Disopyramide and Ritonavir: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Ritonavir
Disopyramide
How we grade severity & evidence
Severity levels
- Contraindicated: These should generally not be used together.
- Major: Potentially serious — often needs a change or close monitoring.
- Moderate: Can be significant — usually manageable with monitoring.
- Minor: Usually limited clinical impact.
Evidence grades
- Established: Well documented — supported by controlled studies or strong clinical data.
- Probable: Good supporting evidence, though not definitively proven.
- Suspected: Some evidence suggests this interaction, but it is not well established.
- Possible: Limited or conflicting evidence; the interaction may occur.
- Theoretical: Predicted from the drugs' pharmacology; not yet confirmed in people.
Ratings come from the documented interaction literature and are reviewed by a pharmacist. They describe the documented risk of the combination, not what will necessarily happen to you — your dose, timing, and health picture all matter.
What happens
Increased disopyramide exposure and potential toxicity (anticholinergic effects, hypotension, heart failure, cardiac arrhythmias)
Interaction Deep Dive
Caution is warranted and therapeutic concentration monitoring is recommended for antiarrhythmics such as disopyramide when coadministered with ritonavir1.
Why it happens (mechanism)
Inhibition of CYP3A-mediated metabolism of disopyramide
Literature reports
1 report — tap to read
a) Ritonavir is thought to be metabolized by several cytochrome P450 isoenzymes, with CYP3A prominent among them. The CYP3A enzymes may also be significantly involved in disopyramide metabolism. As a result, ritonavir may competitively inhibit disopyramide metabolism, thereby producing disopyramide toxicity. Cardiac and neurologic events have been reported in patients receiving ritonavir and disopyramide, and the possibility of drug interaction can not be excluded 2.
Common questions
Can I take Disopyramide and Ritonavir together?
Increased disopyramide exposure and potential toxicity (anticholinergic effects, hypotension, heart failure, cardiac arrhythmias) Always confirm with your pharmacist or prescriber before making any change.
How serious is the Disopyramide and Ritonavir interaction?
It is rated major. Potentially serious — often needs a change or close monitoring.
How quickly could this interaction happen?
The documented onset is "delayed". Effects tend to build up gradually over days to weeks.
How strong is the evidence for this interaction?
The evidence is graded "probable". Good supporting evidence, though not definitively proven.
Questions for your pharmacist
- Does my dose of Disopyramide or Ritonavir need adjusting while I take them together?
- What symptoms should prompt me to call you or my prescriber right away?
- Does the timing of my doses matter for this combination?
- Is there a safer alternative to one of these medications for me?
References (2)
- Product Information: NORVIR(R) oral tablets, oral solution, oral powder, ritonavir oral tablets, oral solution, oral powder. AbbVie Inc (per FDA), North Chicago, IL, 2019. DailyMed
- Product Information: NORVIR(R), ritonavir capsules, ritonavir oral solution. Abbott Laboratories, Abbott Park, IL, 2005. DailyMed
Keep reading about Ritonavir
Keep reading about Disopyramide
These medications also interact with supplements
Prescription drugs aren't the whole picture — herbal and dietary supplements can interact with them too. From the evidence-graded Natural Medicines database:
major · moderate · minor — check everything you take with our drug–supplement interaction checker.
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