Adjunctive Epilepsy Medication

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Adjunctive therapy for epilepsy, also referred to as add-on therapy, is the use of more than one anti-epileptic drug (AED) to prevent seizures. Often, the only way to obtain adequate seizure control is by using adjunctive therapy.

There are pros and cons to taking adjunctive therapy, and you can talk to your doctor to discuss the best options for your epilepsy care. This article will review the available adjunctive treatments and how they are used.

Benefits vs. Challenges of Adjunctive Epilepsy Treatment - Illustration by Katie Kerpel

Verywell / Katie Kerpel

Adjunctive Epilepsy Treatments 

Monotherapy is the use of only one medication for the treatment of a condition. Some AEDs are not indicated for monotherapy and are only approved as adjunctive therapy.

Those that are only approved for adjunctive therapy may improve seizure control when they are used in combination with one or more AEDs, but they are not expected to prevent seizures when they are used alone. 

Medications that are approved only for use as adjunctive AEDs include:

  • Briviact (brivaracetam): Approved as adjunctive therapy for preventing partial-onset seizures (begin in one part of the brain), with and without secondary generalization (spreading widely in the brain), for adults and children ages 1 month and older
  • Neurontin (gabapentin): Approved as adjunctive therapy for preventing partial-onset seizures, with and without secondary generalization for adults and children ages 3 and older
  • Zonegran, Zonisade (zonisamide): Approved for adults and children 16 years and older as adjunctive therapy for preventing partial-onset seizures
  • Banzel (rufinamide): Approved for adults and children ages 1 and older as adjunctive therapy for preventing seizures of Lennox-Gastaut syndrome
  • Lyrica (pregabalin): Approved as adjunctive therapy for preventing partial-onset seizures for adults and children ages 1 month and older

Additionally, many AED medications that can effectively control seizures when used alone can also be combined with other anti-epilepsy medications.

For example, AEDs like Lamictal (lamotrigine), Felbatol (felbamate), Fintepla (fenfluramine) and Topamax (topiramate) may be used as monotherapy or as add-on therapy. And some AEDs are approved as monotherapy for some situations and as adjunctive therapy for other situations. 

Maintenance vs. Emergency Treatment

Adjunctive epilepsy treatment is generally considered maintenance therapy for preventing seizures. Other, fast-acting AEDs are used for emergency seizure treatment. You may need one or more AEDs to control seizures in an emergency situation.

When Adjunctive Treatment Is Used 

Often, epilepsy management is started with monotherapy. Monotherapy is usually effective for most people who have a seizure disorder. 

Depending on your seizure control and side effects with monotherapy, your doctor might consider adding another adjunctive AED medication for you in some circumstances.

Reasons to consider adjunctive epilepsy treatment: 

  • Monotherapy is partially effective. You might be experiencing a decrease in the number and/or severity of your seizures with monotherapy. But if you still have some seizures, your doctor may prescribe an additional AED for you to get better seizure control. 
  • Side effects of monotherapy are intolerable. You could be having good seizure control with one AED, but your side effects might necessitate a reduction in the dose. If the reduced dose is inadequate for preventing your seizures, your doctor may prescribe an additional AED for you.
  • You have multiple seizure types. If you have different types of seizures, such as a combination of absence seizures and focal seizures, it's likely that one AED could be effective for treating one type but not for treating another. Your doctor might prescribe more than one AED for you in that situation.
  • There is a risk of drug interactions. If you are starting a new medication that may interact with your current monotherapy AED, your doctor may switch your seizure prevention treatment to avoid interactions. The best switch for you may be a combination of AEDs, rather than just one. 

You and your doctor will discuss the choice between switching from one monotherapy to another monotherapy or using adjunctive therapy based on your specific situation. 

Epilepsy Doctor Discussion Guide

Get our printable guide for your next doctor's appointment to help you ask the right questions.

Briviact is an adjunctive epilepsy medication for ages 16 and older

Pros and Cons of Adjunctive Epilepsy Treatment 

Your doctor will discuss the anticipated effects of adjunctive epilepsy therapy with you if you need to take an add-on AED. 

The potential benefits of add-on therapy for epilepsy include: 

  • Improved seizure control: There are more than 20 AEDs with various mechanisms of action. Sometimes using medications that prevent seizures with different mechanisms can be more effective than using one medication that acts only with one anti-seizure mechanism. 
  • Fewer side effects: You may be able to take lower doses of multiple AEDs when you use add-on therapy. By doing this, you might be able to get enough seizure control without having some of the side effects that could develop from taking a high dose of an AED. 
  • Management of non-epilepsy issues: Some AEDs can treat other problems in addition to epilepsy. For example, Lyrica and Neurontin can be used to treat certain types of pain. You may have multiple health benefits from using certain adjunctive AEDs.

The potential drawbacks of add-on therapy for epilepsy include: 

  • Drug interactions: Some drugs have chemical reactions that change the action or concentration of other drugs when they are used together. Taking multiple AEDs with different chemical compositions can increase your risk of drug interactions. 
  • Different side effects: AEDs can have side effects, and when you take more than one AED, you can be exposed to a wider range of potential side effects.
  • Amplified side effects: Many AEDs have some of the same side effects, especially tiredness, dizziness, and trouble concentrating. Taking multiple AEDs that produce the same side effects can cause these issues to be severe. 
  • Complicated dosing schedule: It can be challenging to take more than one medication, especially if they are taken multiple times per day or on different schedules. Some medications have to be taken with food, while others might need to be taken without food—and this can further complicate things for you. 

Adjusting Doses

If you begin taking adjunctive epilepsy treatment, your doctor might gradually adjust the doses of the AEDs you are taking to reach a therapeutic level with minimal side effects.

Nonmedication Adjunctive Treatment

In general, the most common add-on epilepsy treatment is AED medication. Sometimes, however, other adjunctive approaches are needed for managing epilepsy.

Dietary modifications can sometimes be beneficial for preventing certain types of seizures. When used to treat drug-resistant epilepsy, the ketogenic diet is designed as a high-fat, no-carbohydrate diet.

Other lifestyle strategies, such as using herbs or supplements, have not been proven to prevent seizures, either alone or in combination with AEDs.


Adjunctive therapy for epilepsy is using more than one medication for the control of seizures. Medications may be approved specifically as this add-on therapy, while others may be used as monotherapy or adjunctive therapy.

While monotherapy is effective for most people with epilepsy, adjunctive therapy may be needed to prevent side effects and get better seizure control.

A Word From Verywell

Adjunctive epilepsy medication is often prescribed for optimal seizure control. If you are prescribed more than one AED, be sure to take the medications as prescribed and tell your doctor if you experience any seizures.

Also, it’s important to familiarize yourself with the side effects of each medication that you take so you can let your doctor know if you begin to experience any. In addition to medication, avoiding epilepsy triggers—alcohol, sleep deprivation, not eating, and flashing lights—is also an important aspect of your epilepsy care. 

2 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Brigo F, Lattanzi S, Igwe SC, Behzadifar M, Bragazzi NL. Zonisamide add-on therapy for focal epilepsy. Cochrane Database Syst Rev. 2020 Jul 24;7(7):CD001416. doi:10.1002/14651858.CD001416.pub5

  2. Panebianco M, Prabhakar H, Marson AG. Rufinamide add-on therapy for refractory epilepsy. Cochrane Database Syst Rev. 2018 Apr 25;4(4):CD011772. doi:10.1002/14651858.CD011772.pub2

By Heidi Moawad, MD
Heidi Moawad is a neurologist and expert in the field of brain health and neurological disorders. Dr. Moawad regularly writes and edits health and career content for medical books and publications.