Merck Manual

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Drugs Used to Treat Seizures

Drugs Used to Treat Seizures

Drug

Use

Some Side Effects

Acetazolamide

Absence seizures when other antiseizure drugs are ineffective

Kidney stones, dehydration, and chemical imbalances in the blood

Cannabidiol

Dravet syndrome

Tonic or atonic seizures in Lennox-Gastaut syndrome*

Drowsiness, liver damage, loss of appetite, fatigue, insomnia, and diarrhea

Carbamazepine

Focal-onset seizures

Secondarily generalized-onset seizures (including focal-to-bilateral tonic-clonic seizures)

A low white blood cell count (granulocytopenia), production of too few blood cells (aplastic anemia, which can be fatal), a low platelet count (thrombocytopenia), a severe rash, digestive upset, liver damage, slurred speech (dysarthria), lethargy, dizziness, and double vision

Clobazam

Absence seizures

Dravet syndrome

Focal-onset or focal-to-bilateral tonic-clonic seizures† when other antiseizure drugs are ineffective

Sometimes tonic or atonic seizures in Lennox-Gastaut syndrome*

Drowsiness, constipation, loss of coordination, thoughts of suicide, dependency on the drug, irritability, and difficulty swallowing

Clonazepam

Atonic seizures

Atypical absence seizures in Lennox-Gastaut syndrome*

Epileptic (infantile) spasms

Myoclonic seizures

Drowsiness, abnormal behavior, loss of coordination, and lost effectiveness of the drug after 1 to 6 months

Divalproex‡

Absence seizures

Epileptic spasms

Focal-onset seizures

Generalized-onset tonic-clonic seizures

Juvenile myoclonic epilepsy

Myoclonic seizures

Tonic or atonic seizures in Lennox-Gastaut syndrome*

Nausea, vomiting, abdominal pain, diarrhea, temporary drowsiness, shaking (tremor), reversible hair loss, weight gain, and liver damage

A somewhat higher risk of spinal cord, spine, or brain birth defects (neural tube defects) than with other antiseizure drugs

Eslicarbazepine

Focal-onset seizures

Dizziness or shakiness, double or blurred vision, drowsiness, headache, nausea, vomiting, a low sodium level in the blood, thoughts of suicide, and skin reactions, such as rash (sometimes serious)

Ethosuximide

Absence seizures

Nausea, lethargy, dizziness, headache, rash, and a low blood cell count (of all types of blood cells)

Felbamate

Used only when other antiseizure drugs are ineffective

Atypical absence seizures in Lennox-Gastaut syndrome*

Focal-onset seizures

Headache, fatigue, liver failure, and, rarely, aplastic anemia (which can be fatal)

Fosphenytoin§

Focal impaired-awareness seizures

Status epilepticus

Focal-to-bilateral tonic-clonic seizures

Prevention of seizures after a head injury

Loss of coordination, drowsiness, dizziness, headache, itching, and tingling sensations

Gabapentin

Focal-onset seizures

Focal-to-bilateral tonic-clonic seizures†

Drowsiness, dizziness, weight gain, and headache

In children, sleepiness, aggressive behavior, mood swings, and hyperactivity

Lacosamide

Focal-onset seizures

Dizziness, double vision, and thoughts of suicide

Lamotrigine

Focal-onset seizures

Generalized-onset seizures in Lennox-Gastaut syndrome*

Generalized-onset tonic-clonic seizures

Nausea, vomiting, constipation, headache, drowsiness, dizziness, insomnia, fatigue, loss of coordination, double vision, tremor, abnormal menstrual periods, and rash

Levetiracetam

Focal-onset seizures

Juvenile myoclonic epilepsy

Myoclonic seizures

Generalized-onset seizures

Dizziness, weakness, fatigue, loss of coordination, and changes in mood and behavior

Oxcarbazepine

Focal-onset seizures

Headache, abdominal pain, double vision, drowsiness, dizziness, fatigue, nausea, and low sodium levels in the blood

Perampanel

Focal-onset seizures

Generalized-onset tonic-clonic seizures

Aggressiveness, changes in mood and behavior, thoughts of suicide, dizziness, fatigue, irritability, falls, sleepiness, nausea, vomiting, headache, weight gain, abdominal pain, and problems walking

Phenobarbital

Focal-onset seizures

Generalized-onset tonic-clonic seizures

Neonatal seizures

Status epilepticus

Drowsiness, abnormal eye movements (nystagmus), loss of coordination, anemia, and rash

In children, hyperactivity and learning difficulties

Phenytoin§

Focal impaired-awareness seizures

Focal-to-bilateral tonic-clonic seizures

Status epilepticus (phenytoin is given intravenously)

Prevention of seizures after a head injury

Swollen gums, a low red blood cell count (anemia), loss of bone density, excessive hairiness (hirsutism), rash, and swollen glands

When high doses of phenytoin are given, loss of coordination, slurred speech, abnormal eye movements, lethargy, confusion, drowsiness, nausea, and vomiting

Pregabalin

Focal-onset seizures

Dizziness, drowsiness, loss of coordination, blurred vision, double vision, tremor, and weight gain

Tiagabine

Focal-onset seizures

Drowsiness, dizziness, confusion, slow thinking, abdominal pain, fatigue, nausea, and tremor

Topiramate

Atypical absence seizures

Dravet syndrome

Focal-onset seizures

Generalized-onset tonic-clonic seizures

Confusion, reduced concentration, difficulty finding words, fatigue, loss of appetite and weight, numbness or tingling, reduced sweating, and kidney stones

Valproate‡

Absence seizures

Dravet syndrome

Febrile seizures

Focal-onset seizures

Generalized-onset tonic-clonic seizures

Epileptic spasms

Juvenile myoclonic epilepsy

Myoclonic seizures

Neonatal seizures

Tonic or atonic seizures in Lennox-Gastaut syndrome*

Nausea, vomiting, abdominal pain, diarrhea, weight gain, reversible hair loss, temporary drowsiness, tremor, and, rarely, liver damage

A somewhat higher risk of spinal cord, spine, or brain birth defects (neural tube defects) than with other antiseizure drugs

Vigabatrin

Epileptic spasms

Focal-onset seizures

Drowsiness, dizziness, headache, fatigue, and permanent changes in vision

Zonisamide

Focal-onset seizures

Sometimes tonic or atonic seizures in Lennox-Gastaut syndrome*

Drowsiness, fatigue, dizziness, confusion, difficulty finding words, loss of coordination, kidney stones, loss of appetite and weight, and nausea

* Atypical absence seizures, atonic seizures, and tonic seizures usually occur as part of a severe form of epilepsy called Lennox-Gastaut syndrome, which begins before children are 4 years old.

† Focal-to-bilateral seizures are seizures that start on one side of the brain and spread to both sides.

‡ Divalproex and valproate are similar

§ Fosphenytoin and phenytoin are similar.