From the Guidelines
Neither doxazosin nor tamsulosin (Flomax) is clearly more effective than the other for treating Benign Prostatic Hyperplasia (BPH). Both medications are alpha-1 blockers that work similarly by relaxing smooth muscles in the prostate and bladder neck to improve urine flow and reduce BPH symptoms.
Key Points
- Clinical studies show comparable effectiveness in improving urinary symptoms and flow rates 1.
- However, tamsulosin is often preferred as a first-line treatment because it has fewer cardiovascular side effects like dizziness and low blood pressure compared to doxazosin.
- Tamsulosin is typically dosed at 0.4 mg once daily, while doxazosin usually starts at 1 mg daily and may be titrated up to 4-8 mg daily as needed.
- Tamsulosin is also more selective for the prostate tissue, which contributes to its better side effect profile.
- The choice between these medications should be individualized based on a patient's other medical conditions, potential drug interactions, and tolerance to side effects.
- Both medications take about 2-4 weeks to show maximum benefit, and patients should be monitored for orthostatic hypotension, especially when starting treatment.
Considerations
- According to the 2021 AUA guideline, alpha blockers such as doxazosin and tamsulosin are recommended as a treatment option for patients with bothersome, moderate to severe LUTS/BPH 1.
- The guideline also suggests that the choice of alpha blocker should be based on patient age and comorbidities, and different adverse event profiles.
- It is essential to consider the patient's overall health and medical history when deciding between doxazosin and tamsulosin.
- For example, patients with hypertension may require separate management of their hypertension, as doxazosin monotherapy was associated with a higher incidence of congestive heart failure compared to other antihypertensive agents 1.
From the Research
Comparison of Doxazosin and Tamsulosin (Flomax) for BPH Treatment
- The efficacy of doxazosin and tamsulosin in treating Benign Prostatic Hyperplasia (BPH) has been compared in several studies 2, 3.
- A study published in 2006 found that tamsulosin was more effective than doxazosin in improving lower urinary tract symptoms (LUTS) due to BPH, with significant improvements in maximal urinary flow rates (Qmax), average urinary flow rates (Qave), and residual urine 2.
- Another study published in 2000 compared the efficacy and safety of prazosin, terazosin, and tamsulosin in the treatment of symptomatic BPH, and found that terazosin produced significantly higher improvement in individual symptoms than tamsulosin, while tamsulosin appeared to be safer than the others for aged patients or patients with hypertension 3.
- Doxazosin has been shown to be effective in treating BPH symptoms, including improving AUA total symptom and bothersomeness scores, and BPH-specific indices of health status and interference with activities 4.
- Tamsulosin has also been found to be effective in treating BPH symptoms, with significant improvements in Qmax, symptom scores, and quality of life 5, 6.
Safety and Tolerability
- Both doxazosin and tamsulosin have been found to be well-tolerated, with minimal adverse events reported 4, 2, 3.
- However, doxazosin has been associated with a higher incidence of dizziness and hypotension compared to tamsulosin 4, 2.
- Tamsulosin has been found to have a favorable safety profile, with no significant effects on blood pressure or pulse rate when coadministered with antihypertensive agents 6.