Drug Interaction Report

Disopyramide and Cobicistat: Interaction Details

AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature

Cobicistat

Tybost
+

Disopyramide

Norpace Norpace® Norpace® CR
Dr. Brian Staiger, PharmD, BCPS
Medically reviewed by
Updated Aug 8, 2026
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Interaction severity
Major
Potentially serious — often needs a change or close monitoring.
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.

Of 284 documented Disopyramide interactions, 247 are rated major — including this one.
Worried about symptoms right now? Contact your pharmacist or prescriber, or call Poison Control at 1-800-222-1222 (US). Call 911 for an emergency.
Onset
unspecified
Evidence
theoretical
Severity
Major

What happens

Increased disopyramide exposure

Interaction Deep Dive

Concurrent use of cobicistat, a CYP3A inhibitor2, with disopyramide, a CYP3A substrate 1, may lead to increased exposure of disopyramide. Although specific interaction studies have not been performed, life-threatening interactions have been reported when disopyramide was administered with clarithromycin or erythromycin, which are known CYP3A inhibitors 1. If concurrent therapy is necessary, measure disopyramide exposure if available 2. Clinical monitoring is recommended upon coadministration with antiarrhythmics, such as disopyramide 3.

Why it happens (mechanism)

Inhibition of CYP3A-mediated metabolism of disopyramide

Common questions

Can I take Disopyramide and Cobicistat together?

Increased disopyramide exposure Always confirm with your pharmacist or prescriber before making any change.

How serious is the Disopyramide and Cobicistat interaction?

It is rated major. Potentially serious — often needs a change or close monitoring.

How quickly could this interaction happen?

The documented onset is "unspecified". The timing of this interaction is not well characterized.

How strong is the evidence for this interaction?

The evidence is graded "theoretical". Predicted from the drugs' pharmacology; not yet confirmed in people.

Questions for your pharmacist

  • Does my dose of Disopyramide or Cobicistat 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 (3)

  1. Product Information: NORPACE(R), NORPACE(R) CR oral capsules, extended-release capsules, disopyramide phosphate oral capsules, extended-release capsules. G.D. Searle LLC, Chicago, IL, 2006. DailyMed
  2. Product Information: STRIBILD(TM) oral tablets, elvitegravir cobicistat emtricitabine tenofovir disoproxil fumarate oral tablets. Gilead Sciences, Inc. (per manufacturer), Foster City, CA, 2012. DailyMed
  3. Product Information: TYBOST(R) oral tablets, cobicistat oral tablets. Gilead Sciences Inc (per FDA), Foster City, CA, 2025. DailyMed
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Beyond drug–drug

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Prescription drugs aren't the whole picture — herbal and dietary supplements can interact with them too. From the evidence-graded Natural Medicines database:

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This information is for education, not a substitute for professional medical advice. Do not start, stop, or change any medication without talking to your pharmacist or prescriber.