Erlotinib with Cimetidine Interaction Details
Brand Names Associated with Erlotinib
- Erlotinib
- Tarceva®
Brand Names Associated with Cimetidine
- Cimetidine
- Tagamet®
- Tagamet® HB
Medical Content Editor Dr. Brian Staiger, PharmD
Last updated
Dec 18, 2023
Interaction Effect
Reduced erlotinib exposure
Interaction Summary
The solubility of erlotinib is pH dependent and decreases as pH increases. Concomitant use of erlotinib and a histamine-2 receptor antagonists (ranitidine or famotidine) has decreased erlotinib solubility and exposure in 2 pharmacokinetic studies . However, the effects on erlotinib exposure were minimized when ranitidine and erlotinib administration were staggered . If coadministration of erlotinib with a histamine-2 (H2) receptor antagonist is required, adjust the dosing schedule rather than increasing the erlotinib dosage, which would not compensate for loss of exposure. Administer erlotinib 10 hours after receiving a dose of the H2-receptor antagonist and at least 2 hours before the next H2-receptor antagonist dose .
Severity
Major
Onset
Unspecified
Evidence
Established
How To Manage Interaction
The solubility of erlotinib is pH dependent and decreases as pH increases. Concomitant use of erlotinib and drugs that increase the gastric pH, such as a histamine-2 (H2) receptor antagonists, may decrease erlotinib solubility and decrease exposure. If coadministered, adjust the dosing schedule rather than increasing the erlotinib dosage, which would not compensate for loss of exposure. Administer erlotinib 10 hours after receiving a dose of the H2-receptor antagonist and at least 2 hours before the next H2-receptor antagonist dose.
Mechanism Of Interaction
PH-related reduction in erlotinib solubility and subsequent reduction in absorption
Literature Reports
A) Coadministration of erlotinib and histamine-2 receptor antagonists (n=6) compared with patients receiving only erlotinib (n=24) resulted in a nonsignificant decrease in the plasma-to-dose ratio of erlotinib (0.48 vs 0.51 mcg/[mL x mg x kg]) and increase in erlotinib oral clearance (4.82 vs 3.95 L/hr) in a pharmacokinetic study of patients receiving erlotinib for treatment of non-small cell lung cancer. Histamine-2 receptor antagonists included famotidine (n=4) or ranitidine (n=2) .
B) In a pharmacokinetic study (N=24), administration of erlotinib 150 mg 2 hours after ranitidine 300 mg once daily resulted in significantly reduced erlotinib AUC by 33% and Cmax by 54% compared with erlotinib alone. When erlotinib was given 10 hours after ranitidine 150 mg twice daily and 2 hours prior to the next ranitidine dose, the erlotinib AUC and Cmax decreased by 15% and 17%, respectively. Exposure to the major active metabolite, OSI-420, was similarly effected in both ranitidine dosing regimens .
Erlotinib Overview
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Erlotinib is used to treat certain types of non-small cell lung cancer that has spread to nearby tissues or to other parts of the body in patients who have already been treated with at least one other chemotherapy medication and have not gotten better. Erlotinib is also used in combination with another medication (gemcitabine [Gemzar]) to treat pancreatic cancer that has spread to nearby tissues or to other parts of the body and cannot be treated with surgery. Erlotinib is in a class of medications called kinase inhibitors. It works by blocking the action of an abnormal protein that signals cancer cells to multiply. This helps slow or stop the spread 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.