Drug interactions
Nelfinavir + Quinidine
Severity: Contraindicated
Nelfinavir and Quinidine: contraindicated 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
Nelfinavir can raise quinidine concentrations, which increases the risk of QT prolongation and torsades de pointes. Quinidine may also raise nelfinavir exposure through effects on P-glycoprotein. The arrhythmia risk is serious, so the pairing is generally avoided.
What this interaction means in plain words
Nelfinavir and Quinidine are not normally used together. Taking them at the same time is expected to cause harm or make one of them unsafe, so a different medicine is usually chosen for one of the two.
Nelfinavir belongs to Anti Virals; Quinidine belongs to Anti Parasitic.
Why it happens
Nelfinavir inhibits CYP3A4-mediated quinidine metabolism, and quinidine may inhibit P-glycoprotein efflux of nelfinavir.
What to do
Avoid the combination and choose an alternative antiarrhythmic or antiretroviral. If it cannot be avoided, monitor ECG and quinidine levels closely.
What to ask your pharmacist
- Is there an alternative to one of these two medicines for me?
- If both are essential, who is monitoring me and how often?
- Which symptoms mean I should stop and seek help straight away?
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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
Other interactions of Nelfinavir
- Alfuzosin + Nelfinavir Contraindicated
- Avanafil + Nelfinavir Contraindicated
- Dronedarone + Nelfinavir Contraindicated
- Eletriptan + Nelfinavir Contraindicated
- Ergotamine + Nelfinavir Contraindicated
- Flibanserin + Nelfinavir Contraindicated
Frequently asked questions
Can I take Nelfinavir with Quinidine?
MediHelp rates the interaction as contraindicated. Nelfinavir and Quinidine are not normally used together. Taking them at the same time is expected to cause harm or make one of them unsafe, so a different medicine is usually chosen for one of the two. Nelfinavir can raise quinidine concentrations, which increases the risk of QT prolongation and torsades de pointes. Quinidine may also raise nelfinavir exposure through effects on P-glycoprotein. The arrhythmia risk is serious, so the pairing is generally avoided.
How serious is the interaction between Nelfinavir and Quinidine?
MediHelp rates it contraindicated, 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 an alternative antiarrhythmic or antiretroviral. If it cannot be avoided, monitor ECG and quinidine levels closely.
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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