers," says Russell Katz, M.D., deputy director of FDA's division of neuropharmacological drug products.

Epilepsy drugs are taken daily by mouth for a period of years or, for some patients, a lifetime. Recent research reveals that when epilepsy drugs are slowly withdrawn after a person has been free of seizures for a few years, most people can stay free of seizures without medication. This is especially true for children. On the other hand, people with certain forms of epilepsy, such as those that cause partial or mixed seizure types, are less likely to be seizure-free after stopping medication.

If drugs cannot control a person's seizures, a doctor may prescribe a ketogenic diet. This high-fat diet produces a chemical condition in the body called ketosis, which in some people, particularly children, prevents seizures. Most people find the ketogenic diet hard to swallow, however, because it makes them nauseous and is expensive and difficult to administer. Moreover, the diet often doesn't work, according to Porter.

About the Author

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FDA is A United States government body that oversees medical devices, including contact lenses, intraocular lenses, excimer lasers and eyedrops. In the US, these products must be approved by the FDA before they can be marketed.