Tobramycin and Cidofovir Interaction
Drug interaction information between Tobramycin and Cidofovir.
Tobramycin and Cidofovir have a documented major interaction in FDA labeling.
FDA drug labeling documents a major-severity interaction between Tobramycin and Cidofovir. Major interactions are generally avoided, moderate ones may need monitoring or a dose adjustment, and minor ones are usually low-risk. This page shows the documented mechanism and guidance. Label-documented interactions are not a complete safety review, so always confirm your own medications with a pharmacist or doctor. Educational information, not medical advice.
How They Interact
Both drugs have the potential to damage your kidneys. Taking them together adds to this risk and can lead to kidney failure.
What To Do
Do not use these drugs at the same time. Your doctor must choose a different therapy.
FDA Label Information
Nephrotoxic agents Concomitant administration of cidofovir injection and agents with nephrotoxic potential [e.g., intravenous aminoglycosides (e.g., tobramycin, gentamicin, and amikacin), amphotericin B, foscarnet, intravenous pentamidine, vancomycin, and nonsteroidal anti-inflammatory agents] is contraindicated.
Cidofovir Also Interacts With
- Vancomycin major
- Gentamicin major
- Amikacin major
- Amphotericin B major
- Furosemide minor
Frequently Asked Questions
Can I take Tobramycin and Cidofovir together?
This is a major interaction. Do not use these drugs at the same time. Your doctor must choose a different therapy.
How serious is the interaction between Tobramycin and Cidofovir?
This interaction is classified as "major" severity by the FDA. Major interactions may be life-threatening or cause serious side effects.
Why do Tobramycin and Cidofovir interact?
Both drugs have the potential to damage your kidneys. Taking them together adds to this risk and can lead to kidney failure.
Understanding the Tobramycin and Cidofovir Interaction
FDA-approved prescribing information for these two drugs flags their combination as a major-severity interaction. Tobramycin belongs to the Aminoglycoside Antibiotic class and Cidofovir belongs to the Antiviral (Nucleotide Analog) class - two categories that can collide when co-prescribed. The mechanism described in FDA labeling is: Both drugs have the potential to damage your kidneys. Severity tiers matter: major flags generally advise avoidance, moderate flags often require monitoring or dose adjustment, and minor flags may only call for awareness.
Context around a specific patient determines real-world impact. Tobramycin has 2 total documented interactions on file in this dataset, and Cidofovir has 16. Each additional medication compounds the interaction surface, which is why pharmacists run full-profile checks rather than evaluating one pair at a time. FDA-derived guidance for this pair is: Do not use these drugs at the same time. Timing of doses, renal and hepatic function, age, and other concurrent prescriptions all shape whether a labeled interaction matters clinically.
An interaction flag is not a verdict. A large share of labeled interactions are managed routinely in clinical practice, the fix may be as simple as spacing doses or adding a monitoring test. Others require the prescriber to choose a different medication entirely. This page surfaces FDA-sourced labeling and openFDA data for educational purposes only; it is not medical advice and cannot account for your full clinical picture. Never start, stop, or adjust either Tobramycin or Cidofovir based on a web page, speak with your prescriber or pharmacist before making any change.
Sources: FDA Drug Labels (SPL) via openFDA (2026). This is for informational purposes only and is not medical advice. Always consult your healthcare provider about drug interactions.
Read our methodology - how this data is sourced, computed, and verified.