Anticonvulsants are medications mainly prescribed to treat epilepsy. They help control brain activity, reducing the frequency and intensity of seizures or preventing new ones. Because of this, they are also known as antiepileptic drugs or seizure medications.
In addition to epilepsy, some anticonvulsants, such as valproic acid, topiramate, and gabapentin, may also be prescribed to treat neuropathic pain, bipolar disorder, or migraines.
Anticonvulsants should only be used under the guidance of a neurologist and must be taken exactly as prescribed, including at the correct times of day and for the recommended duration of treatment. In some cases, regular blood tests are necessary to monitor drug levels and prevent toxicity.
Indications for use
Anticonvulsants are indicated for:
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Epilepsy, seizure disorders, or absence seizures;
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Status epilepticus;
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Lennox-Gastaut syndrome;
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Infantile spasms caused by West syndrome;
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Neuropathic pain, diabetic neuropathy, and trigeminal neuralgia;
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Migraine;
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Alcohol withdrawal syndrome;
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Central diabetes insipidus.
A neurologist will determine the most appropriate anticonvulsant and dosage to prescribe based on the specific condition being treated.
How they work
Anticonvulsants reduce the excitability of neurons in different ways, including increasing levels of gamma-aminobutyric acid (GABA) in the brain, blocking sodium channels in neuron membranes, and inhibiting calcium channels.
These actions help control abnormal neuronal activity, which can help to prevent or reduce seizures, relieve neuropathic pain, prevent migraines, and stabilize mood in people with bipolar disorder.
Main types
The main types of anticonvulsants include:
1. Carbamazepine
Carbamazepine is an anticonvulsant used to treat epilepsy, simple or complex partial seizures, and generalized tonic-clonic seizures. It can also be prescribed for acute mania in bipolar disorder, alcohol withdrawal syndrome, diabetic neuropathy, trigeminal neuralgia, or central diabetes insipidus.
It is available in pharmacies as immediate- or extended-release tablets (100 mg, 200 mg, or 400 mg), chewable tablets (100 mg), and as an oral suspension (100 mg/5 mL).
How to use: For adults with epilepsy, the starting dose is 100 to 200 mg once or twice daily, which may be increased by a healthcare provider based on treatment response. For children, the oral suspension is preferred, and the dose should be calculated according to age and body weight.
2. Phenytoin
Phenytoin is an anticonvulsant prescribed for epilepsy, seizures, and status epilepticus. It is available as 100 mg capsules, an oral suspension (125 mg/5 mL), and an injectable solution (50 mg/mL) for hospital use.
How to use: For adults, the typical dose is 100 mg three times daily. For children, the dose must be calculated by a pediatrician based on body weight.
3. Phenobarbital
Phenobarbital is a barbiturate with anticonvulsant properties used to treat seizures and epilepsy. Another barbiturate, primidone, can also be prescribed, although it is less commonly used because of a higher risk of allergic reactions.
Phenobarbital is available in 15 mg, 30 mg, 60 mg, and 100 mg tablets, and as an oral solution (20 mg/5 mL), as well as an injectable solution (100 mg/mL) for hospital use.
How to use: The recommended dose for adults is 2 to 3 mg per kilogram of body weight per day. Blood tests should be performed regularly to ensure safe levels, as high doses may cause toxicity.
4. Valproic acid
Valproic acid is an anticonvulsant and mood stabilizer used to treat epilepsy, seizures, absence seizures, and bipolar disorder, and can also be used for migraine prevention. It is available as an oral solution (250 mg/5 mL or 50 mg/mL) and as tablets or capsules (125 mg, 250 mg, or 500 mg).
How to use: For adults and children over 10 years of age, the initial dose is 10 to 15 mg per kilogram of body weight per day. This dose can be gradually increased up to 60 mg/kg/day under medical supervision.
5. Ethosuximide
Ethosuximide is an anticonvulsant prescribed specifically for absence seizures. It is available as a syrup (50 mg/mL or 250 mg/5 mL) and as 250 mg capsules under the brand name Zarontin. It can be used by adults or children over 3 years of age.
How to use: For adults and children over 6 years of age, the initial dose is 10 mL (500 mg) per day, divided into two doses. For children aged 3 to 6 years, the starting dose is 5 mL (250 mg) per day. The doctor may adjust the dose according to treatment response.
6. Lamotrigine
Lamotrigine is a seizure medication used to treat partial and generalized seizures, including tonic-clonic seizures. It can be taken alone (monotherapy) or in combination with other anticonvulsants, such as valproic acid. It is available as tablets of 25 mg, 50 mg, 100 mg, 150 mg, and 200 mg, as well as chewable and orally disintegrating tablets (2 mg, 5 mg, 25 mg).
How to use: For adults and children over 12 years of age, the starting dose is 25 mg once daily for two weeks, followed by 50 mg once daily for two weeks. After that, the doctor may increase the dose by 50 to 100 mg every one to two weeks until the desired response is achieved.
7. Topiramate
Topiramate is an antiepileptic medication indicated for epilepsy, seizures in adults or children with Lennox-Gastaut syndrome, and for migraine prevention in adults. It is available as tablets of 25 mg, 50 mg, 100 mg, and 200 mg, and as sprinkle capsules of 15 mg and 25 mg.
How to use: For adults with epilepsy, the usual starting dose is 25 mg at night for one week. After that, the doctor may increase the dose by 25 to 50 mg per day every one or two weeks, divided into two daily doses.
8. Gabapentin
Gabapentin is an anticonvulsant used to treat epilepsy and partial or generalized seizures in adults or children over 12 years of age. It is also prescribed for neuropathic pain in adults.
It is available as 100 mg, 300 mg, and 400 mg capsules, 600 mg and 800 mg tablets, and as an oral solution (250 mg/5 mL).
How to use: For adults and children over 12 years of age, the starting dose is 300 mg on the first day, 600 mg (divided into two doses) on the second day, and 900 mg (divided into three doses) on the third day. The doctor may increase the dose depending on treatment response.
9. Vigabatrin
Vigabatrin is an anticonvulsant indicated for partial or focal epilepsy that does not respond to other seizure medications or when combination therapy is not well tolerated. It is also prescribed for infantile spasms associated with West syndrome. It is available as 500 mg tablets and 500 mg powder packets for oral solution under the brand name Sabril.
How to use: The initial adult dose is 1000 mg (two 500 mg tablets) taken along with other anticonvulsants. For children, the dose must be calculated according to body weight.
10. Levetiracetam
Levetiracetam is an anticonvulsant used to treat focal or generalized seizures in adults and adolescents over 16 years of age. It can be taken alone (monotherapy) or in combination with other anticonvulsants. It is available as tablets (250 mg, 500 mg, 750 mg, and 1000 mg), as an extended-release form (750 mg or 1000 mg), and as an oral solution (100 mg/mL).
How to use: The starting dose for adults and adolescents is 250 mg twice a day. The doctor may gradually increase the dose up to 1500 mg twice a day, depending on treatment response.
11. Lacosamide
Lacosamide is an anticonvulsant used to treat partial seizures with or without secondary generalization in adults and adolescents over 16 years of age. It can be used alone or in combination with other anticonvulsants. It is available as tablets (50 mg, 100 mg, 150 mg, and 200 mg), as an oral solution (10 mg/mL), and as an intravenous injection (200 mg/20 mL) under the brand name Vimpat.
How to use: The initial dose for adults and adolescents is 100 mg twice daily. A healthcare provider may gradually increase the dose each week up to a maximum of 200 mg twice daily.
Use during pregnancy
The use of anticonvulsants during pregnancy should always be managed by an OBGYN and/or neurologist, as most of these medications can cross the placenta and reach the fetus, potentially affecting development and causing birth defects.
It is usually recommended to take at least 0.4 mg of folic acid daily before and during pregnancy while on anticonvulsants, and vitamin K may also be given during the last month. Pregnant women should also avoid seizure triggers and use relaxation techniques to manage stress.