atazanavir and omeprazole: what the product label says

The product label for omeprazole names atazanavir in its drug-interaction information. The complete selected section is reproduced below so that qualifications stay with the finding.

Which products this evidence covers

Omeprazole — CAPSULE, DELAYED RELEASE — ORAL

Labeled active ingredients: OMEPRAZOLE. Routes: ORAL. Dosage forms: CAPSULE, DELAYED RELEASE.

Supporting label passage

Section: 7 DRUG INTERACTIONS

Tables 3 and 4 include drugs with clinically important drug interactions and interaction with diagnostics when administered concomitantly with Omeprazole delayed-release capsules and instructions for preventing or managing them. Consult the labeling of concomitantly used drugs to obtain further information about interactions with PPIs. Table 3 Clinically Relevant Interactions Affecting Drugs Co-Administered with Omeprazole and Interaction with Diagnostics Antiretrovirals Clinical Impact The effect of PPIs on antiretroviral drugs is variable. The clinical importance and the mechanisms behind these interactions are not always known. • Decreased exposure of some antiretroviral drugs (e.g., rilpivirine, atazanavir and nelfinavir) when used concomitantly with omeprazole may reduce antiviral effect and promote the development of drug resistance [see Clinical Pharmacology ( 12.3 )]. • Increased exposure of other antiretroviral drugs (e.g., saquinavir) when used concomitantly with omeprazole may increase toxicity [see clinical Pharmacology ( 12.3 )]. • There are other antiretroviral drugs which do not result in clinically relevant interactions with omeprazole. Intervention Rilpivirine-containing products: Concomitant use with omeprazole delayed-release capsule is contraindicated [see Contraindications ( 4 )]. Atazanavir: Avoid concomitant use with omeprazole delayed-release capsules. See prescribing information for atazanavir for dosing information. Nelfinavir: Avoid concomitant use with omeprazole delayed-release capsules. See prescribing information for nelfinavir. Saquinavir: See the prescribing information for saquinavir for monitoring of potential saquinavir-related toxicities. Other antiretrovirals: See prescribing information for specific antiretroviral drugs. Warfarin Clinical Impact Increased INR and prothrombin time in patients receiving PPIs, including omeprazole, and warfarin concomitantly. Increases in INR and prothrombin time may lead to abnormal bleeding and even death. Intervention Monitor INR and prothrombin time and adjust the dose of warfarin, if needed, to maintain target INR range. Methotrexate Clinical Impact Concomitant use of omeprazole with methotrexate (primarily at high dose) may elevate and prolong serum concentrations of methotrexate and/or its metabolite hydroxymethotrexate, possibly leading to methotrexate toxicities. No formal drug interaction studies of high-dose methotrexate with PPIs have been conducted [see Warnings and Precautions ( 5.11 )]. Intervention A temporary withdrawal of omeprazole may be considered in some patients receiving high-dose methotrexate. CYP2C19 Substrates (e.g., clopidogrel, citalopram, cilostazol, phenytoin, diazepam) Clopidogrel Clinical Impact Concomitant use of omeprazole 80 mg results in reduced plasma concentrations of the active metabolite of clopidogrel and a reduction in platelet inhibition [see Clinical Pharmacology ( 12.3 )]. There are no adequate combination studies of a lower dose of omeprazole or a higher dose of clopidogrel in comparison with the approved dose of clopidogrel . Intervention Avoid concomitant use with omeprazole delayed-release capsules. Consider use of alternative anti-platelet therapy [see Warnings and Precautions ( 5.6) ]. Citalopram Clinical Impact Increased exposure of citalopram leading to an increased risk of QT prolongation [see Clinical Pharmacology ( 12.3 )] . Intervention Limit the dose of citalopram to a maximum of 20 mg per day. See prescribing information for citalopram. Cilostazol Clinical Impact Increased exposure of one of the active metabolites of cilostazol (3,4-dihydro-cilostazol) [see Clinical Pharmacology ( 12.3 )]. Intervention Reduce the dose of cilostazol to 50 mg twice daily. See prescribing information for cilostazol. Phenytoin Clinical Impact Potential for increased exposure of phenytoin. Intervention Monitor phenytoin serum concentrations. Dose adjustment may be needed to maintain therapeutic drug concentrations. See prescribing information for phenytoin. Diazepam Clinical Impact Increased exposure of diazepam [see Clinical Pharmacology ( 12.3 )] . Intervention Monitor patients for increased sedation and reduce the dose of diazepam as needed. Digoxin Clinical Impact Potential for increased exposure of digoxin [see Clinical Pharmacology ( 12.3 )]. Intervention Monitor digoxin concentrations. Dose adjustment may be needed to maintain therapeutic drug concentrations. See digoxin prescribing information. Drugs Dependent on Gastric pH for Absorption (e.g., iron salts, erlotinib, dasatinib, nilotinib, mycophenolate mofetil, ketoconazole/itraconazole) Clinical Impact Omeprazole can reduce the absorption of other drugs due to its effect on reducing intragastric acidity. Intervention Mycophenolate mofetil (MMF): Co-administration of omeprazole in healthy subjects and in transplant patients receiving MMF has been reported to reduce the exposure to the active metabolite, mycophenolic acid (MPA), possibly due to a decrease in MMF solubility at an increased gastric pH. The clinical relevance of reduced MPA exposure on organ rejection has not been established in transplant patients receiving omeprazole delayed-release capsules and MMF. Use omeprazole delayed-release capsules with caution in transplant patients receiving MMF [see Clinical Pharmacology ( 12.3 )] . See the prescribing information for other drugs dependent on gastric pH for absorption. Combination Therapy with Clarithromycin and Amoxicillin Clinical Impact Concomitant administration of clarithromycin with other drugs can lead to serious adverse reactions, including potentially fatal arrhythmias, and are contraindicated. Amoxicillin also has drug interactions. Intervention See Contraindications, Warnings and Precautions in prescribing information for clarithromycin. See Drug Interactions in prescribing information for amoxicillin. Tacrolimus Clinical Impact Potential for increased exposure of tacrolimus, especially in transplant patients who are intermediate or poor metabolizers of CYP2C19 . Intervention Monitor tacrolimus whole blood concentrations. Dose adjustment may be needed to maintain therapeutic drug concentrations. See prescribing information for tacrolimus. Interactions with Investigations of Neuroendocrine Tumors Clinical Impact Serum chromogranin A (CgA) levels increase secondary to PPI-induced decreases in gastric acidity. The increased CgA level may cause false positive results in diagnostic investigations for neuroendocrine tumors [see Warnings and Precautions ( 5.10 ), Clinical Pharmacology ( 12.2 )] . Intervention Temporarily stop omeprazole delayed-release capsules treatment at least 14 days before assessing CgA levels and consider repeating the test if initial CgA levels are high. If serial tests are performed (e.g., for monitoring), the same commercial laboratory should be used for testing, as reference ranges between tests may vary. Interaction with Secretin Stimulation Test Clinical Impact Hyper-response in gastrin secretion in response to secretin stimulation test, falsely suggesting gastrinoma. Intervention Temporarily stop omeprazole delayed-release capsules treatment at least 14 days before assessing to allow gastrin levels to return to baseline [see Clinical Pharmacology ( 12.2 )] . False Positive Urine Tests for THC Clinical Impact There have been reports of false positive urine screening tests for tetrahydrocannabinol (THC) in patients receiving PPIs. Intervention An alternative confirmatory method should be considered to verify positive results. Other Clinical Impact There have been clinical reports of interactions with other drugs metabolized via the cytochrome P450 system (e.g., cyclosporine, disulfiram). Intervention Monitor patients to determine if it is necessary to adjust the dosage of these other drugs when taken concomitantly with omeprazole delayed-release capsules. Table 4 Clinically Relevant Interactions Affecting Omeprazole When Co-Administered with Other Drugs CYP2C19 or CYP3A4 Inducers Clinical Impact Decreased exposure of omeprazole when used concomitantly with strong inducers [see Clinical Pharmacology ( 12.3 )]. Intervention St. John's Wort, rifampin: Avoid concomitant use with omeprazole [see Warnings And Precautions ( 5.9 )]. Ritonavir-containing products: see prescribing information for specific drugs. CYP2C19 or CYP3A4 Inhibitors Clinical Impact Increased exposure of omeprazole [see Clinical Pharmacology ( 12.3 )]. Intervention Voriconazole: Dose adjustment of omeprazole is not normally required. However, in patients with Zollinger-Ellison syndrome, who may require higher doses, dose adjustment may be considered. See prescribing information for voriconazole.

Read the full product label on DailyMed. Label version 9, dated 2026-10-27.

Limits of this evidence

This passage applies to the labeled product and circumstances it describes. It must not be generalized to other routes or formulations. It does not independently validate CDI’s severity category, establish safety for an individual, or replace the full label. The stored interaction description and classification have not been changed by this article.

How this brief was prepared

Automatic checks matched drug identities, retrieved and preserved the label, and checked the full quoted section with AI assistance on 2026-11-10. The public explanation uses a fixed template; model-written medical advice is not published. Independent clinical review has not been recorded.

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