Carbamazepine with Haloperidol Interaction Details
Brand Names Associated with Carbamazepine
- Carbamazepine
- Carbatrol®
- Epitol®
- Equetro®
- Tegretol®
- Tegretol®-XR
- Teril®
Brand Names Associated with Haloperidol
- Haldol®
- Haloperidol
Medical Content Editor Dr. Brian Staiger, PharmD
Last updated
Nov 25, 2023
Interaction Effect
Decreased haloperidol concentrations
Interaction Summary
Concomitant use of haloperidol and carbamazepine may result in a significant decrease in haloperidol plasma concentrations by 45% to 60% due to induction of CYP3A4-mediated metabolism by carbamazepine . A study of 11 patients with schizophrenia administered haloperidol together with increasing doses of carbamazepine resulted in a linear decrease of haloperidol concentrations as carbamazepine concentrations increased. Monitor the patient for a decreased clinical response to haloperidol when carbamazepine is added to the drug therapy. The haloperidol dose may need to be increased when starting carbamazepine and decreased when carbamazepine is discontinued .
Severity
Moderate
Onset
Unspecified
Evidence
Probable
How To Manage Interaction
Concomitant use of carbamazepine and haloperidol may result in a significant decrease in haloperidol plasma concentrations. Monitor the patient for a decreased clinical response to haloperidol when carbamazepine is added to the drug therapy. The haloperidol dose may need to be increased when starting carbamazepine and decreased when carbamazepine is discontinued .
Mechanism Of Interaction
Induction of CYP3A4-mediated haloperidol metabolism
Literature Reports
A) A study of 11 patients with schizophrenia administered haloperidol together with increasing doses of carbamazepine resulted in a linear decrease of haloperidol concentrations as carbamazepine concentrations increased .
B) Serum haloperidol levels of 7 patients treated for psychosis fell when carbamazepine was added to their therapy. Haloperidol doses ranged from 10 mg to 40 mg daily and carbamazepine doses ranged from 400 mg to 1000 mg daily. After carbamazepine was added, haloperidol levels decreased by a mean of 60%. The 2 patients whose blood levels fell to undetectable levels had a marked worsening of symptoms. Careful monitoring should take place if carbamazepine is added to haloperidol therapy .
C) Twenty-seven patients with schizophrenia enrolled in a study to determine the effects of carbamazepine and valproic acid on the plasma levels of haloperidol and the psychopathologic outcome. Following a 4-day washout period, patients were assigned to receive treatment for 4 weeks with haloperidol monotherapy, haloperidol with carbamazepine, or haloperidol with valproic acid. Doses of haloperidol remained stable throughout the study, and the doses of carbamazepine and valproic acid were titrated to a plasma level of 6 to 12 mg/L and 50 to 100 mg/L, respectively. When administered with carbamazepine, haloperidol plasma levels decreased by 45% (from 7.6 ng/mL to 4.6 ng/mL) over the 28-day period. Decreases in the rating scores on the Positive subscale of the Positive and Negative Syndrome Scale (pPANSS) were significant during the carbamazepine phase of the study, indicating that the coadministration of carbamazepine and haloperidol may worsen the clinical outcome compared to haloperidol monotherapy .
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.
Haloperidol Overview
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Haloperidol is used to treat psychotic disorders (conditions that cause difficulty telling the difference between things or ideas that are real and things or ideas that are not real). Haloperidol is also used to control motor tics (uncontrollable need to repeat certain body movements) and verbal tics (uncontrollable need to repeat sounds or words) in adults and children who have Tourette's disorder (condition characterized by motor or verbal tics). Haloperidol is also used to treat severe behavioral problems such as explosive, aggressive behavior or hyperactivity in children who cannot be treated with psychotherapy or with other medications. Haloperidol is in a group of medications called conventional antipsychotics. It works by decreasing abnormal excitement 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.