What is the dosage and treatment regimen for Cardura (doxazosin) in managing hypertension and benign prostatic hyperplasia (BPH)?

From the Guidelines

Cardura (doxazosin) should be initiated at a low dose of 1 mg once daily, taken at bedtime, for both hypertension and BPH, with gradual increases based on patient response, up to a maximum of 16 mg daily for hypertension and 8 mg daily for BPH. The dosage and treatment regimen for Cardura (doxazosin) in managing hypertension and benign prostatic hyperplasia (BPH) can be guided by the most recent evidence from the 2017 ACC/AHA/AAPA/ABC/ACPM/AGS/APhA/ASH/ASPC/NMA/PCNA guideline for the prevention, detection, evaluation, and management of high blood pressure in adults 1.

Key Considerations

• The dose can be titrated every 1-2 weeks based on patient response, with most patients requiring 4-8 mg daily for adequate blood pressure control.
• For BPH, the dose is typically titrated up to 4-8 mg once daily, with a maximum recommended dose of 8 mg.
• Taking the medication at bedtime helps minimize the risk of first-dose hypotension and syncope, which are common side effects.
• Patients should be advised to avoid situations where injury could occur if syncope develops, especially during initial dosing and dose increases.
• Doxazosin works by blocking alpha-1 adrenergic receptors, causing vasodilation to lower blood pressure and relaxing smooth muscle in the prostate and bladder neck to improve urinary symptoms in BPH.
• The medication can be taken with or without food, and patients should maintain consistent timing of doses.
• Blood pressure monitoring is essential during dose adjustments, and improvement in BPH symptoms may take 1-2 weeks to become noticeable.

Additional Guidance

• According to the AUA guideline on management of benign prostatic hyperplasia (2003), doxazosin is an appropriate treatment option for patients with LUTS secondary to BPH, with equal clinical effectiveness to other alpha-blockers such as alfuzosin, tamsulosin, and terazosin 1.
• The guideline also notes that the use of alpha-blocker therapy is based on the hypothesis that clinical BPH is partly caused by alpha1-adrenergic-mediated contraction of prostatic smooth muscle, resulting in bladder outlet obstruction.
• In men with hypertension and cardiac risk factors, doxazosin monotherapy was associated with a higher incidence of congestive heart failure than seen with other antihypertensive agents, and therefore, separate management of hypertension may be necessary in these cases.

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 dosage and treatment regimen for Cardura (doxazosin) is as follows:

• For Benign Prostatic Hyperplasia (BPH):
  • Initial dose: 1 mg once daily
  • Titration: increase dose at 1 to 2 week intervals to 2 mg, 4 mg, and 8 mg once daily as needed
  • Maximum dose: 8 mg once daily
• For Hypertension:
  • Initial dose: 1 mg once daily
  • Titration: double dose as needed up to 16 mg once daily to achieve desired blood pressure reduction 2

From the Research

Dosage and Treatment Regimen for Cardura (Doxazosin)

The dosage and treatment regimen for Cardura (doxazosin) in managing hypertension and benign prostatic hyperplasia (BPH) can be summarized as follows:

• The starting dose of doxazosin is typically 1 mg/day, which can be increased at 2-week intervals to 2 mg/day and 4 mg/day as needed and tolerated 3, 4, 5.
• The mean daily doses of doxazosin used in clinical trials for BPH were 4 mg and 6.4 mg for normotensive and hypertensive men, respectively 4.
• Doxazosin can be used as monotherapy for controlling both BPH and hypertension in patients with mild to moderate hypertension 3.
• The addition of doxazosin to another antihypertensive drug in hypertensive patients with BPH is well tolerated and leads to a reduction in prostatic symptoms and improvement in blood pressure control 5.
• A controlled-release gastrointestinal therapeutic system (GITS) formulation of doxazosin is available, which can be titrated through one step and may cause less adverse effects than the standard preparation 6.

Efficacy of Doxazosin in BPH and Hypertension

The efficacy of doxazosin in BPH and hypertension can be summarized as follows:

• Doxazosin significantly improves BPH symptoms, including obstructive and irritative symptoms, and increases peak urinary flow rate 3, 4, 7.
• Doxazosin reduces blood pressure in hypertensive patients, with significant decreases in systolic and diastolic blood pressure 3, 4, 7, 5.
• The combination of doxazosin with other antihypertensive agents can provide additional blood pressure lowering effects 3, 5.

Safety and Tolerability of Doxazosin

The safety and tolerability of doxazosin can be summarized as follows:

• Doxazosin is generally well tolerated, with common adverse effects including dizziness, headache, and fatigue 3, 4, 7, 5.
• The incidence of adverse effects is higher in older patients and those with lower blood pressure 5.
• Doxazosin can be used safely in patients with BPH and hypertension, with a low risk of significant adverse effects 3, 4, 7, 5.