Drug interactions
Diphenhydramine + Tamsulosin
Severity: Minor
Diphenhydramine and Tamsulosin: minor 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
Diphenhydramine inhibits CYP2D6 and could modestly raise tamsulosin exposure. Sedation and dizziness from diphenhydramine may add to alpha-blocker effects, especially in older adults.
What this interaction means in plain words
Diphenhydramine and Tamsulosin have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised.
Diphenhydramine belongs to Respiratory; Tamsulosin belongs to Genitourinary.
Why it happens
Weak CYP2D6 inhibition by diphenhydramine and additive dizziness effects.
What to do
Counsel the patient about dizziness and fall risk, and avoid regular diphenhydramine in older patients where possible.
What to ask your pharmacist
- Is there anything I should notice while taking both?
- Do I need to tell my doctor at the next visit?
Pro+ members
Unlock the full page
Create an account and start a Pro+ trial to unlock the full management advice for Diphenhydramine and Tamsulosin, 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 7 days on the web. No card needed.
Other interactions of Tamsulosin
- Alfuzosin + Tamsulosin Major
- Avanafil + Tamsulosin Major
- Ceritinib + Tamsulosin Major
- Clarithromycin + Tamsulosin Major
- Cobicistat + Tamsulosin Major
- Doxazosin + Tamsulosin Major
Other interactions of Diphenhydramine
Frequently asked questions
Can I take Diphenhydramine with Tamsulosin?
MediHelp rates the interaction as minor. Diphenhydramine and Tamsulosin have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised. Diphenhydramine inhibits CYP2D6 and could modestly raise tamsulosin exposure. Sedation and dizziness from diphenhydramine may add to alpha-blocker effects, especially in older adults.
How serious is the interaction between Diphenhydramine and Tamsulosin?
MediHelp rates it minor, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Counsel the patient about dizziness and fall risk, and avoid regular diphenhydramine in older patients where possible.
What other medicines interact with Tamsulosin?
MediHelp also lists interactions of Tamsulosin with, for example, Alfuzosin, Avanafil, Ceritinib. The full list is on the Tamsulosin 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.
