|Trade names||Cardura, Carduran, others|
|By mouth (tablets)|
|Elimination half-life||22 hours|
|CompTox Dashboard (EPA)|
|Chemical and physical data|
|Molar mass||451.483 g·mol−1|
|3D model (JSmol)|
Doxazosin, sold under the brand names Cardura among others, is a medication used to treat symptoms of benign prostatic hyperplasia (enlarged prostate) and hypertension (high blood pressure). For high blood pressure, it is a less preferred option. It is taken by mouth.
Common side effects include dizziness, sleepiness, swelling, nausea, shortness of breath, and abdominal pain. Severe side effects may include low blood pressure with standing, an irregular heart beat, and priapism. It is a α1-selective adrenergic blocker in the quinazoline class of compounds.
Doxazosin was patented in 1977 and came into medical use in 1988. It is available as a generic medication. In 2019, it was the 210th most commonly prescribed medication in the United States, with more than 2 million prescriptions.
Doxazosin is usually added to other antihypertensive therapy such as calcium channel antagonists, diuretics, beta-adrenoreceptor antagonists, angiotensin-converting enzyme inhibitors and angiotensin-2 receptor blockers.
Doxazosin is generally considered to be safe, well tolerated and effective as an add-on antihypertensive drug.
Like other alpha-1 receptor antagonists, it has a role in the peri-operative management of pheochromocytoma.
Doxazosin is considered to be effective in reducing urinary symptom scores and improving peak urinary flow in men with benign prostatic hypertrophy.
The Antihypertensive and Lipid Lowering Treatment to Prevent Heart Attack Trial (ALLHAT) study stopped its arm of the trial looking at alpha blockers, because doxazosin was less effective than a simple diuretic, and because patients on doxazosin had a 25% higher rate of cardiovascular disease and twice the rate of congestive heart failure as patients on diuretics. Pfizer, aware of the results before publication, launched a marketing campaign in early 2000, and sales were largely unaffected, despite the dangers highlighted by the study.