Drug interactions
Ketamine + Phenobarbital
Severity: Moderate
Ketamine and Phenobarbital: moderate 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 adds to the sedative effect of ketamine and may increase respiratory depression and hypotension. As a CYP3A4 and CYP2B6 inducer, chronic phenobarbital can also speed ketamine clearance and reduce its effect.
What this interaction means in plain words
Ketamine and Phenobarbital can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken.
Why it happens
Additive CNS depression plus hepatic enzyme induction by phenobarbital increasing ketamine metabolism.
What to do
Monitor sedation, ventilation and blood pressure, and titrate ketamine to response, since requirements may differ in chronic phenobarbital users.
What to ask your pharmacist
- Should I take them at different times of day?
- Does the dose of either medicine need to change?
- Is there anything I should avoid, such as alcohol or certain foods, while on both?
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Other interactions of Ketamine
Frequently asked questions
Can I take Ketamine with Phenobarbital?
MediHelp rates the interaction as moderate. Ketamine and Phenobarbital can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken. Phenobarbital adds to the sedative effect of ketamine and may increase respiratory depression and hypotension. As a CYP3A4 and CYP2B6 inducer, chronic phenobarbital can also speed ketamine clearance and reduce its effect.
How serious is the interaction between Ketamine and Phenobarbital?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor sedation, ventilation and blood pressure, and titrate ketamine to response, since requirements may differ in chronic phenobarbital users.
What other medicines interact with Ketamine?
MediHelp also lists interactions of Ketamine with, for example, Benzhydrocodone / acetaminophen, Brexanolone, Buprenorphine buccal. The full list is on the Ketamine page.
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