Omeprazole with Diazepam Interaction Details

Brand Names Associated with Omeprazole

Brand Names Associated with Diazepam

Medical Content Editor Dr. Brian Staiger, PharmD
Last updated Nov 19, 2023

Interaction Effect

Increased diazepam exposure

Interaction Summary

Concomitant administration of omeprazole with diazepam may increase the exposure of diazepam. Monitor patients for increased sedation and reduce the dose of diazepam as needed. Concurrent use of diazepam and omeprazole has been reported to slow diazepam metabolism and delay its elimination, thereby resulting in enhanced and prolonged benzodiazepine effects . One study indicated that decreased diazepam clearance occurred in almost one-half of patients who were fast metabolizers of omeprazole but the combination had little significance in slow metabolizers of omeprazole .

Severity

Major

Onset

Delayed

Evidence

Probable

How To Manage Interaction

Concomitant administration of omeprazole with diazepam may increase the exposure of diazepam. Monitor patients for increased sedation and reduce the dose of diazepam as needed.

Mechanism Of Interaction

Inhibition of CYP2C19-mediated metabolism of diazepam

Literature Reports

A) Concomitant administration of omeprazole 20 mg once daily and diazepam 0.1 mg/kg given intravenously resulted in 27% decrease in clearance and 36% increase in diazepam half-life .

B) In a double blind, crossover study, the addition of omeprazole in patients taking diazepam resulted in a 25% to 50% reduction in diazepam clearance. This interaction occurred in about 40% of patients who were fast metabolizers of omeprazole. In slow metabolizers, this interaction was of little significance .

C) Concomitant administration of diazepam and omeprazole resulted in a 130% increase in mean elimination half-life of diazepam and subsequent increases in plasma diazepam concentrations .

D) Diazepam is metabolized by the cytochrome P450 enzyme system. Omeprazole was reported to inhibit individual enzymes in the P450 system in studies of combined omeprazole and diazepam in vitro and in vivo both in animals and humans .

E) Human liver microsomes were used to study the metabolism of diazepam to its two major metabolites nordiazepam (NDZ) and 3-hydroxydiazepam (3-HDZ). In addition, inhibition of these two pathways by omeprazole and omeprazole sulphone was studied. Omeprazole sulphone inhibited both pathways comparably; however, NDZ pathway was less susceptible to omeprazole inhibition .

Omeprazole Overview

• Prescription omeprazole is used alone or with other medications to treat the symptoms of gastroesophageal reflux disease (GERD), a condition in which backward flow of acid from the stomach causes heartburn and possible injury of the esophagus (the tube between the throat and stomach) in adults and children 1 year of age and older. Prescription omeprazole is used to treat damage from GERD in adults and children 1 month of age and older. Prescription omeprazole is used to allow the esophagus to heal and prevent further damage to the esophagus in adults and children 1 year of age and older with GERD. Prescription omeprazole is also used to treat conditions in which the stomach produces too much acid such as Zollinger-Ellison syndrome in adults. Prescription omeprazole is also used to treat ulcers (sores in the lining of the stomach or intestine) and it is also used with other medications to treat and prevent the return of ulcers caused by a certain type of bacteria (H. pylori) in adults. Nonprescription (over-the-counter) omeprazole is used to treat frequent heartburn (heartburn that occurs at least 2 or more days a week) in adults. Omeprazole is in a class of medications called proton-pump inhibitors. It works by decreasing the amount of acid made in the stomach.

Diazepam Overview

• Diazepam is used to relieve anxiety and to control agitation caused by alcohol withdrawal. It is also used along with other medications to control muscle spasms and spasticity caused by certain neurological disorders such as cerebral palsy (condition that causes difficulty with movement and balance), paraplegia (inability to move parts of the body), athetosis (abnormal muscle contractions), and stiff-man syndrome (a rare disorder with muscle rigidity and stiffness). Diazepam is also used along with other medications to control seizures. Diazepam is in a class of medications called benzodiazepines. It works by calming abnormal overactivity in the brain.

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Definitions

Severity Categories

Contraindicated

These drugs, generally, should not be used together simultaneously due to the high risk of severe adverse effects. Combining these medications can lead to dangerous health outcomes and should be strictly avoided unless otherwise instructed by your provider.

Major

This interaction could result in very serious and potentially life-threatening consequences. If you are taking this drug combination, it is very important to be under close medical supervision to minimize severe side effects and ensure your safety. It may be necessary to change a medication or dosage to prevent harm.

Moderate

This interaction has the potential to worsen your medical condition or alter the effectiveness of your treatment. It's important that you are monitored closely and you potentially may need to make adjustments in your treatment plan or drug dosage to maintain optimal health.

Minor

While this interaction is unlikely to cause significant problems, it could intensify side effects or reduce the effectiveness of one or both medications. Monitoring for changes in symptoms and your condition is recommended, and adjustments may be made if needed to manage any increased or more pronounced side effects.

Onset

Rapid: Onset of drug interaction typically occurs within 24 hours of co-administration.

Delayed: Onset of drug interaction typically occurs more than 24 hours after co-administration.

Evidence

Level of documentation of the interaction.

Established: The interaction is documented and substantiated in peer-reviewed medical literature.

Theoretical: This interaction is not fully supported by current medical evidence or well-documented sources, but it is based on known drug mechanisms, drug effects, and other relevant information.

How To Manage The Interaction

Provides a detailed discussion on how patients and clinicians can approach the identified drug interaction as well as offers guidance on what to expect and strategies to potentially mitigate the effects of the interaction. This may include recommendations on adjusting medication dosages, altering the timing of drug administration, or closely monitoring for specific symptoms.

It's important to note that all medical situations are unique, and management approaches should be tailored to individual circumstances. Patients should always consult their healthcare provider for personalized advice and guidance on managing drug interactions effectively.

Mechanism Of Interaction

The theorized or clinically determined reason (i.e., mechanism) why the drug-drug interaction occurs.

Disclaimer: The information provided on this page is for informational purposes only and should not be considered medical advice. Always consult with a qualified healthcare professional regarding your specific circumstances and medical conditions.

Where Does Our Information Come From?

Information for our drug interactions is compiled from several drug compendia, including:

• Gold Standard Drug Database
• Micromedex
• Lexicomp
• DrugBank

The prescribing information for each drug, as published on DailyMED, is also used. 

Individual drug-drug interaction detail pages contain references specific to that interaction. You can click on the reference number within brackets '[]' to see what reference was utilized.

The information posted is fact-checked by HelloPharmacist clinicians and reviewed quarterly.