Drug interactions
Dosulepin + Perphenazine
Severity: Major
Dosulepin and Perphenazine: 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
Both drugs can prolong the QT interval and have anticholinergic and sedative effects. Combined use raises the risk of arrhythmia, and perphenazine may also raise tricyclic levels by inhibiting CYP2D6. Anticholinergic effects and sedation are additive.
What this interaction means in plain words
Dosulepin 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.
Dosulepin belongs to Central Nervous System; Perphenazine belongs to Central Nervous System.
Why it happens
Additive QT prolongation and anticholinergic effects, with CYP2D6 inhibition by perphenazine raising tricyclic concentrations.
What to do
Avoid if possible. If used together, obtain an ECG, correct electrolytes, use lower doses and monitor for anticholinergic toxicity and arrhythmia.
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 Perphenazine
- Ibutilide + Perphenazine Contraindicated
- Perphenazine + Pimozide Contraindicated
- Perphenazine + Thioridazine Contraindicated
- Adagrasib + Perphenazine Major
- Alfentanil + Perphenazine Major
- Amiodarone + Perphenazine Major
Other interactions of Dosulepin
- Dosulepin + Isocarboxazid Contraindicated
- Dosulepin + Phenelzine Contraindicated
- Dosulepin + Thioridazine Contraindicated
- Dosulepin + Tranylcypromine Contraindicated
- Amitriptyline + Dosulepin Major
- Buprenorphine + Dosulepin Major
Frequently asked questions
Can I take Dosulepin with Perphenazine?
MediHelp rates the interaction as major. Dosulepin 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. Both drugs can prolong the QT interval and have anticholinergic and sedative effects. Combined use raises the risk of arrhythmia, and perphenazine may also raise tricyclic levels by inhibiting CYP2D6. Anticholinergic effects and sedation are additive.
How serious is the interaction between Dosulepin 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: Avoid if possible. If used together, obtain an ECG, correct electrolytes, use lower doses and monitor for anticholinergic toxicity and arrhythmia.
What other medicines interact with Perphenazine?
MediHelp also lists interactions of Perphenazine with, for example, Ibutilide, Pimozide, Thioridazine. The full list is on the Perphenazine page.
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