Drug interactions
Foscarnet + Tobramycin
Severity: Major
Foscarnet and Tobramycin: major interaction.
Last updated Sources: US FDA label
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
Both drugs are nephrotoxic, and combining them raises the risk of acute kidney injury. Reduced renal function in turn increases tobramycin accumulation and ototoxicity risk.
What this interaction means in plain words
Foscarnet and Tobramycin can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for.
Foscarnet belongs to Anti Virals; Tobramycin belongs to Anti Bacterial.
Why it happens
Additive nephrotoxicity affecting renal tubular cells, with secondary aminoglycoside accumulation.
What to do
Avoid the combination where alternatives exist; otherwise hydrate, monitor creatinine and electrolytes frequently, and measure tobramycin levels.
What to ask your pharmacist
- Does the benefit of taking both outweigh the risk in my case?
- Do I need any blood test, ECG or other check while on both?
- What early warning signs should I watch for, and what should I do if they appear?
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References
Other interactions of Tobramycin
- Cidofovir + Tobramycin Contraindicated
- Adefovir + Tobramycin Major
- Amikacin + Tobramycin Major
- Amphotericin b deoxycholate + Tobramycin Major
- Amphotericin b + Tobramycin Major
- Atracurium + Tobramycin Major
Other interactions of Foscarnet
- Cidofovir + Foscarnet Contraindicated
- Foscarnet + Pimozide Contraindicated
- Foscarnet + Thioridazine Contraindicated
- Foscarnet + Vandetanib Contraindicated
- Adagrasib + Foscarnet Major
- Adefovir + Foscarnet Major
Frequently asked questions
Can I take Foscarnet with Tobramycin?
MediHelp rates the interaction as major. Foscarnet and Tobramycin can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for. Both drugs are nephrotoxic, and combining them raises the risk of acute kidney injury. Reduced renal function in turn increases tobramycin accumulation and ototoxicity risk.
How serious is the interaction between Foscarnet and Tobramycin?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid the combination where alternatives exist; otherwise hydrate, monitor creatinine and electrolytes frequently, and measure tobramycin levels.
What other medicines interact with Tobramycin?
MediHelp also lists interactions of Tobramycin with, for example, Cidofovir, Adefovir, Amikacin. The full list is on the Tobramycin page.
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