Venlafaxine with Trifluoperazine Interaction Details
Brand Names Associated with Venlafaxine
- Effexor®
- Effexor® XR
- Venlafaxine
Brand Names Associated with Trifluoperazine
- Stelazine®
- Trifluoperazine
Medical Content Editor Dr. Brian Staiger, PharmD
Last updated
Nov 12, 2023
Interaction Effect
An increased risk of neuroleptic malignant syndrome and an increased risk of cardiotoxicity (QT prolongation, torsades de pointes, cardiac arrest)
Interaction Summary
Q and T wave distortions have been observed in patients taking phenothiazines. Although citing no data, the manufacturers of some phenothiazines state that concomitant use with other drugs which prolong the QT interval is contraindicated . Venlafaxine has been shown to prolong the QTc interval at the recommended therapeutic dose . In addition, concomitant use of venlafaxine and trifluoperazine has resulted in neuroleptic malignant syndrome .
Severity
Contraindicated
Onset
Rapid
Evidence
Probable
How To Manage Interaction
The concurrent administration of venlafaxine and trifluoperazine is contraindicated.
Mechanism Of Interaction
Dopamine-inhibition effect of venlafaxine augments dopamine-receptor inhibition by trifluoperazine; additive effects on QT prolongation
Literature Reports
A) A 44-year-old male who had been receiving trifluoperazine 1 mg three times daily for ten years as an anxiolytic was prescribed venlafaxine 75 mg once daily for depression. Twelve hours following his first dose, he presented with profound sweating, anxiety, tremor, and rigidity. Vital signs revealed a blood pressure ranging from 130/80 mm Hg to 165/100 mm Hg and a pulse of 163 beats per minute. Urine and blood panels were within normal limits, with the exception of an elevated creatine phosphokinase concentration of 11,320 IU/L and a white-cell count of 23.5 x 10(9)/L. Neuroleptic malignant syndrome was diagnosed, and the patient was treated with dantrolene and bromocriptine. Within 24 hours the patient recovered completely. Trifluoperazine was reintroduced without complications. Neuroleptic malignant syndrome may have developed in this patient because of a pharmacodynamic interaction of a dopamine-inhibition effect induced by venlafaxine which augmented dopamine-receptor inhibition by trifluoperazine .
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.
Trifluoperazine Overview
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Trifluoperazine is used to treat the symptoms of schizophrenia (a mental illness that causes disturbed or unusual thinking, loss of interest in life, and strong or inappropriate emotions). Trifluoperazine is also used on a short-term basis to treat anxiety in people who have not been helped by other medications. Trifluoperazine 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.