Drug interactions
doxazosin + methyldopa
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 BP-lowering with risk of marked orthostatic hypotension and syncope, particularly with the first dose or rapid titration of doxazosin.
Mechanism of action
Pharmacodynamic synergy: central alpha-2 agonism plus peripheral alpha-1 blockade → decreased sympathetic tone and vasodilation.
Clinical management
Avoid rapid titration. Initiate doxazosin 1 mg at bedtime and uptitrate slowly; monitor orthostatic BP after the first dose and dose increases.
Drug reference
References
- Aldomet (methyldopa) Prescribing Information — FDA Label
- Cardura (doxazosin) Prescribing Information — FDA Label
- Doxazosin: Drug Interactions — Lexicomp
Frequently asked questions
Can I take doxazosin with methyldopa?
The interaction is rated: Moderate. Additive BP-lowering with risk of marked orthostatic hypotension and syncope, particularly with the first dose or rapid titration of doxazosin.
How serious is the interaction between doxazosin and methyldopa?
The interaction is rated: Moderate. Evidence level: High.
How is the interaction between doxazosin and methyldopa managed?
Avoid rapid titration. Initiate doxazosin 1 mg at bedtime and uptitrate slowly; monitor orthostatic BP after the first dose and dose increases.
Why do doxazosin and methyldopa interact?
Pharmacodynamic synergy: central alpha-2 agonism plus peripheral alpha-1 blockade → decreased sympathetic tone and vasodilation.
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