Drug interactions
Marijuana + Quinidine
Severity: Moderate
Marijuana and Quinidine: moderate interaction.
Last updated
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
Cannabinoids such as cannabidiol and THC can inhibit CYP3A4, which could modestly increase quinidine concentrations. Clinical data are sparse, but because quinidine can cause QT prolongation and torsades de pointes, even small increases may matter.
What this interaction means in plain words
Marijuana and Quinidine can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken.
Why it happens
Cannabinoids may inhibit CYP3A4 metabolism of quinidine; the effect is largely predicted from in vitro data.
What to do
Ask patients about cannabis use and monitor ECG for QTc prolongation and signs of cinchonism. Check quinidine levels if use is regular and the dose is being titrated.
What to ask your pharmacist
- Should I take them at different times of day?
- Does the dose of either medicine need to change?
- Is there anything I should avoid, such as alcohol or certain foods, while on both?
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Other interactions of Quinidine
- Adagrasib + Quinidine Contraindicated
- Arsenic trioxide + Quinidine Contraindicated
- Artemether / lumefantrine + Quinidine Contraindicated
- Chloroquine + Quinidine Contraindicated
- Dofetilide + Quinidine Contraindicated
- Dronedarone + Quinidine Contraindicated
Frequently asked questions
Can I take Marijuana with Quinidine?
MediHelp rates the interaction as moderate. Marijuana and Quinidine can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken. Cannabinoids such as cannabidiol and THC can inhibit CYP3A4, which could modestly increase quinidine concentrations. Clinical data are sparse, but because quinidine can cause QT prolongation and torsades de pointes, even small increases may matter.
How serious is the interaction between Marijuana and Quinidine?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Ask patients about cannabis use and monitor ECG for QTc prolongation and signs of cinchonism. Check quinidine levels if use is regular and the dose is being titrated.
What other medicines interact with Quinidine?
MediHelp also lists interactions of Quinidine with, for example, Adagrasib, Arsenic trioxide, Artemether / lumefantrine. The full list is on the Quinidine page.
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