Fluconazole with Cimetidine Interaction Details
Brand Names Associated with Fluconazole
- Diflucan®
- Fluconazole
Brand Names Associated with Cimetidine
- Cimetidine
- Tagamet®
- Tagamet® HB
Medical Content Editor Dr. Brian Staiger, PharmD
Last updated
Nov 27, 2023
Interaction Effect
Decreased fluconazole effectiveness
Interaction Summary
Concomitant use of cimetidine 400 mg and fluconazole resulted in a decreased peak fluconazole level by about 20% in six healthy volunteers. In a more alkaline gastrointestinal tract, as with AIDS patients, ketoconazole has been reported to also be slightly less absorbed .
Severity
Moderate
Onset
Delayed
Evidence
Probable
How To Manage Interaction
Concurrent administration of fluconazole and cimetidine is not recommended. If concurrent use cannot be avoided, cimetidine should be taken at least two hours after fluconazole. Because staggered administration may not be completely reliable, aggressively monitor these patients for continued antifungal efficacy.
Mechanism Of Interaction
Decreased gastrointestinal absorption
Literature Reports
A) Single oral dose administration of fluconazole 100 mg with cimetidine 400 mg to six healthy volunteers resulted in a 13% decrease in fluconazole area under the plasma concentration-time curve (AUC) and a 19% decrease in maximum serum fluconazole concentration (Cmax). However, the administration of cimetidine 600 to 900 mg intravenously over a period of four hours did not affect the pharmacokinetics or bioavailability of a single 200 mg oral dose of fluconazole in 24 healthy male volunteers .
Fluconazole Overview
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Fluconazole is used to treat fungal infections, including yeast infections of the vagina, mouth, throat, esophagus (tube leading from the mouth to the stomach), abdomen (area between the chest and waist), lungs, blood, and other organs. Fluconazole is also used to treat meningitis (infection of the membranes covering the brain and spine) caused by fungus. Fluconazole is also used to prevent yeast infections in patients who are likely to become infected because they are being treated with chemotherapy or radiation therapy before a bone marrow transplant (replacement of unhealthy spongy tissue inside the bones with healthy tissue). Fluconazole is in a class of antifungals called triazoles. It works by slowing the growth of fungi that cause infection.
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.