Drug interactions
Atomoxetine + Quinidine
Severity: Major
Atomoxetine and Quinidine: 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
Quinidine is a strong CYP2D6 inhibitor and raises atomoxetine exposure substantially, similar to what is seen in CYP2D6 poor metabolizers. Both agents can also affect cardiac repolarization, so QT-related arrhythmia risk and adrenergic effects such as tachycardia and hypertension may increase.
What this interaction means in plain words
Atomoxetine and Quinidine 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.
Atomoxetine belongs to Central Nervous System; Quinidine belongs to Anti Parasitic.
Why it happens
Quinidine inhibits CYP2D6-mediated metabolism of atomoxetine, with additive QT prolongation.
What to do
Avoid the combination where possible. If it is necessary, start atomoxetine at a low dose, titrate slowly, and monitor heart rate, blood pressure and ECG.
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?
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References
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 Atomoxetine
- Atomoxetine + Isocarboxazid Contraindicated
- Atomoxetine + Linezolid Contraindicated
- Atomoxetine + Phenelzine Contraindicated
- Atomoxetine + Procarbazine Contraindicated
- Atomoxetine + Rasagiline Contraindicated
- Atomoxetine + Selegiline Contraindicated
Frequently asked questions
Can I take Atomoxetine with Quinidine?
MediHelp rates the interaction as major. Atomoxetine and Quinidine 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. Quinidine is a strong CYP2D6 inhibitor and raises atomoxetine exposure substantially, similar to what is seen in CYP2D6 poor metabolizers. Both agents can also affect cardiac repolarization, so QT-related arrhythmia risk and adrenergic effects such as tachycardia and hypertension may increase.
How serious is the interaction between Atomoxetine and Quinidine?
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 the combination where possible. If it is necessary, start atomoxetine at a low dose, titrate slowly, and monitor heart rate, blood pressure and ECG.
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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