Many newer anti-epilepsy drugs (AEDs) are better tolerated than the older, standard AEDs. They often cause less sedation and require less monitoring. Although they are generally approved for use as add-ons to standard drugs that fail to control seizures, they are often prescribed as single drugs. Specific choices usually depend on the individual's particular condition and the specific side effects of the AED. None has emerged as being superior to either standard or newer drugs. All appear to offer some benefits, but, as with standard antiseizure drugs, they also have troublesome side effects.
All antiepileptic drugs can increase the risks of suicidal thoughts and behavior. Research has shown that the highest risk of suicide can occur as soon as 1 week after beginning drug treatment and can continue for at least 24 weeks. Patients who take these drugs should be monitored for signs of suicidality.
Valproate (Depakene, valproic acid) and its delayed release form, divalproex sodium (Depakote), are anticonvulsants. Valproate is the most widely prescribed anti-epileptic drug worldwide.
Uses. Valproate is the first choice for patients with generalized seizures and is used to prevent nearly all other major seizures as well.
General Side Effects. These drugs have a number of side effects that vary depending on dosage and duration. Most side effects occur early in therapy and then subside. General side effects include:
Symptoms of Toxic Side Effects in Liver or Pancreas.
Carbamazepine (Tegretol, Equetro, Carbatrol) is an effective anticonvulsant and specific analgesic when used alone or with other drugs. Carbamazepine also has the added benefit of relieving depression and improving alertness. An extended release form is available that allows twice-daily dosing rather than 3 times a day. A chewable form makes it easier for children to take.
Uses. This drug is used to prevent the following seizures or epilepsy syndromes:
Side Effects. Different side effects may develop or resolve at different points in the treatment duration. Initial side effects may include:
Serious side effects are less common but can include:
Note: Citrus fruit, especially grapefruit, can increase carbamazepine's adverse effects and should be avoided by those taking this drug.
Uses. Phenytoin (Dilantin) is effective for adults who have the following seizures or conditions:
This drug is not useful for the following seizures:
Side Effects. Side effects are sometimes difficult to control. Some people may develop a toxic response to normal doses, while others, such as those with alcoholism, may require higher doses to achieve benefits. As with any drug, side effects generally rely on dosage and duration. Using phenytoin in combination with newer add-on drugs can allow lower doses and may reduce some of the risks. Side effects may include:
Phenobarbital (Luminal), also called phenobaritone, is a barbiturate anticonvulsant and is often the initial drug prescribed for newborns and young children. It is a relatively inexpensive drug. Primidone (Mysoline) is converted in the body to phenobarbital, and has the same benefits and adverse effects. It is reported that primidone is not as well-tolerated as phenobarbital. Some doctors believe that primidone has no advantage over the other drug.
Uses. Barbiturates are used to also prevent grand mal (tonic-clonic) seizures or partial seizures. They are no longer typically used as a first-line drug.
Side Effects. Phenobarbital has fewer toxic effects on other parts of the body than most anti-epileptic drugs, and drug dependence is unusual, given the low doses used for patients with epilepsy. Nevertheless, withdrawal is common because of side effects, and therefore it is less likely to be used over time than other drugs, including phenytoin, another relatively inexpensive but effective drug.
Patients sometimes describe their state as "zombie-like." The most common and troublesome side effects are:
Some controversy has arisen over studies indicating that children taking phenobarbital score lower on intelligence tests, even for some months after going off the drug.
Uses. Ethosuximide (Zarontin) is used for petit mal (absence) in children and adults when the patient has experienced no other type of seizures. Ethosuximide succeeds in abolishing petit mal seizures in 60% of patients and controls them in up to 90%. Methsuximide (Celontin), a drug similar to ethosuximide, may be suitable as an add-on treatment for intractable epilepsy in children without causing serious or permanent side effects.
Side Effects. Use of this drug can cause stomach problems, dizziness, loss of coordination, and lethargy. In rare cases, it has caused severe and even fatal blood abnormalities. Periodic blood counts are recommended for patients taking this drug.
Uses. Clonazepam (Klonopin) is recommended for myoclonic and atonic seizures that cannot be controlled by other drugs and for Lennox-Gastaut (absence variant). It may be useful in newborns when other drugs are ineffective. Although clonazepam can prevent generalized or partial seizures, patients generally develop tolerance to the drug, and then seizures recur.
Side Effects. People who have had liver disease or acute angle glaucoma should not take clonazepam, and people with lung problems should approach the drug with caution. Clonazepam can be addictive, and abrupt withdrawal has been known to trigger status epilepticus. Side effects include the following: drowsiness, imbalance and staggering, irritability, aggression, hyperactivity in children, weight gain, eye muscle problems, slurred speech, tremors, skin problems, and stomach problems.
Uses. Lamotrigine (Lamictal) is approved as add-on (adjunctive) therapy for partial seizures, and generalized seizures associated with Lennox-Gastaut syndrome, in children aged 2 years and older and in adults. Lamotrigine is also approved as add-on therapy for treatment of primary generalized tonic-clonic (PGTC) seizures, also known as “grand mal” seizures, in children aged 2 years and older and adults. Lamotrigine can be used as a single drug treatment (monotherapy) for adults with partial seizures. Birth control pills lower blood levels of lamotrigine.
Side Effects. Common side effects include dizziness, headache, blurred or double vision, lack of coordination, sleepiness, nausea, vomiting, insomnia, and rash. Although most cases of rash are mild, in rare cases the rash can become very severe. The risk of rash increases if the drug is started at too high a dose or if the patient is also taking valproate. (Serious rash is more common in young children who take the drug than it is in adults.) Rash is most likely to develop within the first 8 weeks of treatment. Be sure to immediately notify your doctor if you develop a rash, even if it is mild.
Gabapentin (Neurontin) is an effective add-on drug for controlling complex partial seizures and secondarily generalized partial seizures and is approved for adults and children with these seizures. It has achieved response rates in patients with resistant partial epilepsy. It is not useful for generalized petit mal seizures.
Side Effects. Its toxicity is low, and side effects include sleepiness, headache, fatigue, and dizziness. Some weight gain has been reported. Gabapentin has no significant interactive effects when taken with other drugs. Children may experience hyperactivity or aggressive behavior. Long-term adverse effects are still unknown.
Pregabalin (Lyrica) is similar to gabapentin.
Uses. Approved as add-on therapy to treat partial-onset seizures in adults with epilepsy. In clinical trials, half of the patients who received pregabalin experienced a 50% reduction in seizure frequency.
Side Effects. These may include dizziness, sleepiness, dry mouth, swelling in hands and feet, blurred vision, weight gain, and trouble concentrating
Uses. Topiramate (Topamax, generic) is similar to phenytoin and carbamazepine and is effective and safe for a wide variety of seizures in adults and children. It is approved as add-on therapy for patients 2 years and older with generalized tonic-clonic seizures, partial-onset seizures, or seizures associated with Lennox-Gastaut syndrome. It is also approved as single drug therapy.
Side Effects. Most side effects are mild to moderate and can be reduced or even prevented by beginning at low doses and increasing dosage gradually. Serious side effects may include glaucoma, decreased sweating, increased body temperature, kidney stones, sleepiness, dizziness, confusion, and trouble concentrating. Patients should immediately tell their doctor if they have blurred vision or eye pain. Topiramate may have fewer interactions with oral contraceptives than other AEDs.
Oxcarbazepine (Trileptal, generic) is similar to phenytoin and carbamazepine but generally has fewer side effects.
Uses. Approved as single therapy or add-on therapy for partial seizures in adults and for children ages 4 years and older.
Side Effects. Serious side effects, while rare, include Stevens-Johnson syndrome and toxic epidermal necrolysis. These skin reactions cause a severe rash that can be life threatening. Rash and fever may also be a sign of multi-organ hypersensitivity, another serious side effect associated with this drug. Oxcarbazepine can also reduce sodium levels (hyponatremia). Your doctor may want to monitor the sodium level in your blood. This drug can also reduce the effectiveness of birth control pills. Women who take oxcarbazepine may need to use a different type of contraceptive.
Zonisamide (Zonegran) is a unique drug that blocks sodium and calcium channels and may have nerve-protecting properties.
Uses. It is approved as add-on therapy for adults with partial seizures, and studies indicate it is often effective against infantile spasms (West syndrome) and myoclonic seizures.
Side Effects. Zonisamide increases the risk for kidney stones, which can be reduced with increased fluid intake and citrate. It has also been associated with reduced sweating and a sudden rise in body temperature, especially in hot weather. Children are especially at risk for this side effect, which can be serious. (The drug has not been approved for children.) Other side effects tend to decrease over time and include dizziness, forgetfulness, headache, weight loss, and nausea.
Levetiracetam (Keppra) is known as a nootropic drug.
Uses. This drug is approved both in oral and intravenous forms as add-on therapy for:
Levetiracetam appears to have fewer drug interactions than other anti-epileptic drugs and may be particularly useful for older patients.
Side Effects. These tend to occur mostly in the first month. They include sleepiness and fatigue, muscle weakness and coordination difficulties, headache, flu symptoms, dizziness, behavioral abnormalities, possible risk of a reduced white blood cell count, and a higher rate of infections. Caution is advised for patients with kidney dysfunction. There have been some reports of adverse effects on mood (irritability, depression, and anxiety), but recent studies have found fewer such effects than with other AEDs. Epilepsy, rather than the drug, is likely to be the cause of these mood changes. About 1% of patients report considerable weight loss.
Tiagabine (Gabitril) has properties similar to phenytoin and carbamazepine, and is also showing promise.
Side Effects. Evidence has reported some significant side effects with its use, including dizziness, fatigue, agitation, and tremor. At least one study suggested that it has more adverse effects than lamotrigine and is not as well tolerated. In February 2005, the FDA issued a warning advising that tiagabine may cause seizures in patients without epilepsy. Tiagabine is only approved for use with other anti-epilepsy medicines to treat partial seizures in adults and children 12 years and older.
Felbamate. Felbamate (Felbatol) is an effective antiseizure drug. However, after reports of deaths from a serious blood condition known as aplastic anemia or from liver failure, felbamate is recommended only under certain circumstances. They include severe epilepsy, such as Lennox-Gastaut syndrome or as monotherapy for partial seizures in adults when other drugs fail.
Vigabatrin. Vigabatrin (Sabril) is a chemical called gamma-vinyl GABA. It was designed to increase the brain levels of gamma aminobutyric acid (GABA), the enzyme that inhibits seizure activity. It has serious side effects, however, and is generally prescribed in the U.S. only in certain cases, such as in low doses for patients with Lennox-Gastaut syndrome. Overseas it is also used for partial seizures and as first-line therapy in children with infantile spasms (West syndrome).
Between 10 - 30% of people on long-term treatment have developed irreversible visual disturbances, including reductions in acuity and color vision. Men are at higher risk for this side effect than are women. Further studies are needed to determine the extent and severity of this complication, particularly in children. There is a slight risk for depression or psychosis when vigabatrin is used as add-on therapy, and particularly if the drug is administered too quickly. These risks are far lower if the drug is used as sole therapy.
Older Drugs. Some older but less effective drugs may still play a role against epilepsy:
Infantile spasms are treated with vigabatrin, adrenocorticotropic hormone (ACTH), or valproate. This condition can be very difficult to treat.
New AEDs. Retigabine is an investigational GABA enhancer that works in a different way from existing AEDs. It is currently in phase III trials for treatment of partial-onset seizures in patients who are receiving other AEDs. Talampanel is another new type of drug, known as an AMAP receptor antagonist, that is currently in early trials. Other drugs under investigation are related to existing AEDs. For example, brivaracetam and seletracetam are similar to levetiraceptam, fluorofelbamate is similar to felbamate, and eslicarbazepine is similar to oxcarbazepine.
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