Hypersensitivity to doxazosin or other quinazolines

Use with caution in liver disease or recent cerebrovascular accident (CVA)
Rule out prostate cancer before initiating therapy
May cause first-dose syncope or sudden loss of consciousness
Risk of orthostatic hypotension (dose dependent)
Potential for hypotension, dry mouth, and urinary complications in elderly
Priapism (painful penile erection, sustained for hours and unrelieved by sexual intercourse or masturbation) rarely reported (probably less frequently than once in every several thousand patients), with alpha-1 antagonists, including doxazosin; because condition can lead to permanent impotence if not promptly treated, patients must be advised about seriousness of condition
Concomitant use of other antihypertensives (additive hypotensive effects)
Extended-release form not indicated for hypertension
Concomitant administration of immediate-release form with a phosphodiesterase-5 (PDE-5) inhibitor can result in additive blood pressure lowering effects and symptomatic hypotension
May increase the risk of heart failure by exacerbating underlying myocardial dysfunction by β1Receptor stimulation with increases in renin and aldosterone
May cause CNS depression, which may impair ability to operate heavy machinery and performing tasks that require mental alertness
Allergic reactions, including urticaria, rash, angioedema, pruritus, and respiratory symptoms may occur
Intraoperative floppy iris syndrome reported in cataract surgery patients who received alph1-blocker therapy; discontinuing alpha-blocker therapy prior to surgery does not appear to be of benefit
Decreases in white blood cells (WBC) and neutrophil count reported; WBC and neutrophil counts returned to normal following discontinuation of therapy