A seizure is a health condition caused by sudden, abnormal brain activity. Electrical signals in the brain fire rapidly and incorrectly, causing a variety of possible physical symptoms. There are several different types of seizures. Seizure symptoms may include one or a combination of the following: loss of consciousness, muscle tension, uncontrollable muscle movements (aka- “convulsions”), staring spells, sudden loss of muscle control/tone, jerking or twitching in one muscle or group of muscles. Examples of types of seizures include generalized seizures, focal seizures, absence seizures, tonic-clonic seizures, myoclonic seizures, and atonic seizures. There are many environmental and physical causes for seizures, including brain tumours, brain aneurysms, lack of oxygen to the brain, drugs and alcohol, drug and alcohol withdrawal, infection, fever, very high or low blood sugar, sensitivity to flashing lights, strokes, and toxins or poisons.
Most people who have had two or more seizures, especially without any known cause, will be diagnosed with epilepsy, which usually requires long-term treatment with anti-seizure medications. There are also medications used to stop seizures, of any cause, particularly status epilepticus, which is a seizure lasting for more than five minutes, or multiple seizures in a row. Not all people who have had a seizure will require medication treatment, especially if there is a known cause (for example, “febrile seizures,” caused by a high fever will usually resolve on their own without any treatment besides fever-lowering strategies/medication). There are some non-medication treatment options for seizure disorders, including a specialized diet, but this should only be done under a doctor’s supervision. In patients whose seizures are not well-controlled with medications, brain surgery and/or nerve stimulation therapies may be required.
Benzodiazepines are used for short-term seizure treatment, usually to stop seizures in the event of status epilepticus. They work by releasing a chemical in the brain that decreases brain activity. They may also be used for seizure prevention in some seizure disorders, but this is rare due to their addictive properties and a process called “tolerance,” in which the body requires higher and higher doses to produce the same effect. Benzodiazepines can be given orally (only if the patient is conscious), intravenously, rectally, and via nasal spray. Rectal and nasal spray preparations are useful for the treatment of seizures/status epilepticus outside of the hospital setting. Examples of benzodiazepines used for seizures are lorazepam, diazepam, clonazepam, and midazolam.
Valproate is used to treat absence, generalized tonic-clonic, and partial seizures. It works by increasing chemicals that slow brain activity, as well as blocking calcium channels that electrical currents go through in the brain. It is usually taken orally but can also be given IV in status epilepticus to help stop seizures. Several forms of valproate are available, including sodium valproate, valproic acid, divalproex sodium, and valproate semisodium. Monitoring of blood levels may be required for these medications.
Carbamazepine and Oxcarbazepine are used for the treatment of partial, generalized, and tonic-clonic seizures. They act on sodium channels to stop rapid firing in brain cells. They are taken orally. Monitoring of blood levels may be required for these medications.
Phenytoin is used to treat partial and generalized tonic-clonic seizures. It works on sodium channels to stop rapid firing in brain cells but also has other possible mechanisms of action, such as decreasing transmission between neuron cells. It is usually taken orally but can also be given in an IV to stop seizures in status epilepticus. It also requires occasional monitoring of blood levels and has several possible drug interactions.
Topiramate is used to treat partial, absence, and generalized tonic-clonic seizures. It works on sodium channels to stop rapid firing in brain cells and increases two brain chemicals that slow brain activity.
Levetiracetam can be used to treat most types of seizures. Its exact mechanism of action isn’t clear, but it is thought to work on several proteins and ion channels involved in electrical signal transmission in the brain. This medication has much fewer drug interactions than most other commonly used anti-seizure medications.
Ethosuximide is used to treat absence seizures. It works by decreasing nerve signal transmission, mostly by blocking calcium channels in the brain.
Lamotrigine is used to treat partial and generalized seizures. It works on sodium channels to decrease brain signal transmission and inhibits a chemical in the brain that causes increased brain activity.
Perampanel is used to treat partial seizures and generalized tonic-clonic seizures. It works by blocking a brain chemical that causes increased brain activity. This medication may cause serious behavioural and psychiatric issues.
Phenobarbital is used for partial and generalized seizures and can also be used IV to treat status epilepticus. Because it is so sedating, it is difficult to use daily as an anti-seizure medication. This is a very old medication that works by increasing levels of a chemical that slows brain activity. It has many drug interactions. Another medication in the same class is primidone.
Gabapentin and Pregabalin are rarely used for seizures but are sometimes used for the treatment of focal/partial seizures. They are similar to a chemical in the body that slows brain activity and work on calcium channels to decrease electrical nerve transmission. These medications are more often used for the treatment of nerve pain.
Vigabatrin is used for focal seizures that do not respond well to other treatments and for infantile spasms. It works by increasing levels of a chemical that decreases brain activity.
Because many anti-seizure medications are available, there is a wide variety of possible side effects. The most common side effects you might experience while taking medications for seizure disorders are:
-Drowsiness/fatigue -Weakness -Weight loss
-Dizziness -Vision changes -Coordination and balance issues
-Nausea -Behaviour changes -Loss of appetite
-Insomnia -Headache -Memory problems/confusion
Stevens-Johnson Syndrome is a rare, but serious drug reaction that begins with flu-like symptoms and progresses into a severe, widespread skin rash that includes blisters involving the mucous membranes (inside the mouth, nose, eyes, and gastrointestinal and respiratory tracts). The skin will usually slough off. This is a medical emergency that can cause dehydration and extreme pain and requires treatment in a hospital. While rare, this condition is known to be more likely to occur in patients taking certain anti-seizure medications, including carbamazepine, lamotrigine, and phenytoin. If you are taking one of these medications (especially if newly prescribed) and experience flu-like symptoms (fever, headache, sore throat) followed by a skin rash, you should seek medical attention right away.
It is important that you take your seizure medications exactly as prescribed. Missing a dose or stopping seizure medication suddenly may increase your risk of having a seizure. Sometimes, it may be possible to stop seizure medications, but it should only be done under the close supervision of a healthcare provider. You may, however, need to take seizure medications for the rest of your life. Seizures can be life-threatening medical emergencies, so it is important that they are well-controlled. You must tell your doctor and/or pharmacist all medications you are taking, because of possible serious drug interactions with anti-seizure medications. It is also important to follow up with your doctor regularly and have routine bloodwork done to ensure that drug levels are appropriate and the medications are not causing any organ damage or blood abnormalities. It may take more than one medication to control seizures adequately, and it may require trying multiple medications before finding one (or more) that works best for you.