Drug interactions
Colistin + Foscarnet
Severity: Major
Colistin and Foscarnet: major 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
Colistin and foscarnet are both nephrotoxic, so their combination increases the likelihood of renal impairment. Foscarnet can also cause electrolyte disturbances that may add to risk in a patient with declining kidney function.
What this interaction means in plain words
Colistin and Foscarnet 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.
Colistin belongs to Anti Bacterial; Foscarnet belongs to Anti Virals.
Why it happens
Additive direct nephrotoxicity of both drugs, with foscarnet-related electrolyte disturbances adding to the risk.
What to do
Avoid the combination if alternatives exist. If it is necessary, hydrate adequately, monitor creatinine, calcium, magnesium, potassium and phosphate frequently, and adjust doses to renal function.
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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Other interactions of Colistin
- Colistin + Polymyxin b Contraindicated
- Amikacin + Colistin Major
- Amphotericin b deoxycholate + Colistin Major
- Amphotericin b + Colistin Major
- Atracurium + Colistin Major
- Bacitracin + Colistin 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 Colistin with Foscarnet?
MediHelp rates the interaction as major. Colistin and Foscarnet 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. Colistin and foscarnet are both nephrotoxic, so their combination increases the likelihood of renal impairment. Foscarnet can also cause electrolyte disturbances that may add to risk in a patient with declining kidney function.
How serious is the interaction between Colistin and Foscarnet?
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 if alternatives exist. If it is necessary, hydrate adequately, monitor creatinine, calcium, magnesium, potassium and phosphate frequently, and adjust doses to renal function.
What other medicines interact with Colistin?
MediHelp also lists interactions of Colistin with, for example, Polymyxin b, Amikacin, Amphotericin b deoxycholate. The full list is on the Colistin page.
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