Drug interactions
Fosphenytoin + Gentamicin
Severity: Minor
Fosphenytoin and Gentamicin: 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
Any effect of fosphenytoin on gentamicin through P-glycoprotein is theoretical, and gentamicin is eliminated mainly by glomerular filtration rather than efflux transport. No clinically meaningful change in gentamicin levels has been established.
What this interaction means in plain words
Fosphenytoin and Gentamicin have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised.
Fosphenytoin belongs to Central Nervous System; Gentamicin belongs to Anti Bacterial.
Why it happens
Theoretical P-glycoprotein induction by phenytoin; not established as clinically relevant for gentamicin.
What to do
No adjustment is needed. Continue routine gentamicin level and renal function monitoring.
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 Gentamicin
- Cidofovir + Gentamicin Contraindicated
- Adefovir + Gentamicin Major
- Amikacin + Gentamicin Major
- Amlodipine-hydrochlorothiazide-valsartan + Gentamicin Major
- Amphotericin b deoxycholate + Gentamicin Major
- Amphotericin b + Gentamicin Major
Other interactions of Fosphenytoin
- Dronedarone + Fosphenytoin Contraindicated
- Fosphenytoin + Ledipasvir-sofosbuvir Contraindicated
- Fosphenytoin + Lorlatinib Contraindicated
- Fosphenytoin + Lurasidone Contraindicated
- Fosphenytoin + Ranolazine Contraindicated
- Fosphenytoin + Sofosbuvir-velpatasvir-voxilaprevir Contraindicated
Frequently asked questions
Can I take Fosphenytoin with Gentamicin?
MediHelp rates the interaction as minor. Fosphenytoin and Gentamicin have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised. Any effect of fosphenytoin on gentamicin through P-glycoprotein is theoretical, and gentamicin is eliminated mainly by glomerular filtration rather than efflux transport. No clinically meaningful change in gentamicin levels has been established.
How serious is the interaction between Fosphenytoin and Gentamicin?
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 adjustment is needed. Continue routine gentamicin level and renal function monitoring.
What other medicines interact with Gentamicin?
MediHelp also lists interactions of Gentamicin with, for example, Cidofovir, Adefovir, Amikacin. The full list is on the Gentamicin page.
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