Topiramate with Carbamazepine Interaction Details

Brand Names Associated with Topiramate

Brand Names Associated with Carbamazepine

Medical Content Editor Dr. Brian Staiger, PharmD
Last updated Nov 25, 2023

Interaction Effect

Reduced topiramate exposure

Interaction Summary

Concomitant use of carBAMazepine and topiramate has resulted in a clinically significant decrease in plasma concentrations of topiramate when compared to topiramate given alone. The mean topiramate AUC, Cmax, Cmin, and Cavg were all approximately 40% lower during carBAMazepine treatment as compared to topiramate monotherapy . A dosage adjustment may be needed .

Severity

Major

Onset

Unspecified

Evidence

Established

How To Manage Interaction

Concomitant use of carBAMazepine and topiramate has resulted in a clinically significant decrease in plasma concentrations of topiramate when compared to topiramate given alone. A dosage adjustment may be needed.

Mechanism Of Interaction

Unknown

Literature Reports

A) In a study in patients with epilepsy receiving concomitant carBAMazepine and immediate-release topiramate, the topiramate concentration decreased 40% compared with patients receiving topiramate alone .

B) Twelve patients with partial epilepsy receiving chronic stable doses of carBAMazepine were enrolled in a study to determine the steady-state pharmacokinetic profile of topiramate and the effects of comedication with carBAMazepine. All subjects were receiving carBAMazepine in doses of 300 mg to 800 mg every 8 hours. Topiramate was added and doses were increased at approximately 2 week intervals until the highest tolerated dose was reached. CarBAMazepine was then tapered off over the next 4 weeks, and topiramate was maintained as monotherapy for 2 more weeks. Results showed that the mean topiramate area under the concentration-time curve (AUC), Cmax, Cmin, and Cavg values were all approximately 40% lower during carBAMazepine treatment as compared to topiramate monotherapy. These results suggest that the metabolic clearance of topiramate increases when carBAMazepine is coadministered. There were no significant changes in the carBAMazepine pharmacokinetic profile during topiramate administration .

Topiramate Overview

• Topiramate is used alone or with other medications to treat certain types of seizures including primary generalized tonic-clonic seizures (formerly known as a grand mal seizure; seizure that involves the entire body) and partial onset seizures (seizures that involve only one part of the brain). Topiramate is also used with other medications to control seizures in people who have Lennox-Gastaut syndrome (a disorder that causes seizures and developmental delays). Topiramate is also used to prevent migraine headaches but not to relieve the pain of migraine headaches when they occur. Topiramate is in a class of medications called anticonvulsants. It works by decreasing abnormal excitement in the brain.

Carbamazepine Overview

• Carbamazepine is used alone or in combination with other medications to control certain types of seizures in people with epilepsy. It is also used to treat trigeminal neuralgia (a condition that causes facial nerve pain). Carbamazepine extended-release capsules (Equetro brand only) are also used to treat episodes of mania (frenzied, abnormally excited or irritated mood) or mixed episodes (symptoms of mania and depression that happen at the same time) in patients with bipolar I disorder (manic-depressive disorder; a disease that causes episodes of depression, episodes of mania, and other abnormal moods). Carbamazepine is in a class of medications called anticonvulsants. It works by reducing abnormal electrical activity in the brain.

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Definitions

Severity Categories

Contraindicated

These drugs, generally, should not be used together simultaneously due to the high risk of severe adverse effects. Combining these medications can lead to dangerous health outcomes and should be strictly avoided unless otherwise instructed by your provider.

Major

This interaction could result in very serious and potentially life-threatening consequences. If you are taking this drug combination, it is very important to be under close medical supervision to minimize severe side effects and ensure your safety. It may be necessary to change a medication or dosage to prevent harm.

Moderate

This interaction has the potential to worsen your medical condition or alter the effectiveness of your treatment. It's important that you are monitored closely and you potentially may need to make adjustments in your treatment plan or drug dosage to maintain optimal health.

Minor

While this interaction is unlikely to cause significant problems, it could intensify side effects or reduce the effectiveness of one or both medications. Monitoring for changes in symptoms and your condition is recommended, and adjustments may be made if needed to manage any increased or more pronounced side effects.

Onset

Rapid: Onset of drug interaction typically occurs within 24 hours of co-administration.

Delayed: Onset of drug interaction typically occurs more than 24 hours after co-administration.

Evidence

Level of documentation of the interaction.

Established: The interaction is documented and substantiated in peer-reviewed medical literature.

Theoretical: This interaction is not fully supported by current medical evidence or well-documented sources, but it is based on known drug mechanisms, drug effects, and other relevant information.

How To Manage The Interaction

Provides a detailed discussion on how patients and clinicians can approach the identified drug interaction as well as offers guidance on what to expect and strategies to potentially mitigate the effects of the interaction. This may include recommendations on adjusting medication dosages, altering the timing of drug administration, or closely monitoring for specific symptoms.

It's important to note that all medical situations are unique, and management approaches should be tailored to individual circumstances. Patients should always consult their healthcare provider for personalized advice and guidance on managing drug interactions effectively.

Mechanism Of Interaction

The theorized or clinically determined reason (i.e., mechanism) why the drug-drug interaction occurs.

Disclaimer: The information provided on this page is for informational purposes only and should not be considered medical advice. Always consult with a qualified healthcare professional regarding your specific circumstances and medical conditions.

Where Does Our Information Come From?

Information for our drug interactions is compiled from several drug compendia, including:

• Gold Standard Drug Database
• Micromedex
• Lexicomp
• DrugBank

The prescribing information for each drug, as published on DailyMED, is also used. 

Individual drug-drug interaction detail pages contain references specific to that interaction. You can click on the reference number within brackets '[]' to see what reference was utilized.

The information posted is fact-checked by HelloPharmacist clinicians and reviewed quarterly.