Anti-Epileptic Drugs (AEDs)
What are AEDs?
Medicines known as antiepileptic drugs (AEDs) help control the frequency and severity of seizures. There are several AEDs available, because each works in different ways and has proven effective for certain types of epilepsy. While one medicine may be helpful in controlling partial seizures, it may make another type of seizure worse. When doctors prescribe an AED, therefore, many factors are taken into account including: the patients age and gender; seizure type (which can be determined with an EEG); and medical history. For the medication to work most effectively, the patient must take it according to the doctors directions. Periodic blood tests measure the amount of AED in the blood; these blood levels can help determine whether the patient is receiving too much or too little of the drug, or even if another medication is needed to control seizures.
While generic drug substitutions may be acceptable for other medical conditions, people with epilepsy should check with their doctor first before accepting a generic AED. Generic drugs cost less, but the therapeutic range between "brand" and generic AEDs may be too broad, causing a loss of seizure control.
Types of AEDs
The family of antiepileptic drugs (AEDs) includes medications that have been used for decades in the treatment of epilepsy, as well as newer therapies. A brief description of some of these medicines and their potential side effects appears below. The side effects listed are in addition to the fatigue, sedation, and cognitive impairment that can occur with many seizure medicines.
Depakote (valproic acid): Depakote is used to treat patients with multiple seizure types, absence seizures, myoclonic epilepsy, and generalized epilepsy. This medicine comes in tablets and as a powder that can be sprinkled on foods.
Side Effects: loss of appetite when beginning the drug; slight hand tremor; anemia; decrease in blood platelet count; liver inflammation.
Dilantin (phenytoin): One of the older AEDs, Dilantin is prescribed for patients with generalized tonic clonic or complex partial seizures. The drugs once-a-day dosage enhances patient compliance.
Side Effects: gingival hyperplasia (gum irritation); swollen lymph glands; rash; excess facial hair growth; thickening of facial skin; liver inflammation.
Gabitril (tiagabine hydrochloride): Gabitril is used as an adjunctive treatment of partial seizures. It increases the activity of gamma aminobutyric acid (GABA), the major inhibitory neurotransmitter in the central nervous system.
Side Effects: dizziness; lack of energy; nausea; tremor; nervousness/irritability; reduced ability to concentrate.
Lamictal (lamotrigine): This medication is used to treat patients with complex partial seizures. If Depakote and Lamictal are used together, Depakote decreases the rate at which the body uses Lamictal. This makes the Lamictal level two to three times higher than if used alone.
Side Effects: dizziness; headache; skin rash; blurred/double vision.
Mysoline (primidone): Mysoline is prescribed for patients with complex partial seizures. Once in the body, it breaks down into pema (an active anticonvulsant) and Phenobarbital (a barbiturate).
Side Effects: drowsiness and hyperirritability (due to the Phenobarbital); vertigo (tends to decrease over time); nausea; impotence; skin rash.
Phenobarbital: Phenobarbital can be prescribed for patients with generalized seizures, but it often is used only after other (AEDs) have been tried.
Side Effects: irritability; hyperactivity; drowsiness; impotence.
Tegretol (carbamazephine): This medicine is effective in controlling partial seizures and primary generalized clonic tonic seizures. Unlike many other AEDs, Tegretol has little effect on cognitive or general functioning.
Side Effects: nausea, dizziness, drowsiness, and unsteadiness when first beginning this medication (these symptoms usually go away over time; it is helpful to take Tegretol on a full stomach); headache and double vision at high doses; aplastic anemia.
Topamax (topiramate): One of the newer AEDs, Topamax is used as an adjunctive treatment of complex partial seizures. It can be taken with or without food, but patients should drink plenty of fluids while taking Topamax to avoid the formation of kidney stones.
Side Effects: drowsiness, tingling in the hands or feet, kidney stones, jerky eye movements.
When Can a Patient Stop Taking an AED?
When people do not have seizures for a long period of time, understandably, they want to stop taking the prescribed antiepileptic drug. However, patients should not stop taking their AED without the permission of their doctor.
Patients who have been seizure-free for many years; are taking only one AED; have a normal EEG; and have no neurological or developmental problems are considered to be good candidates for AED withdrawal. The decision rests with the doctor and the patient, and the risk remains that once the AED is stopped, seizures may re-occur.