Indication for Flomax (Tamsulosin)
Tamsulosin is specifically indicated for the treatment of signs and symptoms of benign prostatic hyperplasia (BPH). 1
Mechanism of Action and Pharmacology
- Tamsulosin is an alpha-1 adrenoceptor antagonist that selectively blocks alpha-1A and alpha-1D adrenoceptors, which predominate in the prostate gland, prostatic capsule, prostatic urethra, and bladder 2
- By inhibiting alpha-1-adrenergic-mediated contraction of prostatic smooth muscle, tamsulosin helps relieve bladder outlet obstruction, improving urinary flow and reducing lower urinary tract symptoms 2, 3
- Tamsulosin demonstrates greater selectivity for prostatic alpha-1 receptors compared to vascular alpha-1 receptors, resulting in a lower risk of orthostatic hypotension compared to other alpha blockers 2, 4
Clinical Efficacy
- Tamsulosin 0.4 mg once daily in a modified-release formulation has been shown to significantly improve maximum urinary flow rate (Qmax) and reduce symptom scores compared to placebo 5, 6
- Clinical studies demonstrate a rapid decrease in AUA Symptom Scores starting at 1 week after dosing, with benefits maintained through 13 weeks and beyond 1, 6
- Long-term studies indicate maintenance of efficacy for up to 6 years with continued tamsulosin treatment 3
- Tamsulosin improves both obstructive and irritative symptoms of BPH, including nocturia and hesitancy 5, 7
Dosing Considerations
- The standard dosage of tamsulosin is 0.4 mg once daily in a modified-release formulation 8
- Unlike some other alpha blockers, tamsulosin does not require initial dose titration, making it more convenient for patients 8, 3
- Tamsulosin can be administered after a meal to improve tolerability 7
Important Clinical Considerations and Limitations
- Tamsulosin is NOT indicated for the treatment of hypertension 1
- Tamsulosin does not affect prostate size and should not be used to reduce prostate volume 8
- The most common adverse effects specific to tamsulosin include ejaculatory dysfunction (4.5-14.0% of patients), which occurs at a higher rate than with other alpha blockers 2, 3
- Tamsulosin is associated with intraoperative floppy iris syndrome (IFIS) during cataract surgery, which is an important consideration for patients planning ophthalmic procedures 8, 2
- Patients should inform their ophthalmologists about tamsulosin use before undergoing cataract surgery 8
Clinical Advantages
- Tamsulosin has a lower potential for hypotensive effects compared to non-selective alpha blockers 3, 4
- It generally does not interfere with concomitant antihypertensive therapy 3
- Tamsulosin is effective across a range of BPH severity (mild to severe) and in special populations including elderly patients and those with diabetes mellitus 3, 6