From the Guidelines
Tamsulosin can lower blood pressure as a side effect, though it's primarily used to treat benign prostatic hyperplasia (BPH) rather than hypertension. When taken at the standard dose of 0.4 mg daily, tamsulosin may cause orthostatic hypotension, particularly when starting treatment or increasing the dose. This means patients might experience dizziness, lightheadedness, or fainting when standing up quickly. The blood pressure-lowering effect occurs because tamsulosin selectively blocks alpha-1A receptors in the prostate and also affects alpha-1 receptors in blood vessels, causing vasodilation. This effect is usually mild in most patients but can be more pronounced in those who are already taking other blood pressure medications, are elderly, or are volume-depleted. Patients should take tamsulosin at bedtime to minimize these effects and should rise slowly from sitting or lying positions. If experiencing significant dizziness or fainting, patients should contact their healthcare provider, as dose adjustment or medication changes may be necessary, as supported by the latest guidelines on hypertension management 1. Additionally, the European guidelines on cardiovascular disease prevention in clinical practice also discuss the importance of considering the effects of antihypertensive drugs on blood pressure and cardiovascular risk, which is relevant to the use of tamsulosin in patients with BPH 1. It is also worth noting that the management of BPH and its symptoms, including the use of alpha-1 blockers like tamsulosin, is discussed in the European Association of Urology guidelines, which provide recommendations for the treatment of lower urinary tract symptoms in men 1. Some key points to consider when prescribing tamsulosin include:
- Starting with a low dose and gradually increasing as needed
- Monitoring blood pressure and adjusting the dose or adding other medications as necessary
- Counseling patients on the potential side effects of orthostatic hypotension and how to manage them
- Considering the use of tamsulosin in combination with other medications for BPH or hypertension, as supported by the guidelines 1.
From the FDA Drug Label
The signs and symptoms of orthostasis (postural hypotension, dizziness, and vertigo) were detected more frequently in Tamsulosin Hydrochloride Capsules -treated patients than in placebo recipients. Caution is advised when alpha adrenergic blocking agents, including Tamsulosin Hydrochloride Capsules, are co-administered with PDE5 inhibitors. Alpha-adrenergic blockers and PDE5 inhibitors are both vasodilators that can lower blood pressure. Concomitant use of these two drug classes can potentially cause symptomatic hypotension
Tamsulosin can cause a decrease in blood pressure, particularly orthostatic hypotension. Caution is advised when using tamsulosin, especially in combination with other medications that can lower blood pressure, such as PDE5 inhibitors.
- Orthostatic hypotension is a potential side effect of tamsulosin.
- Symptomatic hypotension can occur when tamsulosin is used with PDE5 inhibitors. 2 2
From the Research
Tamsulosin Effect on Blood Pressure
- Tamsulosin is a subtype-selective alpha(1A)- and alpha(1D)-adrenoceptor antagonist, which is effective in the treatment of lower urinary tract symptoms (LUTS) associated with benign prostatic hyperplasia (BPH) 3.
- Studies have shown that tamsulosin has minimal effects on blood pressure, with no clinically significant changes in blood pressure observed in clinical trials 3, 4.
- Compared to other alpha(1)-adrenoceptor antagonists, such as alfuzosin and terazosin, tamsulosin has a lower potential to cause hypotensive effects 4, 5.
- A study comparing tamsulosin and terazosin found that tamsulosin had no significant effect on finger tip vasoconstrictor response to cold stimulation and vasoconstrictor response of the dorsal hand vein to increasing doses of phenylephrine, suggesting that tamsulosin exerts little alpha(1)-adrenoceptor-blocking activity on blood vessels 5.
- Orthostatic tests have shown that tamsulosin does not induce a higher risk of orthostatic hypotension than placebo, and the incidence of hypotension and syncope is extremely low in community-dwelling elderly men treated with tamsulosin for BPH 6.
- A double-blind comparison of terazosin and tamsulosin found that tamsulosin had a more favorable effect on ambulatory blood pressure and nocturnal orthostatic stress testing, with fewer incidents of symptomatic hypotensive orthostatic testing 7.