Autonomics: alpha blockers

Question 1

Phenoxybenzamine

Answer 1

nonselective α-blocker

clinical use: Irreversible. Pheochromocytoma (used

preoperatively) to prevent catecholamine
(hypertensive) crisis

Adverse effects: Orthostatic hypotension, reflex tachycardia

Question 2

Phentolamine

Answer 2

nonselective α-blocker

Clinical use: Reversible. Given to patients on MAO inhibitors
who eat tyramine-containing foods and for
severe cocaine-induced hypertension (2nd line)

Adverse effects: Orthostatic hypotension, reflex tachycardia

Question 3

Prazosin, terazosin,
doxazosin,
tamsulosin

Answer 3

selective α1-blocker

Clinical use: Urinary symptoms of BPH; PTSD (prazosin);
hypertension (except tamsulosin)

Adverse effects: 1st-dose orthostatic hypotension, dizziness,
headache

Question 4

Mirtazapine

Answer 4

selective α2-blocker

Clinical use: Depression

Adverse effects: Sedation, ↑ serum cholesterol, ↑ appetite