What are anticonvulsants?
Anticonvulsants are a group of medications that are mainly utilized in patients with epilepsy but may also be useful in treating neuropathic pain, bipolar affective disorder, and preventing migraine. The article summarises the workings and problems related to common anticonvulsant drugs.
Anticonvulsants to control seizure: How they help?
Treatment with anticonvulsant drugs generally is started following two episodes of seizures, when another seizure attack is probable, and when the potential benefits outweigh the possible risks associated with the medicine. Some evidence shows that initiating treatment with anticonvulsants after a single seizure may not cause improvement in the long term and may not reduce the risk of injury or death.
Anticonvulsants are selected based on epileptic seizure, the risk of side effects, and the presence of any other medical condition. For generalized epilepsy syndrome, sodium valproate is the first-line treatment. However, in women with reproductive potential, low doses of carbamazepine and lamotrigine are primarily used because of the toxic effects related to sodium valproate. Carbamazepine and lamotrigine are the top picks for patients with partial seizures.
An antiepileptic treatment aims to achieve control over seizures. They are prescribed to suppress the rapid attack of neurons that are responsible for initiating a seizure attack. Anticonvulsant medications are effective at reducing the frequency as well as severity of seizures in people who have epilepsy.
Note that Anticonvulsants are only effective at treating symptoms of seizures and not the underlying epileptic condition. However, for some individuals, successful treatment goals may not be achievable without intolerable adverse reactions.
About seizures and epilepsy
Seizures are defined as neurological dysfunction due to the abnormal synchronous activity of neurons in the brain.
Epilepsy is a health condition characterized by recurrent seizures. It includes disorders due to excessive excitability of neurons within the central nervous system.
Classification of Anticonvulsant drugs
Uses of anticonvulsants from the classical category include:
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- Phenytoin: As categorized under the classical drugs of the anticonvulsant group, Phenytoin is the most widely used and the oldest anticonvulsant. Generally, it is prescribed to gain control over certain types of seizures as well as to treat and prevent seizures. Its action mechanism includes reducing abnormal electrical activity in the brain. The working mechanism is not completely known but is believed to be related to the effect on sodium ion channels.
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- Primidone: It is effective against psychomotor and focal epileptic seizures. This anticonvulsant is used as monotherapy or in combination with other medication to control seizures in patients with epilepsy. It functions in the brain tissue to stop seizures.
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- Barbiturates: These are mainly sedatives with anticonvulsant activities, which means they cause you to feel relaxed or sleepy. Very few of them are utilized as antiepileptic drugs.
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- Phenobarbital: A long-lasting barbiturate and anticonvulsant used in controlling all types of seizures in patients with epilepsy. It induces a calming effect on the overactive nerves in your body.
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- Ethosuximide: It stops seizures by reducing the abnormal electrical activity in the brain.
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- Carbamazepine: It is more of a stabilizing drug of the anticonvulsant category used to treat epilepsy and bipolar disorder (manic depression). Bipolar disorder is a mental health condition that contributes to extreme mood swings.
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- Trimethadione: It is a commonly prescribed anticonvulsant drug for patients with epileptic conditions that are specifically resistant to other treatments.
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- Sodium valproate (Dicorate ER 750 mg, Dicorate ER 500mg): The exact mode of action is still not understood, but it is effective in treating bipolar disorder, epilepsy, and major depression.
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- Benzodiazepines: These can be utilized in epilepsy treatment to decrease seizures. Two drugs that are frequently used include lorazepam and diazepam. These are preferred choices because of the rapid action after receiving an intravenous injection.
Drugs such as Topiramate (Topamac 25 mg), Oxcarbamazepine (Oxcarb 600mg), and Zonisamide (Zonisep 100 mg) are also anticonvulsants used to treat seizures.
The newer ones include:
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- Gabapentin: It was originally developed for patients with epilepsy and is currently utilized as a pain relief therapy for relieving neuropathic pain.
- Lamotrigine: It is effective in treating epilepsy and bipolar disorder. It slows down the electrical signals in the brain to control seizures. When it comes to treating bipolar disorder, the exact mode of action of the drug is not known how it prevents low mood.
- Tiagabine: It can’t cure epilepsy but works effectively to control seizures as long as you continue taking the medicine.
- Vigabatrin: It can be used as a monotherapy or a combination therapy to treat complex partial seizures in adults and children two years of age and older. It is especially prescribed to patients who have already been treated with other medications that have failed to work well in controlling seizures.
Dose adjustments
Dose adjustments should be done in patients with liver problems. Most of these anticonvulsant drugs tend to be metabolized by the liver. In case of reduced liver function, lower doses of anticonvulsants are recommended to avoid increased drug levels. Levetiracetam, gabapentin, pregabalin, and vigabatrin are excreted without metabolism by the liver and do not need any dose adjustment in individuals with impaired liver function. Consult your doctor to get the best anticonvulsant drugs that suit you. Dose adjustment is also required in individuals with impaired kidney function. In elderly patients, lower doses of anticonvulsants are required.
Side effects of anticonvulsant drugs
Anticonvulsant treatment has some adverse effects, including sedation, dizziness, tiredness, tremor, ataxia, confusion, slurred speech, confusion, decreased coordination, diarrhea, dry mouth, and gastrointestinal disturbance.
These anticonvulsant side effects are generally mild to moderate, disappearing within a few weeks of starting the treatment. These side effects are usually minimized using the lowest doses to avoid a rapid rise in serum concentration. The dose may increase slowly at one or two-week intervals. Using it as a monotherapy can also minimize the occurrence of related side effects of anticonvulsants.
