Diazepam with Isoniazid Interaction Details
Brand Names Associated with Diazepam
- Diazepam
- Diazepam Intensol®
- Valium®
- Valrelease®
Brand Names Associated with Isoniazid
- Hyzyd®
- INH®
- IsonaRif® (as a combination product containing Isoniazid, Rifampin)
- Isoniazid
- Laniazid®
- Nydrazid®
- Rifamate® (as a combination product containing Isoniazid, Rifampin)
- Rifater® (as a combination product containing Isoniazid, Pyrazinamide, Rifampin)
- Rimifon®
- Stanozide®
- Tubizid®
Medical Content Editor Dr. Brian Staiger, PharmD
Last updated
Nov 19, 2023
Interaction Effect
An increased risk of benzodiazepine toxicity (sedation, respiratory depression)
Interaction Summary
Concomitant diazepam and isoniazid therapy has been reported to result in a prolongation of diazepam's plasma half-life and a reduction in its clearance. The decrease in metabolism of diazepam is thought to be due to the ability of isoniazid to inhibit hepatic microsomal enzymes. Some patients may require a reduction in diazepam dosage with concurrent isoniazid therapy.
Severity
Moderate
Onset
Delayed
Evidence
Probable
How To Manage Interaction
Monitor patients receiving isoniazid and diazepam for signs of benzodiazepine toxicity, including respiratory depression, somnolence, and sedation.
Mechanism Of Interaction
Inhibition of cytochrome P450 3A4-mediated diazepam metabolism
Diazepam Overview
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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.
Isoniazid Overview
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Isoniazid is used with other drugs to treat tuberculosis (TB; a serious infection that affects the lungs and sometimes other parts of the body). Isoniazid is also used with other drugs to treat people with latent (resting or nongrowing) TB including those in close contact with people who have active TB, a positive tuberculin skin test, human immunodeficiency virus (HIV), and those with pulmonary fibrosis (scarring of the lungs with an unknown cause). Isoniazid is in a class of medications called antituberculosis agents. It works by killing the bacteria that cause tuberculosis.
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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:
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.