Irreversible α antagonist (14-18 hours); inhibits reuptake of released norepinephrine; blocks histamine (H₁), acetylcholine, and serotonin receptors; reduces BP when sympathetic tone is high (eg. standing up)

Orthostatic hypotension and tachycardia; nasal stuffiness and inhibition of ejaculation also occur; CNS symptoms – fatigue, sedation, nausea

Pheochromocytoma (tumor of the adrenal medulla or sympathetic ganglion cells that secretes catecholamines – symptoms include hypertension, headaches, palpitations, and increased sweating); occasionally Raynaud’s

Reversible; reduces peripheral resistance through blockade of α₁ receptors and stimulates heart by antagonism of α₂ receptors (↑ release of NE from sympathetic nerves)

Related to cardiac stimulation – severe tachycardia, arrhythmias, myocardial ischemia

Pheochromocytoma

Reversible; highly selective for α₁ receptors; relaxes smooth muscle in vessels and prostate (half-life 3 hours)

Relative absence of tachycardia, orthostatic hypotension may be severe after first few doses, dizziness

first dose effect

Hypertension, occasionally Raynaud’s phenomenon and other conditions involving excessive reversible vasospasm, BPH  

Reversible α₁ antagonist (half-life 9-12 hours)

Orthostatic hypotension

first dose effect

Hypertension, benign prostatic hyperplasia (BPH)

Reversible α1 antagonist (half-life 9-12 hours)

Orthostatic hypotension

first dose effect

Hypertension, benign prostatic hyperplasia (BPH)

Reversible α1 antagonist, higher affinity for α_1A and α_1D than for the α_1B subtype; greater potency in inhibiting contraction in  prostate smooth muscle versus vascular

Less effect on standing BP

first dose effect

BPH

α₂ selective antagonist; promotes NE release through blockade of presynaptic α₂ receptors

Tachycardia, hypertension

Orthostatic hypotension, used for erectile dysfunction (replaced by phosphodiesterase-5 inhibitors)

Block β₁ and β₂ receptors; lowers HR and BP, reduces renin; lipophilic crosses into CNS

Bradycardia, worsened asthma, fatigue, vivid dreams, cold hands

Hypertension, angina pectoris, arrhythmias, migraine, hyperthyroidism

Reversible α antagonist; has both α1 selective and β-antagonistic effects; lowers BP with less limited HR increase

Less tachycardia than other α₁ agents

Hypertension; hypertensive emergencies