Drug interactions
Atomoxetine + Perphenazine
Severity: Major
Atomoxetine and Perphenazine: major interaction.
Last updated Sources: UK SmPC
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
Perphenazine inhibits CYP2D6 and can substantially raise atomoxetine concentrations, increasing adverse effects such as tachycardia, hypertension and insomnia. Both drugs can also prolong the QT interval, adding to arrhythmia risk.
What this interaction means in plain words
Atomoxetine and Perphenazine 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; Perphenazine belongs to Central Nervous System.
Why it happens
CYP2D6 inhibition by perphenazine reduces atomoxetine clearance, combined with additive QT prolongation.
What to do
Start atomoxetine at a reduced dose and titrate slowly, as for CYP2D6 poor metabolizers. Monitor ECG, blood pressure and heart rate.
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 Atomoxetine
- Atomoxetine + Isocarboxazid Contraindicated
- Atomoxetine + Linezolid Contraindicated
- Atomoxetine + Phenelzine Contraindicated
- Atomoxetine + Procarbazine Contraindicated
- Atomoxetine + Rasagiline Contraindicated
- Atomoxetine + Selegiline Contraindicated
Other interactions of Perphenazine
- Ibutilide + Perphenazine Contraindicated
- Perphenazine + Pimozide Contraindicated
- Perphenazine + Thioridazine Contraindicated
- Adagrasib + Perphenazine Major
- Alfentanil + Perphenazine Major
- Amiodarone + Perphenazine Major
Frequently asked questions
Can I take Atomoxetine with Perphenazine?
MediHelp rates the interaction as major. Atomoxetine and Perphenazine 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. Perphenazine inhibits CYP2D6 and can substantially raise atomoxetine concentrations, increasing adverse effects such as tachycardia, hypertension and insomnia. Both drugs can also prolong the QT interval, adding to arrhythmia risk.
How serious is the interaction between Atomoxetine and Perphenazine?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Start atomoxetine at a reduced dose and titrate slowly, as for CYP2D6 poor metabolizers. Monitor ECG, blood pressure and heart rate.
What other medicines interact with Atomoxetine?
MediHelp also lists interactions of Atomoxetine with, for example, Isocarboxazid, Linezolid, Phenelzine. The full list is on the Atomoxetine page.
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