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Drug interactions

Disopyramide + Ritonavir

Severity: Major

Disopyramide and Ritonavir: 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

Ritonavir may raise disopyramide concentrations, increasing the risk of arrhythmias including QT prolongation and anticholinergic toxicity.

What this interaction means in plain words

Disopyramide and Ritonavir 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.

Disopyramide belongs to Cardiovascular; Ritonavir belongs to Anti Virals.

Evidence level: Moderate

Why it happens

Ritonavir inhibits CYP3A4, which is a main route of disopyramide metabolism.

What to do

Avoid if possible; otherwise reduce the disopyramide dose and monitor ECG and serum concentrations.

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?

Bring a full list of your medicines, including over-the-counter products, supplements and herbal remedies, to every pharmacy visit.

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References

Frequently asked questions

Can I take Disopyramide with Ritonavir?

MediHelp rates the interaction as major. Disopyramide and Ritonavir 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. Ritonavir may raise disopyramide concentrations, increasing the risk of arrhythmias including QT prolongation and anticholinergic toxicity.

How serious is the interaction between Disopyramide and Ritonavir?

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 if possible; otherwise reduce the disopyramide dose and monitor ECG and serum concentrations.

What other medicines interact with Ritonavir?

MediHelp also lists interactions of Ritonavir with, for example, Alfuzosin, Amiodarone, Avanafil. The full list is on the Ritonavir page.

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