What is the recommended dosage and use of doxazosin for treating high blood pressure and benign prostatic hyperplasia (BPH)?

From the Guidelines

Doxazosin is typically started at a low dose of 1 mg once daily, usually taken at bedtime, with gradual increases as needed for both hypertension and BPH. For high blood pressure, the dose may be increased to 2 mg, 4 mg, and up to a maximum of 8 mg daily, with adjustments made every 1-2 weeks based on blood pressure response 1. For BPH, the maintenance dose usually ranges from 4-8 mg once daily. It's essential to take the first dose at bedtime due to the risk of first-dose hypotension, which can cause dizziness or fainting. Patients should avoid situations that might be dangerous if these symptoms occur, such as driving, for 24 hours after the initial dose or dose increases. Doxazosin works by relaxing blood vessels and smooth muscle in the prostate and bladder neck, improving blood flow and reducing urinary symptoms. The medication should be taken consistently at the same time each day, and patients should not stop taking it without consulting their healthcare provider, even if they feel better. Full therapeutic effects may take 3-4 weeks to develop, particularly for BPH symptoms. Some key points to consider when using doxazosin include:

• The risk of orthostatic hypotension, especially in older adults 1
• The potential for doxazosin to be used as a second-line agent in patients with concomitant BPH 1
• The importance of monitoring blood pressure and adjusting the dose as needed to minimize the risk of hypotension and other adverse effects. Overall, doxazosin is an effective treatment option for both hypertension and BPH, but it's crucial to use it judiciously and monitor patients closely to minimize the risk of adverse effects.

From the FDA Drug Label

2.1 Dosing Information Following the initial dose and with each dose increase of doxazosin tablets, monitor blood pressure for at least 6 hours following administration. If doxazosin tablets administration is discontinued for several days, therapy should be restarted using the initial dosing regimen. 2. 2 Benign Prostatic Hyperplasia The recommended initial dosage of doxazosin tablets is 1 mg given once daily either in the morning or evening. Depending on the individual patient’s urodynamics and BPH symptomatology, the dose may be titrated at 1 to 2 week intervals to 2 mg, and thereafter to 4 mg and 8 mg once daily. The maximum recommended dose for BPH is 8 mg once daily. Routinely monitor blood pressure in these patients. 2. 3 Hypertension The initial dosage of doxazosin tablets is 1 mg given once daily. Daily dosage may be doubled up 16 mg once daily, as needed, to achieve the desired reduction in blood pressure.

The recommended dosage and use of doxazosin for treating high blood pressure and benign prostatic hyperplasia (BPH) are as follows:

• For BPH: The initial dose is 1 mg once daily, which may be titrated to 2 mg, 4 mg, and 8 mg once daily, with a maximum recommended dose of 8 mg once daily.
• For hypertension: The initial dose is 1 mg once daily, which may be doubled up to 16 mg once daily as needed to achieve the desired reduction in blood pressure. Key points to consider:
• Monitor blood pressure for at least 6 hours after the initial dose and each dose increase.
• Titrate the dose based on individual patient response and urodynamics for BPH.
• Restart therapy using the initial dosing regimen if doxazosin administration is discontinued for several days 2.

From the Research

Dosage and Use of Doxazosin

• The recommended dosage of doxazosin for treating high blood pressure and benign prostatic hyperplasia (BPH) varies, but studies have shown that doses of 1-16 mg once daily are effective 3.
• A long-term study found that the mean daily doses of doxazosin were 4 mg for normotensive men and 6.4 mg for hypertensive men, with significant improvements in urinary flow rates and BPH symptoms 4.
• Another study found that doxazosin produced a significant increase in maximum urinary flow rate at doses of 4 mg, 8 mg, and 12 mg, and in average flow rate at doses of 8 mg and 12 mg, compared with placebo 5.

Efficacy and Safety of Doxazosin

• Doxazosin has been shown to be effective and safe in the treatment of BPH in normotensive and hypertensive patients, with significant improvements in urodynamic and symptomatic parameters 3.
• A study found that doxazosin was well tolerated, with almost 90% of adverse experiences considered mild or moderate in severity, and the most common adverse events were dizziness, headache, and fatigue 4.
• Doxazosin has also been found to have a beneficial effect on some risk factors associated with coronary heart disease, including elevated serum lipid levels, impaired glucose metabolism, and left ventricular hypertrophy 6.

Clinical Applications of Doxazosin

• Doxazosin is a promising agent in the treatment of urinary symptoms associated with BPH, with increases in peak and mean urinary flow rates and improvements in other objective and symptomatic measures 6.
• Doxazosin may be particularly useful in the management of patients who have BPH and hypertension, as it can address both conditions simultaneously 7, 5.
• The use of doxazosin has been supported by several studies, which have demonstrated its efficacy and safety in a variety of patient populations, including the elderly, blacks, smokers, and patients with concomitant disease states 6.