Does doubling the dose of Flomax (tamsulosin) to 8 mg increase the therapeutic benefits for Benign Prostatic Hyperplasia (BPH)?

From the Guidelines

No, taking 8 mg of Flomax (tamsulosin) does not double the benefits for benign prostatic hyperplasia (BPH) and is not recommended. The standard and maximum recommended dose for BPH is 0.4 mg once daily, which may be increased to 0.8 mg once daily if needed after 2-4 weeks. Exceeding the 0.8 mg daily dose does not provide additional therapeutic benefits but significantly increases the risk of side effects such as dizziness, orthostatic hypotension, abnormal ejaculation, and syncope. According to the most recent guideline on management of lower urinary tract symptoms attributed to benign prostatic hyperplasia 1, tamsulosin has a moderate effect on improving IPSS, but there is no evidence to suggest that doubling the dose to 8 mg would provide additional benefits. In fact, the guideline suggests that the effectiveness of tamsulosin reaches a plateau at therapeutic doses, and alternative or additional treatments should be considered if symptoms persist.

Key Points to Consider

• The maximum recommended dose of tamsulosin is 0.8 mg once daily, and exceeding this dose does not provide additional therapeutic benefits 1.
• Doubling the dose of tamsulosin to 8 mg increases the risk of side effects such as dizziness, orthostatic hypotension, abnormal ejaculation, and syncope.
• Tamsulosin works by relaxing smooth muscles in the prostate and bladder neck to improve urine flow, but this effect reaches a plateau at therapeutic doses.
• Alternative or additional treatments, such as 5-alpha-reductase inhibitors (5-ARIs), should be considered if symptoms persist despite maximum recommended doses of tamsulosin 1.

Clinical Implications

• Clinicians should be cautious when considering dose increases beyond the recommended maximum, as this may not provide additional benefits and may increase the risk of adverse effects.
• Patients should be counseled on the potential risks and benefits of treatment and alternative options, and should be monitored closely for adverse effects.
• The relationship between dose and effect is not linear, meaning that doubling the dose beyond recommended levels will not proportionally improve symptoms 1.

From the FDA Drug Label

2 DOSAGE & ADMINISTRATION Tamsulosin Hydrochloride Capsules 0.4 mg once daily is recommended as the dose for the treatment of the signs and symptoms of BPH.

For those patients who fail to respond to the 0. 4 mg dose after 2 to 4 weeks of dosing, the dose of Tamsulosin Hydrochloride Capsules can be increased to 0.8 mg once daily.

The FDA drug label does not support the idea of doubling the dose of Flomax (tamsulosin) to 8 mg for the treatment of Benign Prostatic Hyperplasia (BPH). The recommended dose is 0.4 mg once daily, and it can be increased to 0.8 mg once daily for patients who fail to respond to the initial dose. There is no mention of a dose of 8 mg in the provided drug labels 2 2.

From the Research

Therapeutic Benefits of Doubling the Dose of Flomax (Tamsulosin)

• The study 3 found that tamsulosin improved symptoms and peak urine flow relative to placebo, with a 12% improvement in Boyarsky symptom score for 0.4 mg and 16% improvement for 0.8 mg.
• However, the study 3 also found that adverse effects increased markedly as tamsulosin dosing increased, and were reported in 75% of men receiving the 0.8 mg dose.
• There is no direct evidence in the provided studies to suggest that doubling the dose of Flomax (tamsulosin) to 8 mg increases the therapeutic benefits for Benign Prostatic Hyperplasia (BPH).
• The standard dose of tamsulosin is 0.4 mg or 0.8 mg, and the study 4 found that doubling the dose for the next 2 weeks did not provide significant additional benefits.
• The study 5 found that tamsulosin reduced nighttime urine production in BPH patients with nocturnal polyuria, but this study used a dose of 0.2 mg once daily.

Comparison with Other Treatments

• The study 6 discussed the use of 5-alpha reductase inhibitors (5-ARIs) such as finasteride and dutasteride in the treatment of BPH, and found that they improved voiding symptoms and reduced the risk of urinary retention and prostate surgery.
• The study 7 found that the combination of tamsulosin and finasteride improved lower urinary tract symptoms, maximum urinary flow rate, and prostate volume, but the results were not significantly different from monotherapy.
• The study 4 compared the efficacy and safety of prazosin, terazosin, and tamsulosin in the treatment of BPH, and found that terazosin produced significantly higher improvement in symptomatic score than tamsulosin.