Epinephrine and Phenoxybenzamine interaction
Epinephrine and Phenoxybenzamine: both prescribing labels describe an interaction that usually calls for monitoring, a dose change, or spacing the doses.
Usually manageable with monitoring or a dose change. Tell your pharmacist you take both.
What the FDA labels say
From the Epinephrine label · effective 2026-07-06
Epinephrine may antagonize the neuronal blockade produced by guanethidine resulting in decreased antihypertensive effect and requiring increased dosage of the latter.
Drugs antagonizing pressor effects of epinephrine α-blockers, such as phentolamine Vasodilators, such as nitrates Diuretics Antihypertensives Ergot alkaloids Drugs potentiating pressor effects of epinephrine • Sympathomimetics • β-blockers, such as propranolol • Tricyclic anti-depressants • Monoamine oxidase (MAO) inhibitors • Catechol-O-methyl transferase (COMT)…
• Drugs that counter the pressor effects of epinephrine include alpha blockers, vasodilators such as nitrates, diuretics, antihypertensives, and ergot alkaloids.
From the Phenoxybenzamine (Phenoxybenzamine hydrochloride) label · effective 2026-07-03
Drug Interactions 2 – Phenoxybenzamine hydrochloride may interact with compounds that stimulate both alpha- and beta- adrenergic receptors (i.e. epinephrine) to produce an exaggerated hypotensive response and tachycardia (see WARNING ).
Taking more than these two? Interactions stack. Check your whole list at once; it stays in your browser.
Open in the checkerNot medical advice. Interaction Checker quotes FDA label text and NIH fact sheets. Whether an interaction matters for you depends on doses, timing, kidney and liver function, and other conditions. Confirm with a pharmacist or prescriber.