Drug interactions
Fentanyl intranasal + Isoniazid
Severity: Moderate
Fentanyl intranasal and Isoniazid: 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
Isoniazid may inhibit CYP3A4 and reduce fentanyl clearance, which can enhance and prolong opioid effects. This can cause excessive sedation and respiratory depression.
What this interaction means in plain words
Fentanyl intranasal and Isoniazid 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
Isoniazid inhibits CYP3A4, the main metabolic pathway of fentanyl.
What to do
Monitor sedation and respiratory rate, and lower the fentanyl dose if necessary until effects are stable.
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
Frequently asked questions
Can I take Fentanyl intranasal with Isoniazid?
MediHelp rates the interaction as moderate. Fentanyl intranasal and Isoniazid 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 may inhibit CYP3A4 and reduce fentanyl clearance, which can enhance and prolong opioid effects. This can cause excessive sedation and respiratory depression.
How serious is the interaction between Fentanyl intranasal and Isoniazid?
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 and respiratory rate, and lower the fentanyl dose if necessary until effects are stable.
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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