Lamotrigine with Oxcarbazepine Interaction Details
Brand Names Associated with Lamotrigine
- Lamictal®
- Lamictal® CD
- Lamictal® ODT
- Lamictal® XR
- Lamotrigine
Brand Names Associated with Oxcarbazepine
- Oxcarbazepine
- Oxtellar XR®
- Trileptal®
Medical Content Editor Dr. Brian Staiger, PharmD
Last updated
Nov 08, 2023
Interaction Effect
Reduced lamotrigine concentrations and possible loss of seizure control
Interaction Summary
Oxcarbazepine is structurally similar to carbamazepine but does not form an epoxide metabolite, which is considered responsible for the neurotoxic effects of carbamazepine. When lamotrigine and oxcarbazepine were administered concurrently to 14 patients with epilepsy, plasma concentrations of lamotrigine were decreased 28.7% compared to lamotrigine monotherapy. In two patients who had received lamotrigine and oxcarbazepine concurrently, oral ulcers occurred several weeks after oxcarbazepine discontinuation or dose reduction. Induction of lamotrigine metabolism by oxcarbazepine was postulated to be the mechanism, such oxcarbazepine discontinuation or a dose reduction may have resulted in a slow increase in lamotrigine levels, thereby increasing its toxicity . Concomitant use of lamotrigine and oxcarbazepine may require monitoring the patient closely for seizure control and increasing the lamotrigine dose as necessary. Conversely, in patients receiving these agents concurrently, if oxcarbazepine is discontinued or its dose is reduced, lamotrigine doses may need to be reduced. Additionally, the patient may need to be monitored over several weeks for signs/symptoms of lamotrigine toxicity.
Severity
Moderate
Onset
Delayed
Evidence
Probable
How To Manage Interaction
Monitor seizure control and anticipate a possible need to increase lamotrigine doses if oxcarbazepine is added to therapy. Conversely, if oxcarbazepine is withdrawn from therapy or if dosage is reduced, lamotrigine doses may need to be reduced and the patient may need to be monitored over several weeks for symptoms of lamotrigine toxicity.
Mechanism Of Interaction
Hepatic induction by oxcarbazepine of lamotrigine metabolism
Literature Reports
A) Two patients, receiving lamotrigine and oxcarbazepine concurrently, experienced oral ulcers several weeks after oxcarbazepine discontinuation or dose reduction. In the first case, a 35-year-old woman being treated for bipolar II disorder (BD II), hypothyroidism, gastritis, migraines, and asthma was admitted after experiencing one week of worsening depression and two days of suicidal thoughts and treated with oxcarbazepine 600 mg/day, topiramate, fluoxetine, aripiprazole, quetiapine, lithium, naproxen, pantoprazole, amoxicillin, and levothyroxine. On day 2, lamotrigine 50 mg/day was initiated and titrated up to 200 mg/day by day 6. Oxcarbazepine dose was decreased and stopped by day 5, and she was discharged on day 8 with lamotrigine 200 mg, topiramate, aripiprazole, escitalopram, naproxen, pantoprazole, levothyroxine, and hydroxyzine. On day 42 (41 days after starting lamotrigine and 39 days after stopping oxcarbazepine), she developed painful tongue ulcers. Subsequently, lamotrigine was stopped and the ulcers resolved in 4 days. In the second case, a 36-year-old man with BD II, hypertension, and GERD was admitted following a suicide attempt and prescribed oxcarbazepine 600 mg/day, phenytoin, lithium, venlafaxine, mirtazapine, metoprolol, and famotidine. Lamotrigine 50 mg/day was initiated on day 11 and titrated up to 100 mg/day by day 14. He was discharged on day 14 with lamotrigine 100 mg and oxcarbazepine 1200 mg (along with other medications); however, he reduced the oxcarbazepine dose to 600 mg/day after discharge. On day 44 (22 days after oxcarbazepine dose decrease), he developed several painful mouth sores on his lips, gums, and tongue. Both lamotrigine and oxcarbazepine were discontinued and the ulcers resolved completely .
B) Lamotrigine serum concentrations from 222 patients receiving lamotrigine monotherapy (n = 64) or combination therapy with another antiepileptic agent were evaluated. Fourteen patients were being treated with lamotrigine and oxcarbazepine. In the lamotrigine monotherapy group, the lamotrigine concentration was 7.14 mcg/mL (27.88 mcmol/L) while the mean dose was 7.27 mg/dose/kg. The lamotrigine level-to-dose ratio (LDR) in this group calculated out to 1.07 mcg/mL/mg/kg. In the subjects receiving oxcarbazepine in addition to lamotrigine, the plasma concentration was 4.73 mcg/mL (18.47 mcmol/L) while the mean dose was 6.53 mg/dose/kg. The lamotrigine LDR in this group was 0.71 mcg/mL/mg/kg, demonstrating the inducing properties of oxcarbazepine on lamotrigine metabolism .
Lamotrigine Overview
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Lamotrigine extended-release (long-acting) tablets are used with other medications to treat certain types of seizures in patients who have epilepsy. All types of lamotrigine tablets (tablets, orally disintegrating tablets, and chewable tablets) other than the extended-release tablets are used alone or with other medications to treat seizures in people who have epilepsy or Lennox-Gastaut syndrome (a disorder that causes seizures and often causes developmental delays). All types of lamotrigine tablets other than the extended-release tablets are also used to increase the time between episodes of depression, mania (frenzied or abnormally excited mood), and other abnormal moods in patients with bipolar I disorder (manic-depressive disorder; a disease that causes episodes of depression, episodes of mania, and other abnormal moods). Lamotrigine has not been shown to be effective when people experience the actual episodes of depression or mania, so other medications must be used to help people recover from these episodes. Lamotrigine is in a class of medications called anticonvulsants. It works by decreasing abnormal electrical activity in the brain.
Oxcarbazepine Overview
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Oxcarbazepine (Trileptal) is used alone or in combination with other medications to control certain types of seizures in adults and children. Oxcarbazepine extended-release tablets (Oxtellar XR) are used in combination with other medications to control certain types of seizures in adults and children 6 years of age and older. Oxcarbazepine is in a class of medications called anticonvulsants. It works by decreasing 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.
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Information for our drug interactions is compiled from several drug compendia, including:
The prescribing information for each drug, as published on DailyMED, is also used.
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