Drug interactions
Foscarnet + Hydroxychloroquine
Severity: Major
Foscarnet and Hydroxychloroquine: 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
Hydroxychloroquine and foscarnet can each prolong the QT interval, and together they increase the chance of serious ventricular arrhythmia. Foscarnet also causes electrolyte shifts such as low calcium, magnesium and potassium, which further raise the risk.
What this interaction means in plain words
Foscarnet and Hydroxychloroquine 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; Hydroxychloroquine belongs to Musculoskeletal.
Why it happens
Additive QT prolongation, with foscarnet-induced electrolyte disturbances (hypocalcemia, hypomagnesemia, hypokalemia) adding to repolarization vulnerability.
What to do
Avoid concurrent use if possible; otherwise monitor ECG and serum calcium, magnesium and potassium closely and correct abnormalities promptly.
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 Hydroxychloroquine
- Arsenic trioxide + Hydroxychloroquine Contraindicated
- Cisapride + Hydroxychloroquine Contraindicated
- Dronedarone + Hydroxychloroquine Contraindicated
- Hydroxychloroquine + Pimozide Contraindicated
- Hydroxychloroquine + Thioridazine Contraindicated
- Hydroxychloroquine + Vandetanib Contraindicated
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 Hydroxychloroquine?
MediHelp rates the interaction as major. Foscarnet and Hydroxychloroquine 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. Hydroxychloroquine and foscarnet can each prolong the QT interval, and together they increase the chance of serious ventricular arrhythmia. Foscarnet also causes electrolyte shifts such as low calcium, magnesium and potassium, which further raise the risk.
How serious is the interaction between Foscarnet and Hydroxychloroquine?
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 concurrent use if possible; otherwise monitor ECG and serum calcium, magnesium and potassium closely and correct abnormalities promptly.
What other medicines interact with Hydroxychloroquine?
MediHelp also lists interactions of Hydroxychloroquine with, for example, Arsenic trioxide, Cisapride, Dronedarone. The full list is on the Hydroxychloroquine page.
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