Drug interactions
Oxazepam + Phenobarbital
Severity: Major
Oxazepam and Phenobarbital: major interaction.
Last updated
For healthcare professionals — reference only. This page is a brief summary, not medical advice and not a substitute for official labeling or clinical judgement. Always verify before prescribing or dispensing.
Summary
Phenobarbital and oxazepam both depress the CNS, so combined use can cause marked sedation and respiratory depression. Phenobarbital is also an enzyme inducer, though oxazepam is cleared by glucuronidation and is less affected.
What this interaction means in plain words
Oxazepam and Phenobarbital can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for.
Why it happens
Additive GABA-A mediated CNS depression.
What to do
Monitor sedation and respiratory status and use the lowest effective doses. Avoid adding other CNS depressants such as alcohol or opioids.
What to ask your pharmacist
- Does the benefit of taking both outweigh the risk in my case?
- Do I need any blood test, ECG or other check while on both?
- What early warning signs should I watch for, and what should I do if they appear?
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Other interactions of Oxazepam
- Calcium / magnesium / potassium / sodium oxybates + Oxazepam Contraindicated
- Oxazepam + Sodium oxybate Contraindicated
- Alfentanil + Oxazepam Major
- Amobarbital + Oxazepam Major
- Baclofen + Oxazepam Major
- Belladonna and opium + Oxazepam Major
Frequently asked questions
Can I take Oxazepam with Phenobarbital?
MediHelp rates the interaction as major. Oxazepam and Phenobarbital can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for. Phenobarbital and oxazepam both depress the CNS, so combined use can cause marked sedation and respiratory depression. Phenobarbital is also an enzyme inducer, though oxazepam is cleared by glucuronidation and is less affected.
How serious is the interaction between Oxazepam and Phenobarbital?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor sedation and respiratory status and use the lowest effective doses. Avoid adding other CNS depressants such as alcohol or opioids.
What other medicines interact with Oxazepam?
MediHelp also lists interactions of Oxazepam with, for example, Calcium / magnesium / potassium / sodium oxybates, Sodium oxybate, Alfentanil. The full list is on the Oxazepam page.
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