Venlafaxine with Haloperidol Interaction Details
Brand Names Associated with Venlafaxine
- Effexor®
- Effexor® XR
- Venlafaxine
Brand Names Associated with Haloperidol
- Haldol®
- Haloperidol
Medical Content Editor Dr. Brian Staiger, PharmD
Last updated
Nov 12, 2023
Interaction Effect
Increased haloperidol serum concentrations and an increased risk of cardiotoxicity (QT prolongation, torsades de pointes, cardiac arrest)
Interaction Summary
Venlafaxine may inhibit haloperidol metabolism. Haloperidol is associated with QTc prolongation and torsade de pointes . Venlafaxine has been shown to prolong the QTc interval at the recommended therapeutic dose . Concomitant use is not recommended.
Severity
Major
Onset
Rapid
Evidence
Probable
How To Manage Interaction
The concurrent administration of haloperidol and venlafaxine is not recommended.
Mechanism Of Interaction
Decreased haloperidol metabolism; theoretical additive effect on QT prolongation
Literature Reports
A) Under steady-state conditions, venlafaxine 150 mg daily decreased the total oral clearance of a single 2 mg dose of haloperidol by 42% in 24 healthy subjects. This resulted in a 70% increase in the haloperidol area under the concentration-time curve (AUC). The haloperidol maximum concentration (Cmax) was increased by 88% when venlafaxine was coadministered, but the elimination half-life of haloperidol was not affected. The mechanism behind this interaction is not known .
B) Numerous case reports have described significant QTc prolongation and torsades de pointes (TdP) associated with haloperidol. Hemodynamically significant ventricular tachyarrhythmias, ventricular fibrillation, asystole, and death have been reported. The risk of TdP appears to be greater with intravenous haloperidol, but has occurred with oral and intramuscular use. The risk increases with doses greater than 35 milligrams (mg) over 24 hours, although TdP has been associated with a dose as low as 10 mg administered intravenously over 4 hours. To prevent haloperidol-induced TdP, screen patients for a history of dilated cardiomyopathy or alcohol abuse, testing for hypothyroidism before therapy, obtaining an electrocardiogram at baseline and throughout therapy, and monitoring potassium, magnesium, and calcium. In patients with a baseline QTc greater than 450 milliseconds (msec), haloperidol should be used cautiously or an alternative agent should be used. Discontinue haloperidol if the QTc increases more than 25% from baseline or if flattening of T-waves or development of U-waves occurs .
Venlafaxine Overview
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Venlafaxine is used to treat depression. Venlafaxine extended-release (long-acting) capsules are also used to treat generalized anxiety disorder (GAD; excessive worrying that is difficult to control), social anxiety disorder (extreme fear of interacting with others or performing in front of others that interferes with normal life), and panic disorder (sudden, unexpected attacks of extreme fear and worry about these attacks). Venlafaxine is in a class of medications called selective serotonin and norepinephrine reuptake inhibitors (SNRIs). It works by increasing the amounts of serotonin and norepinephrine, natural substances in the brain that help maintain mental balance.
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.