Drug interactions
Ciprofloxacin + Foscarnet
Severity: Moderate
Ciprofloxacin and Foscarnet: moderate 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
Both drugs have been associated with seizures, and case reports describe seizures when they were used together. Foscarnet also causes electrolyte disturbances such as hypocalcemia and hypomagnesemia, which may further lower seizure threshold.
What this interaction means in plain words
Ciprofloxacin and Foscarnet can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken.
Ciprofloxacin belongs to Anti Bacterial; Foscarnet belongs to Anti Virals.
Why it happens
Additive pharmacodynamic lowering of seizure threshold (quinolone GABA antagonism plus foscarnet-induced electrolyte changes); not fully established.
What to do
Monitor calcium, magnesium and potassium and watch for neurologic symptoms. Prefer a non-quinolone antibiotic in patients with seizure history.
What to ask your pharmacist
- Should I take them at different times of day?
- Does the dose of either medicine need to change?
- Is there anything I should avoid, such as alcohol or certain foods, while on both?
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Other interactions of Ciprofloxacin
- Agomelatine + Ciprofloxacin Contraindicated
- Ciprofloxacin + Fezolinetant Contraindicated
- Ciprofloxacin + Thioridazine Contraindicated
- Ciprofloxacin + Tizanidine Contraindicated
- Ciprofloxacin + Vandetanib Contraindicated
- Alosetron + Ciprofloxacin 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 Ciprofloxacin with Foscarnet?
MediHelp rates the interaction as moderate. Ciprofloxacin and Foscarnet can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken. Both drugs have been associated with seizures, and case reports describe seizures when they were used together. Foscarnet also causes electrolyte disturbances such as hypocalcemia and hypomagnesemia, which may further lower seizure threshold.
How serious is the interaction between Ciprofloxacin and Foscarnet?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor calcium, magnesium and potassium and watch for neurologic symptoms. Prefer a non-quinolone antibiotic in patients with seizure history.
What other medicines interact with Ciprofloxacin?
MediHelp also lists interactions of Ciprofloxacin with, for example, Agomelatine, Fezolinetant, Thioridazine. The full list is on the Ciprofloxacin page.
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