Drug interactions
Moxifloxacin + Saquinavir
Severity: Major
Moxifloxacin and Saquinavir: major interaction.
Last updated Sources: UK SmPC
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 prolong the QT interval, and ritonavir-boosted saquinavir has a labeled QT/PR warning. Together they raise the risk of torsades de pointes and other serious arrhythmias.
What this interaction means in plain words
Moxifloxacin and Saquinavir 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.
Why it happens
Additive prolongation of ventricular repolarization through potassium channel effects.
What to do
Avoid the combination and choose another antibiotic. If it cannot be avoided, obtain an ECG before and during treatment and correct potassium and magnesium.
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 Moxifloxacin
- Amiodarone + Moxifloxacin Contraindicated
- Arsenic trioxide + Moxifloxacin Contraindicated
- Disopyramide + Moxifloxacin Contraindicated
- Dofetilide + Moxifloxacin Contraindicated
- Dronedarone + Moxifloxacin Contraindicated
- Droperidol + Moxifloxacin Contraindicated
Frequently asked questions
Can I take Moxifloxacin with Saquinavir?
MediHelp rates the interaction as major. Moxifloxacin and Saquinavir 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 prolong the QT interval, and ritonavir-boosted saquinavir has a labeled QT/PR warning. Together they raise the risk of torsades de pointes and other serious arrhythmias.
How serious is the interaction between Moxifloxacin and Saquinavir?
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 and choose another antibiotic. If it cannot be avoided, obtain an ECG before and during treatment and correct potassium and magnesium.
What other medicines interact with Moxifloxacin?
MediHelp also lists interactions of Moxifloxacin with, for example, Amiodarone, Arsenic trioxide, Disopyramide. The full list is on the Moxifloxacin page.
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