Venlafaxine with Cimetidine Interaction Details
Brand Names Associated with Venlafaxine
- Effexor®
- Effexor® XR
- Venlafaxine
Brand Names Associated with Cimetidine
- Cimetidine
- Tagamet®
- Tagamet® HB
Medical Content Editor Dr. Brian Staiger, PharmD
Last updated
Nov 12, 2023
Interaction Effect
An increased risk of venlafaxine toxicity (nausea, drowsiness, dizziness, ejaculatory disturbances)
Interaction Summary
Concurrent administration of cimetidine and venlafaxine (both at steady state) resulted in a 43% reduction in the oral clearance of venlafaxine and a 60% increase in the AUC and peak concentration of venlafaxine. The major metabolite, O-desmethylvenlafaxine, was unaffected by cimetidine, and is present in much greater amounts in the circulation than the parent drug. Because of this, it is unlikely that a clinically significant interaction will occur with this combination. However, this interaction could be more pronounced in patients with preexisting hepatic or renal dysfunction . Therefore, caution is advised when cimetidine and venlafaxine are coadministered, particularly in patients with preexisting hepatic or renal function .
Severity
Minor
Onset
Delayed
Evidence
Probable
How To Manage Interaction
Concomitant use of cimetidine and venlafaxine may result in decreased venlafaxine clearance. Therefore, patients should be monitored for signs of venlafaxine toxicity such as nausea, drowsiness, and dizziness; a decrease in dosage may be required with concomitant therapy. An alternative H-2 blocker that has not been reported to impair the metabolism of venlafaxine, such as ranitidine or famotidine, may be an alternative.
Mechanism Of Interaction
Decreased venlafaxine clearance
Literature Reports
A) Eighteen healthy volunteers received venlafaxine 50 mg three times daily for five days alone and in combination with cimetidine 800 mg daily to determine the influence of cimetidine on the pharmacokinetics of venlafaxine. Venlafaxine has pharmacologic activity, and the metabolite O-desmethylvenlafaxine possesses approximately equimolar activity as the parent compound. When cimetidine was coadministered, the average steady-state concentration of venlafaxine increased from a mean of 105 ng/mL to 169 ng/mL. However, the mean steady-state concentration of O-desmethylvenlafaxine did not change in the presence of cimetidine (388 ng/mL vs. 387 ng/mL). Therefore, the sum of the plasma concentrations of venlafaxine and O-desmethylvenlafaxine increased by an average of 13%. This increase is not expected to produce clinically significant alterations in the response to venlafaxine in depressed patients without hepatic or renal dysfunction .
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.
Cimetidine Overview
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Cimetidine is used to treat ulcers; gastroesophageal reflux disease (GERD), a condition in which backward flow of acid from the stomach causes heartburn and injury of the food pipe (esophagus); and conditions where the stomach produces too much acid, such as Zollinger-Ellison syndrome. Over-the-counter cimetidine is used to prevent and treat symptoms of heartburn associated with acid indigestion and sour stomach. Cimetidine is in a class of medications called H2 blockers. It decreases the amount of acid made in the stomach.
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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.