Will missing a dose of anti-epileptic medication cause seizure?

There are different available drugs used for the treatment of epilepsy and seizure.

Some of these drugs are called established anti-epileptic drugs. Established anti-epileptic drugs are medications which are confirmed to be effective in treating epilepsy and seizure.

In this article, we would be answering a popular question about anti-epileptic medications. The question is this: “Will missing a doses of anti-epileptic medication cause seizure”?


Before we continue, let us define what an epilepsy, a seizure and anti-epileptic drugs are.

What is epilepsy?


Epilepsy is a central nervous system or a neuronal disorder that results when their is repeated but unproved seizures in an individual. Take note of the phrase: “repeated but unproved”.

This is to say that having an episode of seizure once in a lifetime doesn’t make one an epileptic patient as external factors can provoke seizures in individuals.

In a similar manner, having seizures more than once in a lifetime, with a known trigger, may not mean that one has an epilepsy.


For instance, an adult who takes an overdose of any of these drugs: antidepressants, diphenhydramine, CNS stimulants, tramadol and isoniazid, can have a Seizure as a result; those who drink excessively can have seizures as a result; those who abuse recreational drugs can have seizures, children with untreated high fever can equally have seizures.

What is seizure?

A seizure is an occurrence resulting from a temporary change in the electrical functioning of the brain leading to a sudden alteration of behaviour and involuntary muscle movements.

Having a seizure or seizures doesn’t translate to being epileptic as it can be triggered by external factors like high fevers, drug abuse, brain infection and injury, etc.

Unless when there is a permanent brain damage as a result of those seizure triggers, upon withdrawal or resolution, the seizures stop for good.

Someone is said to be epileptic when he has two or more unproved seizures.

What is the difference between epilepsy and seizure?

The difference between epilepsy and seizure is that all epileptic patient have seizures but not all persons who have had seizures are epileptic.

Seizures have known triggers but epilepsy occurs without provocations.

What are anti-epileptic drugs?

Anti-epileptic drugs are a group of drugs with proven activities against seizures and therefore, used for the treatment of epilepsy. They help epileptic patients to live without seizures.

Examples of them include Levetiracetam (Keppra), Phenytoin, sodium valproate, carbamazepine, lamotrigine, topiramate among others.

Will missing a doses of anti-epileptic medication cause seizure?

The mechanism of actions of anti-epileptic drugs are complex but they all lead to one thing, “a decrease in membrane excitability or a decrease in neuronal activities in the central nervous system (CNS).

Most of the anti-epileptic medications lead to an increase in the quantity of GABA in the CNS.

GABA is an inhibitory neurotransmitter. Therefore, It has an inhibitory effect in the CNS. This means that high amount of it in the CNS will lower the electrical firing in the brain.

Note, seizure occurs when there is abnormally high neuronal electrical impulse or firing.

So, with a steady high amount of GABA in the CNS, there would be little to no seizures. This scenario only occurs if you always have enough amount of anti-epileptic drug in your body.

Anti-epileptic medications that are taken once daily, take about 24 hours to be completely cleared off the body.

Those that are taken twice daily (12 hourly) take about 12 hourly to be completely cleared off in the blood.

Those that are taken three times daily (8 hourly) get cleared off the serum in about 8 hours.

The implications of these are as follows:

If you’re on anti-epileptic drug that is taken once daily, and you miss a dose of it, you will be exposing your body to chancing of having a seizure.

The chancing increases as the time you missed the dose increases. For this reason, it is recommended that you take your medication immediately you remember it, if you previously missed it, except on situations where the time for the next dose is very close.

Similarly, if you’re on an anti-epileptic drug that is taken two or three times daily and you miss a dose, you are equally exposing your body to chancing of having seizures.

The reason behind this is simple, the anti-epileptic drug that is supposed to protect you against seizure would be zero in your body.

This would allow for a depletion of GABA in the brain. Remember that we earlier stated that GABA is an inhibitory neurotransmitter. So, a low level of it would expose you to high amounts of excitatory neurotransmitters, which can trigger seizures.

It is, therefore, important that you do everything possible to avoid missing your anti-epileptic drugs. You can always set an alarm to remind you.

There are a good number of medications reminder applications out there. Install one in your phone.


Missing a doses of anti-epileptic medication can cause seizure. Strict adherence to your dosing schedule would prevent you from have breakthrough seizures. If you usually don’t remember to take your drugs at the due time, use a pill reminder application.


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