From the Guidelines
Tamsulosin works by relaxing muscles in the prostate and bladder neck to improve urine flow in men with benign prostatic hyperplasia (BPH). It is an alpha-1 adrenergic receptor blocker that specifically targets the alpha-1A receptors found predominantly in the prostate. When these receptors are blocked, the smooth muscle tissue in the prostate and bladder neck relaxes, reducing the pressure on the urethra and allowing urine to flow more freely.
Key Points
- Tamsulosin is typically prescribed at a dose of 0.4 mg once daily, taken about 30 minutes after the same meal each day, as stated in the study by 1.
- Some patients may require dose adjustment to 0.8 mg daily if needed, as noted in the study by 1.
- The medication begins working within 2-4 days, though full effects may take up to 2-4 weeks.
- Unlike older alpha blockers, tamsulosin has less effect on blood pressure because of its selectivity for urinary tract receptors, making it less likely to cause dizziness or fainting, as mentioned in the study by 1.
- Patients should swallow the capsule whole and not crush or chew it, as this affects the controlled release mechanism of the medication.
Mechanism of Action
The mechanism of action of tamsulosin involves the blockade of alpha-1A receptors in the prostate, which leads to a decrease in smooth muscle tone and a subsequent increase in urine flow, as explained in the study by 1.
Clinical Evidence
The clinical evidence supporting the use of tamsulosin for BPH is based on several studies, including the one by 1, which demonstrated the efficacy and safety of tamsulosin in improving symptoms and quality of life in men with BPH.
Dosage and Administration
The recommended dosage of tamsulosin is 0.4 mg once daily, as stated in the study by 1.
Conclusion is not allowed, so the text is ended here.
From the FDA Drug Label
The symptoms associated with benign prostatic hyperplasia (BPH) are related to bladder outlet obstruction, which is comprised of two underlying components: static and dynamic. The static component is related to an increase in prostate size caused, in part, by a proliferation of smooth muscle cells in the prostatic stroma However, the severity of BPH symptoms and the degree of urethral obstruction do not correlate well with the size of the prostate. The dynamic component is a function of an increase in smooth muscle tone in the prostate and bladder neck leading to constriction of the bladder outlet Smooth muscle tone is mediated by the sympathetic nervous stimulation of alpha 1 adrenoceptors, which are abundant in the prostate, prostatic capsule, prostatic urethra, and bladder neck. Blockade of these adrenoceptors can cause smooth muscles in the bladder neck and prostate to relax, resulting in an improvement in urine flow rate and a reduction in symptoms of BPH Tamsulosin, an alpha 1 adrenoceptor blocking agent, exhibits selectivity for alpha 1 receptors in the human prostate.
Tamsulosin works by blocking alpha 1 adrenoceptors, which are responsible for the smooth muscle tone in the prostate and bladder neck. This blockade causes the smooth muscles to relax, resulting in an improvement in urine flow rate and a reduction in symptoms of BPH. The key points are:
- Alpha 1 adrenoceptors are abundant in the prostate, prostatic capsule, prostatic urethra, and bladder neck.
- Blockade of alpha 1 adrenoceptors causes smooth muscles to relax.
- Tamsulosin exhibits selectivity for alpha 1 receptors in the human prostate. 2
From the Research
Mechanism of Action
- Tamsulosin is a subtype-selective alpha(1A)- and alpha(1D)-adrenoceptor antagonist, which means it blocks the action of certain chemicals in the body that cause the muscles in the prostate and bladder to contract 3, 4, 5.
- By relaxing the muscles in the prostate and bladder, tamsulosin improves the flow of urine and reduces the symptoms of benign prostatic hyperplasia (BPH) 3, 4, 5.
Efficacy
- Tamsulosin has been shown to be effective in improving the symptoms of BPH, including increasing the maximum urine flow rate and reducing the symptoms of lower urinary tract symptoms (LUTS) 3, 4, 5.
- The drug has been shown to be effective in patients with mild to severe LUTS, patients with diabetes mellitus, and patients aged 65 years or older 3, 4, 5.
- Tamsulosin has also been shown to be effective in combination with other medications, such as dutasteride, in the treatment of BPH 6.
Safety and Tolerability
- The most common adverse events associated with tamsulosin are dizziness, abnormal ejaculation, and rhinitis-like complaints 3, 4, 5.
- Tamsulosin has been shown to have a low potential for hypotensive effects and does not interfere with concomitant antihypertensive therapy 3, 4, 5.
- The drug has been shown to be well tolerated in patients with BPH, with a low incidence of adverse events and no significant changes in blood pressure 3, 4, 5.