Capecitabine with Cimetidine Interaction Details
Brand Names Associated with Capecitabine
- Capecitabine
- Xeloda®
Brand Names Associated with Cimetidine
- Cimetidine
- Tagamet®
- Tagamet® HB
Medical Content Editor Dr. Brian Staiger, PharmD
Last updated
Dec 22, 2023
Interaction Effect
An increased risk of fluorouracil toxicity
Interaction Summary
Concomitant fluorouracil and cimetidine therapy has resulted in increased peak plasma levels and area under the plasma concentration-time curve (AUC) for fluorouracil, and coadministration of cimetidine with fluorouracil or one of its prodrugs should be approached with caution .
Severity
Major
Onset
Delayed
Evidence
Probable
How To Manage Interaction
Monitor patients who have received long-term (four or more weeks) therapy with cimetidine for an increased incidence of adverse effects to fluorouracil. If possible, discontinue the cimetidine prior to the administration of fluorouracil or a product containing a prodrug of fluorouracil. An alternative H-2 antagonist could also be substituted for cimetidine.
Mechanism Of Interaction
Inhibition of fluorouracil metabolism
Literature Reports
A) Concomitant oral 5-fluorouracil and cimetidine therapy resulted in increased peak plasma levels and area under the plasma concentration-time curve (AUC) for 5-fluorouracil in 15 ambulant patients with carcinoma. These effects were observed after doses of cimetidine 1 gram daily for 4 weeks, but a single pretreatment dose of cimetidine 400 mg or daily doses of 1 g for 1 week did not alter the pharmacokinetics of fluorouracil. Similarly, the AUC for intravenous 5-fluorouracil was significantly increased following 4 weeks of cimetidine pretreatment .
Capecitabine Overview
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Capecitabine is used in combination with other medications to treat breast cancer that has come back after treatment with other medications. It is also used alone to treat breast cancer that has not improved after treatment with other medications. Capecitabine is also used to treat colon or rectal cancer (cancer that begins in the large intestine) that has gotten worse or spread to other parts of the body. It is also used to prevent colon cancer from spreading in people who have had surgery to remove the tumor. Capecitabine is in a class of medications called antimetabolites. It works by stopping or slowing the growth of cancer cells.
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.