Drug interactions
Fentanyl intranasal + Metronidazole
Severity: Minor
Fentanyl intranasal and Metronidazole: minor 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
Fentanyl is cleared mainly by CYP3A4, and inhibitors can raise levels and cause respiratory depression. Metronidazole is a weak inhibitor at most, so a clinically important effect is unlikely but cannot be fully excluded.
What this interaction means in plain words
Fentanyl intranasal and Metronidazole have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised.
Why it happens
Possible weak CYP3A4 inhibition by metronidazole reducing fentanyl clearance.
What to do
No dose change is routinely needed; monitor for sedation and respiratory depression, especially at initiation.
What to ask your pharmacist
- Is there anything I should notice while taking both?
- Do I need to tell my doctor at the next visit?
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Other interactions of Metronidazole
- Ethanol + Metronidazole Contraindicated
- Metronidazole + Pimozide Contraindicated
- Amiodarone + Metronidazole Major
- Disulfiram + Metronidazole Major
- Ergotamine + Metronidazole Major
- Lomitapide + Metronidazole Major
Frequently asked questions
Can I take Fentanyl intranasal with Metronidazole?
MediHelp rates the interaction as minor. Fentanyl intranasal and Metronidazole have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised. Fentanyl is cleared mainly by CYP3A4, and inhibitors can raise levels and cause respiratory depression. Metronidazole is a weak inhibitor at most, so a clinically important effect is unlikely but cannot be fully excluded.
How serious is the interaction between Fentanyl intranasal and Metronidazole?
MediHelp rates it minor, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: No dose change is routinely needed; monitor for sedation and respiratory depression, especially at initiation.
What other medicines interact with Metronidazole?
MediHelp also lists interactions of Metronidazole with, for example, Ethanol, Pimozide, Amiodarone. The full list is on the Metronidazole page.
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