Overview of 7 most common seizure medications

Over the past century, scientists have discovered an ever-growing range of seizure medications. Today, there are around 30 epilepsy drugs approved in the US. They all work slightly differently, and help treat different sorts of seizures. 

Since there are so many anti-epilepsy drugs (AEDs) out there, it can get confusing talking to your doctor and pharmacist about them. We’ve compiled this seizure medications list to help you understand the seven most widely used AEDs in the US. 

Of course, our seizure medications list doesn’t cover every medication or all information about how they work. The Epilepsy Foundation maintains a reliable list of all AEDs currently approved in the US. 

Suggested: Why might an AED not work for you?

7 most common seizure medications

When you are first diagnosed with epilepsy, your doctor will usually try to treat the condition with medication. The seven AEDs in this list are the most common ‘first line’ medications used for different kinds of epilepsy. 

For some people, these ‘first line’ drugs work right away. But for others, the AED either doesn’t work, or the seizure medication side effects are very unpleasant. If so, their doctor will normally try an alternative medicine. For about one-third of people with epilepsy, medication doesn’t work. Fortunately, there are other treatment options available. 

1. Valproic Acid

Brand names: Depakote, Depakene

Form: Can be taken as tablets, liquids, or granules (sprinkled on food)

Treats: Generalized, focal, absence - effective with most kinds of epilepsy

Since being introduced in 1978, Valproic Acid has become the most widely prescribed AED in the world. You will usually take it once or twice per day, in varying doses, depending on your age and weight. 

Valproic Acid works by making it hard for your brain cells to work as fast, which means they can’t ‘fire’ off as much during a seizure. 

Valproic Acid common side effects: 

• Upset stomach
• Dizziness
• Tiredness
• Weight gain
• Shaking/tremor

How effective is Valproic Acid? It varies depending on the seizure type, but in one study, 88% of people saw a reduction in seizures, and 50% became seizure free after six months. 

2. Lamotrigine

Brand names: Lamictal

Form: Comes as tablets you can swallow or chew

Treats: Generalized (tonic clonic) seizures; atonic seizures

Lamotrigine is a widely used seizure medication among people with generalized epilepsy. You’ll take the tablets once or twice per day. It works by slowing down the bursts of electrical signals in the brain that happen during a seizure. Lamotrigine appears to be one of the safer AEDs to take during pregnancy - unlike many other epilepsy medications. 

Lamictal side effects: 

• Headaches
• Feeling tired
• Dizziness
• Feeling irritable
• Skin rash
• Feeling sick

How effective is Lamotrigine? One recent study found that about 60% of people were able to control their seizures with Lamotrigine after six months - although it’s more effective among women than men. 

3. Topiramate

Brand names: Topamax

Form: Comes as tablets to swallow

Treats: Generalized (tonic clonic) seizures; atonic seizures; Lennox-Gastaut syndrome

Topiramate is mainly used to treat generalized epilepsy. You’ll usually take the tablets twice per day. Like with other AEDs, it works by slowing down how fast your brain cells work, which helps stop seizures from developing. It should not be used if you are pregnant. 

Topiramate common side effects: 

• Feeling sick 
• Dizziness
• Depression
• Weight loss
• Losing your appetite

How effective is Topiramate? One study reported that Topiramate can help over 80% of people achieve full seizure control in as little as two months. 

Issues with AEDs: Seizure medicine side effects

4. Carbamazepine

Brand names: Tegretol, Curatil

Form: Comes as tablets, liquids and suppositories

Treats: Focal seizures

Carbamazepine is a sodium channel blocker which was first approved to treat epilepsy in 1968. Sodium ion channels work a bit like gates in the brain, so by blocking them carbamazepine slows down how quickly signals get sent. It should not be used if you are pregnant. 

Side effects from Tegretol: 

• Drowsiness
• Dizziness
• Headaches
• Feeling sick

How effective is Carbamazepine? One study found that about 70% of people achieved seizure freedom while using Carbamazepine after six months. 

5. Phenytoin

Brand names: Dilantin

Form: Comes as tablets for swallowing or chewing and as a liquid

Treats: Focal seizures

Phenytoin was first approved by the FDA in 1939. It is believed to work by blocking sodium ion channels in the brain, and therefore stops high frequency firing of electric signals in the brain.  

Phenytoin common side effects: 

• Nausea
• Stomach discomfort
• Loss of appetite
• Poor coordination (trouble with walking, balance, etc.)

How effective is Phenytoin? Phenytoin is generally regarded as very effective - various studies show it has similar levels of efficacy as other common AEDs. 

6. Oxcarbazepine

Brand names: Trileptal, Oxtellar XR

Form: Comes as tablets form, or as a liquid

Treats: Focal seizures

Oxcarbazepine is used to treat focal seizures and comes in quick and slow release forms. It’s not fully known how this AED works, but it’s believed that it blocks sodium channels in the brain. 

Oxcarbazepine common side effects: 

• Dizziness
• Double vision
• Headache
• Trembling
• Poor coordination

How effective is Oxcarbazepine? Studies suggest Oxcarbazepine is as effective as other common AEDs like Phenytoin and Valproic Acid. 

7. Ethosuximide

Brand names: Zarontin

Form: Comes as tablets for or as a liquid

Treats: Absence seizures

Ethosuximide is a seizure medicine which is mainly used for the treatment of absence seizures, especially for children. We still don’t know quite how it works, but it seems to stop brain cells from firing so fast. 

Ethosuximide common side effects: 

• Upset stomach
• Loss of appetite
• Diarrhea

How effective is Ethosuximide? Multiple studies suggest that Ethosuximide is one the most effective seizure medications for kids with absence seizures. 

What if seizure medications don’t work?

Over the past hundred years, scientists have discovered many powerful and effective AEDs which help many people lead seizure-free lives. These advances are great news for the epilepsy community as a whole. But many people who take AEDs find that they just don’t work for them - about one third of people have ‘refractory epilepsy’, which means they’ve tried two or more AEDs without being able to control their seizures.  

The good news is that there are several alternative ways of treating epilepsy if AEDs don’t seem to work. These include special diets and medical devices. Learn more about alternative epilepsy treatment pathways in our blog.