Omeprazole interactions
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Omeprazole Interactions: A Comprehensive Overview
Introduction to Omeprazole and Its Uses
Omeprazole is a widely used proton pump inhibitor (PPI) for treating conditions like dyspepsia, peptic ulcer, gastroesophageal reflux disease, and functional dyspepsia. However, its extensive use, especially in polypharmacy scenarios, raises concerns about potential drug-drug interactions (DDIs)1.
Mechanisms of Omeprazole Drug Interactions
Cytochrome P450 Enzyme System
Omeprazole can interfere with the metabolism of other drugs by altering the activity of the cytochrome P450 enzyme system. It has been shown to inhibit the metabolism of drugs metabolized by the CYP2C19 enzyme, such as diazepam and phenytoin, but not those metabolized by CYP1A2, CYP2D6, or CYP3A42 4. This inhibition can lead to increased plasma levels of these drugs, potentially causing adverse effects.
Gastric pH Alteration
Omeprazole increases gastric pH, which can affect the absorption of drugs that require an acidic environment for optimal absorption. For instance, the absorption of digoxin and nifedipine is increased, while the absorption of drugs like ketoconazole and iron supplements is decreased1 4.
Specific Drug Interactions
Antiretrovirals and Antimicrobials
Omeprazole has significant interactions with antiretrovirals such as indinavir, nelfinavir, and atazanavir, leading to reduced efficacy of these drugs1. Additionally, when combined with clarithromycin, omeprazole levels can increase almost two-fold, which may enhance its therapeutic effects but also raise the risk of side effects3.
Non-Steroidal Anti-Inflammatory Drugs (NSAIDs)
Studies have shown that omeprazole does not significantly alter the pharmacokinetics of NSAIDs like diclofenac, naproxen, and piroxicam, indicating that these drugs can be co-administered without dosage adjustments6.
Hepatitis C Virus (HCV) Protease Inhibitors
Research indicates that omeprazole does not have a clinically significant effect on the pharmacokinetics of the HCV protease inhibitor boceprevir, suggesting that these drugs can be used together safely5.
Immunosuppressants
Omeprazole does not significantly affect the metabolism of cyclosporine in renal transplant patients, making it a safe option for use in this population without the need for additional monitoring9.
Factors Influencing Drug Interactions
Genetic Variability
The degree of DDIs associated with omeprazole can depend on genetic factors such as the genotype status of CYP2C19 and CYP1A2. Ethnicity, dose, treatment course, and the pharmaceutical formulation of the co-administered drug also play crucial roles1.
Alternative PPIs
In cases where omeprazole interactions pose significant risks, other PPIs or histamine 2 antagonists may be considered as therapeutic alternatives to avoid adverse consequences1.
Conclusion
Omeprazole, while effective for treating various acid-related conditions, has a complex interaction profile that necessitates careful consideration in polypharmacy settings. Clinicians should be aware of its potential to alter the pharmacokinetics of co-administered drugs, particularly those metabolized by CYP2C19, and manage these interactions through appropriate monitoring and alternative therapies when necessary.
Sources and full results
Most relevant research papers on this topic
Pharmacokinetic drug interaction profile of omeprazole with adverse consequences and clinical risk management
Omeprazole can cause adverse drug interactions with various medications, requiring enhanced clinical risk management to avoid adverse consequences.
Systematic Review
Rigorous Journal
Highly CitedOmeprazole Drug Interaction Studies
Omeprazole may partially inhibit the metabolism of drugs metabolized by cytochrome P450 subfamily IIC, but not those metabolized by subfamilies IA, IID, and IIIA.
Literature ReviewHighly CitedPharmacokinetic interactions between omeprazole/pantoprazole and clarithromycin in health volunteers.
Clarithromycin can significantly increase omeprazole levels, potentially improving therapeutic response but potentially affecting CYP3A4 metabolism or interfering with drug absorption.
RCTDrug Interaction Studies with Esomeprazole, the (S)-Isomer of Omeprazole
Esomeprazole has low potential for drug-drug interactions, similar to omeprazole, with minor effects on diazepam, phenytoin, (R)-warfarin, and cisapride.
Highly CitedLack of a clinically significant drug-drug interaction in healthy volunteers between the HCV protease inhibitor boceprevir and the proton pump inhibitor omeprazole.
Omeprazole does not significantly affect boceprevir exposure, and boceprevir does not significantly affect omeprazole exposure in healthy volunteers.
RCTLack of drug-drug interaction between three different non-steroidal anti-inflammatory drugs and omeprazole
Diclofenac, naproxen, and piroxicam can be administered together with omeprazole 20 mg daily without needing dosage alteration or significant change in their bioavailability.
RCTThe interaction of omeprazole with rat liver cytochrome P450-mediated monooxygenase reactions in vitro and in vivo.
Omeprazole interacts with the mixed function oxidase system in rat liver, decreasing diazepam clearance and increasing liver weight, cytochrome P450, and ECOD activity in vivo.
In Vitro StudyThe pharmacokinetic (PK) interaction between omeprazole and TMC278, an investigational non-nucleoside reverse transcriptase inhibitor (NNRTI)
Omeprazole increases gastric pH, which may affect the solubility and gastro-intestinal absorption of TMC278, and TMC278 may induce CYP2C19, potentially influencing omeprazole's pharmacokinetics.
Non-RCTRigorous JournalA study of the interaction between omeprazole and cyclosporine in renal transplant patients.
Omeprazole (20 mg daily) does not significantly interfere with cyclosporine A metabolism in stabilized renal transplant patients and can be used safely without extra monitoring of blood CsA concentrations.
RCT