Carbamazepine with Vecuronium Interaction Details
Brand Names Associated with Carbamazepine
- Carbamazepine
- Carbatrol®
- Epitol®
- Equetro®
- Tegretol®
- Tegretol®-XR
- Teril®
Medical Content Editor Dr. Brian Staiger, PharmD
Last updated
Nov 25, 2023
Interaction Effect
Decreased vecuronium duration of action
Interaction Summary
Patients on carbamazepine maintenance therapy required significantly higher doses of vecuronium to achieve similar neuromuscular blocking effects as controls. This may be a result of a pharmacokinetic interaction between carbamazepine and vecuronium, although a pharmacodynamic interaction still cannot be ruled out .
Severity
Moderate
Onset
Rapid
Evidence
Established
How To Manage Interaction
Monitor patients for an appropriate clinical response to the neuromuscular blocker. Closer dosing intervals or higher doses of vecuronium may be needed in patients receiving carbamazepine.
Mechanism Of Interaction
Increased clearance of vecuronium
Literature Reports
A) Twenty-four surgical patients were evaluated, of which eight were receiving carbamazepine (along with a variety of other drugs) and 16 were using several different drugs but not carbamazepine . The doses of vecuronium required for 50%, 90%, and 95% depression of first twitch were 29, 52, and 64 mcg/kg, respectively, for the carbamazepine group, compared with 21, 36, and 44 mcg/kg, respectively, for the non-carbamazepine group. Overall, a 40% higher dose of vecuronium was required in study subjects using carbamazepine.
B) A case report describes a 19-year old epileptic female who underwent a sigmoid colectomy . The patient had been maintained on carbamazepine 700 mg daily. The first bolus dose of vecuronium 6 mg produced relaxation for only 18 minutes. A continuous infusion of vecuronium at an average of 6.67 mg/hr was needed to sustain a complete neuromuscular block. This is higher than the average of vecuronium 4 mg/hr that is needed to produce block seen in patients not treated with carbamazepine.
C) The pharmacokinetic and pharmacodynamic effects of a bolus intravenous dose of vecuronium were studied in ten carbamazepine-treated subjects and in ten control subjects . No changes in onset time and volumes of distribution at steady-state were observed. However, the carbamazepine group had a shorter mean recovery time to 25% (T1 25%) compared to controls (28.1 minutes vs. 47.3 minutes). The T1 25% to T1 75% recovery index was 7.6 minutes in the carbamazepine group compared to 21.9 minutes in controls. Clearance of vecuronium was 9.0 mL/kg/min in the carbamazepine group and only 3.8 mL/kg/min in the control group. This two-fold increase in the clearance of vecuronium provides evidence of a pharmacokinetic origin to the interaction with carbamazepine, although the possibility of a concurrent pharmacodynamic interaction cannot be ruled out.
D) Long-term phenytoin or carbamazepine therapy accelerates recovery from vecuronium-induced paralysis in children. The patients were assigned to one of 3 groups: control (n=10; no history of epilepsy and not receiving chronic medication affecting neurotransmission), children receiving phenytoin (n=10) or carbamazepine (n=10). The elimination half-life was significantly shorter for the phenytoin and carbamazepine groups compared with control. A statistically significant increase in clearance of vecuronium occurred in the carbamazepine groups compared with control. Increased clearance of vecuronium in the phenytoin group also occurred but was not statistically significant. The recovery indices from vecuronium-induced block for the children on antiepileptic drugs were significantly faster than those for the control group. The author concludes that resistance to vecuronium in children on chronic anticonvulsant therapy is partly related to increased metabolism. The contribution of altered pharmacodynamics to the resistance to vecuronium could not be determined in this study .
Carbamazepine Overview
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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:
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.