Omeprazole (Page 4 of 15)

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 Delayed-Release Capsules 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 C li n i cal P harmacology ( 12.3)] .

  • Increased exposure of other antiretroviral drugs (e.g., saquinavir) when used concomitantly with omeprazole may increase toxicity [see C l i n i cal P harmacology ( 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 Capsules is contraindicated [see C o ntraindications ( 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 W arnings and Precautions ( 5.11)].

Intervention: A temporary withdrawal of Omeprazole Delayed-Release Capsules 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 C li n i cal P harmacology ( 12.3)] .

.
Intervention:

Avoid concomitant use with Omeprazole Delayed-Release Capsules. Consider use of alternative anti-platelet therapy

[see W arnings and Precautions ( 5.6)].
Citalopram
Clinical Impact:

Increased exposure of citalopram leading to an increased risk of QT prolongation [ see C li n i cal 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 C l i nical 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 C l i nical 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 C l i n i c al Pharmacology ( 12.3)].
Intervention:

Monitor digoxin concentrations. Dose adjustment may be needed to maintain therapeutic drug concentrations. See digoxin prescribing information.

D rugs 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

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 C l i nical P harmacology ( 12.3)] .

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.

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 W arnings and Precautions ( 5.10), C li n i cal P harmacology ( 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 Cl i n i cal 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 Delayed-Release Capsules 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 Delayed-Release Capsules [ see W arnings and P recautions ( 5.9)] .

Ritonavir-containing products: see prescribing information for specific drugs.
CYP2C19 or CYP3A4 Inhibitors
Clinical Impact: Increased exposure of omeprazole [see C l i n i cal Pharmacology ( 12.3)].
Intervention:

Voriconazole: Dose adjustment of Omeprazole Delayed-Release Capsules is not normally required. However, in patients with Zollinger-Ellison syndrome, who may require higher doses, dose adjustment may be considered.


All MedLibrary.org resources are included in as near-original form as possible, meaning that the information from the original provider has been rendered here with only typographical or stylistic modifications and not with any substantive alterations of content, meaning or intent.

This site is provided for educational and informational purposes only, in accordance with our Terms of Use, and is not intended as a substitute for the advice of a medical doctor, nurse, nurse practitioner or other qualified health professional.

Privacy Policy | Copyright © 2020. All Rights Reserved.