Does taking 8 milligrams of doxazosin (alpha-1 adrenergic blocker) increase the risk of myocardial infarction (heart attack) and cerebrovascular accident (stroke)?

From the Guidelines

Taking 8 mg of doxazosin does not conclusively increase the risk of myocardial infarction or cerebrovascular accident, but its use should be approached with caution due to potential risks of heart failure, as suggested by the ALLHAT study 1. The ALLHAT study, which randomized 42,418 patients to different antihypertensive therapies, including doxazosin, found that the doxazosin arm was stopped prematurely due to a higher risk of heart failure compared to other treatments 1. However, the study did not demonstrate a clear increase in the risk of heart attack or stroke with doxazosin use 1. More recent guidelines from the American Heart Association suggest that alpha-adrenergic blockers like doxazosin should be avoided in patients with heart failure and hypertension, except when other treatments are inadequate 1. Key points to consider include:

• Doxazosin works by blocking alpha-1 receptors, causing blood vessels to relax and widen, which lowers blood pressure but can also cause side effects like dizziness and orthostatic hypotension.
• If you're currently taking 8 mg of doxazosin, do not stop it suddenly as this could cause a dangerous rebound in blood pressure.
• The medication is typically used to treat high blood pressure and symptoms of benign prostatic hyperplasia, at a dose of 1-8 mg daily.
• If you have existing cardiovascular disease or multiple risk factors, discuss with your healthcare provider whether this medication is appropriate for you or if alternatives might be safer for your specific situation, considering the potential risks and benefits as outlined in recent guidelines 1.

From the FDA Drug Label

Lowering blood pressure reduces the risk of fatal and nonfatal cardiovascular events, primarily strokes and myocardial infarctions. Numerous antihypertensive drugs, from a variety of pharmacologic classes and with different mechanisms of action, have been shown in randomized controlled trials to reduce cardiovascular morbidity and mortality, and it can be concluded that it is blood pressure reduction, and not some other pharmacologic property of the drugs, that is largely responsible for those benefits The largest and most consistent cardiovascular outcome benefit has been a reduction in the risk of stroke, but reductions in myocardial infarction and cardiovascular mortality also have been seen regularly

The use of doxazosin, an alpha-1 adrenergic blocker, lowers blood pressure, which in turn reduces the risk of myocardial infarction (heart attack) and cerebrovascular accident (stroke). Therefore, taking 8 milligrams of doxazosin is likely to decrease, rather than increase, the risk of these events, as part of its blood pressure lowering effect 2.

• Key points:
  • Doxazosin is used to treat hypertension and benign prostatic hyperplasia (BPH)
  • Blood pressure reduction is responsible for the reduction in cardiovascular events
  • Doxazosin may be used alone or in combination with other antihypertensives
• Main benefits:
  • Reduction in the risk of stroke
  • Reduction in the risk of myocardial infarction
  • Reduction in cardiovascular mortality

From the Research

Risk of Myocardial Infarction and Cerebrovascular Accident

• The risk of myocardial infarction (heart attack) and cerebrovascular accident (stroke) associated with taking 8 milligrams of doxazosin is not directly stated in the provided studies.
• However, study 3 found that doxazosin was associated with a significant reduction in morbid and mortal cardiac events, including myocardial infarction, in patients with chronic congestive heart failure.
• Study 4 mentions that doxazosin reduces blood pressure and influences other risk factors of coronary heart disease, but the clinical role of these effects is largely undetermined.
• Study 5 states that doxazosin has favorable effects on the plasma lipid profile, which may help reduce the risk of coronary heart disease.

Effects of Doxazosin on Blood Pressure and Heart Rate

• Study 6 found that doxazosin significantly reduced sitting and standing blood pressure in patients with essential hypertension.
• Study 7 found that doxazosin lowered supine and standing systolic and diastolic blood pressure, and the blood pressure reduction was associated with an increase in heart rate.
• Study 5 states that doxazosin significantly lowers both standing and supine blood pressure, and appears to maintain this antihypertensive effect over a 24-hour dosing interval.

Safety and Tolerability of Doxazosin

• Study 6 found that doxazosin was well tolerated and orthostatic hypotension was never observed.
• Study 7 found that the most frequent side effects of doxazosin were dizziness, headaches, and dry mouth.
• Study 3 found that doxazosin was well tolerated, producing no major side effects and only a slightly higher frequency of minor treatment-related side effects compared with placebo.
• Study 4 states that doxazosin appears to be a valuable add-on antihypertensive treatment option, with a large proportion of patients demonstrating a favorable blood pressure response and relatively few treatment-associated side effects.