Drug interactions
doxazosin + verapamil
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.
Overview
Additive antihypertensive effects with increased risk of orthostatic hypotension and dizziness; possible increase in doxazosin exposure with CYP3A4 inhibition by verapamil.
Mechanism of action
Pharmacodynamic additive vasodilation; potential pharmacokinetic effect via CYP3A4 inhibition increasing doxazosin levels.
Clinical management
Start doxazosin at low dose and titrate cautiously; monitor BP and symptoms of orthostasis; consider enhanced monitoring if other CYP3A4 inhibitors are present.
Drug reference
References
- Cardura (doxazosin) Prescribing Information — Interactions and Warnings — FDA Label
- Doxazosin (Cardura) — Summary of Product Characteristics: Interactions with CYP3A4 inhibitors — EMA
- Verapamil: Drug Interactions — Lexicomp
Frequently asked questions
Can I take doxazosin with verapamil?
The interaction is rated: Moderate. Additive antihypertensive effects with increased risk of orthostatic hypotension and dizziness; possible increase in doxazosin exposure with CYP3A4 inhibition by verapamil.
How serious is the interaction between doxazosin and verapamil?
The interaction is rated: Moderate. Evidence level: Moderate.
How is the interaction between doxazosin and verapamil managed?
Start doxazosin at low dose and titrate cautiously; monitor BP and symptoms of orthostasis; consider enhanced monitoring if other CYP3A4 inhibitors are present.
Why do doxazosin and verapamil interact?
Pharmacodynamic additive vasodilation; potential pharmacokinetic effect via CYP3A4 inhibition increasing doxazosin levels.
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