Erlotinib and pantoprazole: a relevant interaction or not?
Rob Ter Heine1, James C Fanggiday, Nienke A G Lankheet
1Department of Pharmacy, Meander Medical Center, Amersfoort, the Netherlands. rob@terheine.nl
British Journal of Clinical Pharmacology
|December 24, 2010
Summary
Therapeutic drug monitoring revealed that high-dose intravenous pantoprazole reduced erlotinib levels. Oral pantoprazole at lower doses allowed erlotinib concentrations to normalize, suggesting a pH-dependent interaction.
Area of Science:
- Oncology
- Pharmacology
- Gastroenterology
Background:
- Erlotinib exposure is linked to treatment outcomes in cancer therapy.
- Proton pump inhibitors (PPIs) like pantoprazole can alter gastric pH.
- Gastric pH affects the absorption of pH-dependent drugs such as erlotinib.
Observation:
- This case report details therapeutic drug monitoring of erlotinib.
- A patient with a gastric ulcer was treated with both erlotinib and pantoprazole.
- Erlotinib trough concentrations were measured during oral and intravenous pantoprazole administration.
Findings:
- High-dose intravenous pantoprazole administration led to diminished erlotinib trough concentrations.
- Reducing the pantoprazole dose and switching to oral administration resulted in normalized erlotinib levels.
- This indicates a potential drug interaction influenced by pantoprazole's administration route and dosage.
Implications:
- Further research is required to understand the dose-dependent interaction between pantoprazole and erlotinib.
- Close monitoring of erlotinib plasma concentrations is advised when co-administering with pantoprazole.
- Dose adjustments for erlotinib may be necessary to ensure therapeutic efficacy in the presence of this interaction.
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