Drug interactions
Isoniazid + Midazolam
Severity: Moderate
Isoniazid and Midazolam: 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
Midazolam is extensively metabolised by CYP3A4, and inhibitors prolong its sedative effect. Isoniazid has weak to moderate CYP3A4 inhibitory activity, so higher midazolam exposure and prolonged sedation or respiratory depression are possible, especially with repeated or intranasal dosing.
What this interaction means in plain words
Isoniazid and Midazolam 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.
Isoniazid belongs to Anti Bacterial; Midazolam belongs to Central Nervous System.
Why it happens
Isoniazid inhibits CYP3A4, reducing midazolam clearance.
What to do
Use the lowest effective midazolam dose and monitor sedation level and respiratory status for longer than usual. Reduce subsequent doses if oversedation occurs.
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 Isoniazid
Other interactions of Midazolam
- Atazanavir + Midazolam Contraindicated
- Cobicistat + Midazolam Contraindicated
- Darunavir + Midazolam Contraindicated
- Elvitegravir / cobicistat / emtricitabine / tenofovir df + Midazolam Contraindicated
- Fosamprenavir + Midazolam Contraindicated
- Indinavir + Midazolam Contraindicated
Frequently asked questions
Can I take Isoniazid with Midazolam?
MediHelp rates the interaction as moderate. Isoniazid and Midazolam 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. Midazolam is extensively metabolised by CYP3A4, and inhibitors prolong its sedative effect. Isoniazid has weak to moderate CYP3A4 inhibitory activity, so higher midazolam exposure and prolonged sedation or respiratory depression are possible, especially with repeated or intranasal dosing.
How serious is the interaction between Isoniazid and Midazolam?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Use the lowest effective midazolam dose and monitor sedation level and respiratory status for longer than usual. Reduce subsequent doses if oversedation occurs.
What other medicines interact with Isoniazid?
MediHelp also lists interactions of Isoniazid with, for example, Bacillus calmette-guerin substrain tice, Benzhydrocodone / acetaminophen, Carbamazepine. The full list is on the Isoniazid page.
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