Omeprazole interactions with other drugs
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Omeprazole Interactions with Other Drugs
Introduction to Omeprazole and Its Uses
Omeprazole, a proton pump inhibitor (PPI), is commonly prescribed for conditions such as dyspepsia, peptic ulcer, gastroesophageal reflux disease, and functional dyspepsia. Given its widespread use, understanding its interactions with other drugs is crucial for ensuring patient safety and treatment efficacy1.
Mechanisms of Drug Interactions with Omeprazole
Omeprazole can interact with other drugs through several mechanisms. These include altering drug absorption due to changes in gastric pH, inhibiting or inducing cytochrome P450 enzymes, and affecting drug transport proteins like P-glycoprotein1 2. These interactions can lead to either increased toxicity or reduced efficacy of the co-administered drugs.
Interactions with Specific Drugs
Antiretrovirals and Antifungals
Omeprazole has been shown to affect the pharmacokinetics of several antiretroviral drugs, including indinavir, nelfinavir, atazanavir, and rilpivirine, potentially leading to reduced efficacy of these medications1. Similarly, it can alter the absorption of antifungal agents like itraconazole and posaconazole, which rely on an acidic environment for optimal absorption1.
Antiepileptics and Psychotropics
The metabolism of drugs such as diazepam, carbamazepine, and clozapine can be inhibited by omeprazole, leading to increased plasma levels and potential toxicity1 2. This is primarily due to the inhibition of the cytochrome P450 enzyme CYP2C19 by omeprazole.
Cardiovascular Drugs
Omeprazole can interact with clopidogrel, a commonly used antiplatelet drug, by inhibiting CYP2C19, which is necessary for converting clopidogrel into its active form. This interaction can reduce the effectiveness of clopidogrel, increasing the risk of cardiovascular events5 7. Additionally, omeprazole can increase the absorption of digoxin, although this increase is generally not clinically significant2.
NSAIDs and Chemotherapeutics
Studies have shown that omeprazole does not significantly affect the pharmacokinetics of non-steroidal anti-inflammatory drugs (NSAIDs) like diclofenac, naproxen, and piroxicam, indicating that these drugs can be safely co-administered with omeprazole without dosage adjustments4. However, omeprazole does not alter the pharmacokinetics or toxicities of irinotecan, a chemotherapeutic agent, suggesting it can be safely used in cancer patients undergoing irinotecan treatment10.
Herbal Medicines
Herbal medicines such as St John’s wort, Ginkgo biloba, and yin zhi huang can induce the metabolism of omeprazole, leading to reduced efficacy of the PPI1. This is due to the induction of cytochrome P450 enzymes, which increases the elimination of omeprazole from the body.
Clinical Risk Management
Given the potential for significant drug interactions, clinical professionals should carefully manage the use of omeprazole in patients taking multiple medications. This includes considering alternative PPIs or histamine 2 antagonists, checking the appropriateness of physician orders, and performing therapeutic drug monitoring1. Factors such as the patient's genotype status of CYP2C19 and CYP1A2, ethnicity, and the specific pharmaceutical formulation of the co-administered drug should also be taken into account1.
Conclusion
Omeprazole, while effective for treating various acid-related disorders, has a significant potential for drug interactions that can impact the efficacy and safety of other medications. Understanding these interactions and managing them appropriately is essential for optimizing patient outcomes and minimizing adverse effects.
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 JournalOmeprazole 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 Review
Highly CitedDrug 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 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.
RCTPharmacokinetic Drug Interaction Profiles of Proton Pump Inhibitors: An Update
Proton pump inhibitors (PPIs) can cause drug interactions, particularly with clopidogrel, but only a few are clinically significant.
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.
RCTDifferential Effects of Omeprazole and Pantoprazole on the Pharmacodynamics and Pharmacokinetics of Clopidogrel in Healthy Subjects: Randomized, Placebo‐Controlled, Crossover Comparison Studies
A metabolic drug-drug interaction exists between clopidogrel and omeprazole, but not between clopidogrel and pantoprazole, with no significant differences observed between the two drugs.
RCTRigorous JournalHighly CitedMetabolic interactions of the proton-pump inhibitors lansoprazole, omeprazole and pantoprazole with other drugs
Pantoprazole has the lowest potential for drug interactions among proton-pump inhibitors, as it is metabolized by a sulfotransferase, which may explain its low potential for drug interactions.
In Vitro StudyHighly CitedOmeprazole: pharmacology, pharmacokinetics and interactions.
Omeprazole effectively inhibits gastric acid secretion, with a complex pharmacokinetic profile and minimal impact on drug interactions, except for diazepam.
Effect of omeprazole on the pharmacokinetics and toxicities of irinotecan in cancer patients: a prospective cross-over drug-drug interaction study.
Omeprazole 40mg does not alter the pharmacokinetics or toxicities of irinotecan, making it safe to administer during a 3-weekly single agent irinotecan schedule.
Non-RCT
Very Rigorous Journal