Drug interactions
Phenytoin + Triazolam
Severity: Moderate
Phenytoin and Triazolam: 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
Phenytoin lowers triazolam concentrations and may reduce its hypnotic effect.
What this interaction means in plain words
Phenytoin and Triazolam 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
Phenytoin induces CYP3A4, increasing triazolam first-pass and systemic metabolism.
What to do
Monitor for loss of hypnotic efficacy and adjust the triazolam dose or choose an alternative hypnotic. Reassess if phenytoin is stopped, as triazolam exposure will rise.
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 Phenytoin
- Artemether / lumefantrine + Phenytoin Contraindicated
- Bictegravir + Phenytoin Contraindicated
- Cabotegravir + Phenytoin Contraindicated
- Doravirine + Phenytoin Contraindicated
- Elbasvir / grazoprevir + Phenytoin Contraindicated
- Elvitegravir / cobicistat / emtricitabine / tenofovir df + Phenytoin Contraindicated
Frequently asked questions
Can I take Phenytoin with Triazolam?
MediHelp rates the interaction as moderate. Phenytoin and Triazolam 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. Phenytoin lowers triazolam concentrations and may reduce its hypnotic effect.
How serious is the interaction between Phenytoin and Triazolam?
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 for loss of hypnotic efficacy and adjust the triazolam dose or choose an alternative hypnotic. Reassess if phenytoin is stopped, as triazolam exposure will rise.
What other medicines interact with Phenytoin?
MediHelp also lists interactions of Phenytoin with, for example, Artemether / lumefantrine, Bictegravir, Cabotegravir. The full list is on the Phenytoin page.
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