Drug interactions
Perphenazine + Tamoxifen
Severity: Major
Perphenazine and Tamoxifen: major 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
Perphenazine inhibits CYP2D6, the enzyme that converts tamoxifen to its active metabolite endoxifen. Lower endoxifen exposure may reduce the anticancer benefit of tamoxifen.
What this interaction means in plain words
Perphenazine and Tamoxifen 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 belongs to Central Nervous System; Tamoxifen belongs to Endocrine.
Why it happens
CYP2D6 inhibition by perphenazine reduces tamoxifen bioactivation to endoxifen.
What to do
Avoid the combination when feasible and choose an antipsychotic with minimal CYP2D6 inhibition. If it cannot be avoided, discuss with the oncologist about alternative endocrine therapy.
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?
Pro+ members
Unlock the full page
Create an account and start a Pro+ trial to unlock the full management advice for Perphenazine and Tamoxifen, the additional notes, the evidence detail and the whole-prescription interaction checker.
- Full clinical management advice
- Additional notes
- Evidence detail
- Interaction checker for a whole prescription
Try Pro+ free for 14 days on the web. No card needed.
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 Tamoxifen
- Amiodarone + Tamoxifen Major
- Anastrozole + Tamoxifen Major
- Bupropion + Tamoxifen Major
- Carbamazepine + Tamoxifen Major
- Cinacalcet + Tamoxifen Major
- Dacomitinib + Tamoxifen Major
Frequently asked questions
Can I take Perphenazine with Tamoxifen?
MediHelp rates the interaction as major. Perphenazine and Tamoxifen 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, the enzyme that converts tamoxifen to its active metabolite endoxifen. Lower endoxifen exposure may reduce the anticancer benefit of tamoxifen.
How serious is the interaction between Perphenazine and Tamoxifen?
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 when feasible and choose an antipsychotic with minimal CYP2D6 inhibition. If it cannot be avoided, discuss with the oncologist about alternative endocrine therapy.
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.
Full monographs, dosing and an interaction checker in the MediHelp app
Open the complete reference, check multi-drug interactions and use dosing tools in the MediHelp app.
