From the Guidelines
Yes, tamsulosin can cause hypotension, particularly orthostatic hypotension (a drop in blood pressure when standing up). This side effect is more common when starting treatment or increasing the dose. Tamsulosin is an alpha-1 adrenergic receptor blocker that works by relaxing smooth muscles in the prostate and bladder neck, but it also affects blood vessels throughout the body, causing them to dilate and potentially lower blood pressure. The standard dose is 0.4 mg once daily, taken approximately 30 minutes after the same meal each day. To minimize hypotensive effects, patients should start with this dose and take it at bedtime. Elderly patients and those taking other blood pressure medications are at higher risk for this side effect. Patients should be advised to rise slowly from sitting or lying positions, especially during the first few days of treatment. If dizziness or lightheadedness occurs, patients should sit or lie down immediately and avoid driving or hazardous activities until these effects resolve.
According to the 2017 ACC/AHA/AAPA/ABC/ACPM/AGS/APhA/ASH/ASPC/NMA/PCNA guideline for the prevention, detection, evaluation, and management of high blood pressure in adults 1, alpha-1 blockers like doxazosin, prazosin, and terazosin are associated with orthostatic hypotension, especially in older adults. Although tamsulosin is not explicitly mentioned in these guidelines as a cause of hypotension, its mechanism of action as an alpha-1 adrenergic receptor blocker suggests that it may also cause hypotension.
Key points to consider:
- Tamsulosin can cause orthostatic hypotension, especially in older adults and those taking other blood pressure medications.
- Patients should start with a standard dose of 0.4 mg once daily and take it at bedtime to minimize hypotensive effects.
- Patients should be advised to rise slowly from sitting or lying positions, especially during the first few days of treatment.
- If dizziness or lightheadedness occurs, patients should sit or lie down immediately and avoid driving or hazardous activities until these effects resolve.
It is essential to weigh the benefits and risks of tamsulosin treatment and monitor patients closely for signs of hypotension, especially during the initial treatment period.
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. 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, as evidenced by the increased risk of orthostasis and symptomatic hypotension when used alone or in combination with other medications, such as PDE5 inhibitors 2.
- Key points:
- Tamsulosin can cause orthostasis and symptomatic hypotension
- Concomitant use with PDE5 inhibitors can increase the risk of symptomatic hypotension
- Patients should be cautioned to avoid situations in which injury could result should syncope occur 2.
From the Research
Tamsulosin and Blood Pressure
- Tamsulosin is a subtype-selective alpha(1A)- and alpha(1D)-adrenoceptor antagonist used to treat lower urinary tract symptoms (LUTS) associated with benign prostatic hyperplasia (BPH) 3.
- Studies have shown that tamsulosin does not significantly decrease blood pressure or cause hypotensive effects in patients with BPH 3, 4.
- In fact, tamsulosin has been found to have a low potential for hypotensive effects compared to other alpha(1)-adrenoceptor antagonists 3, 5.
- A study comparing tamsulosin and terazosin found that tamsulosin had a lower incidence of symptomatic hypotensive orthostatic testing (OT) and asymptomatic exaggerated decrease in systolic blood pressure 5.
- Tamsulosin has also been shown to be safe and effective in patients with hypertension and BPH, with no adverse interaction with other antihypertensive medications or low-dose diuretics 6.
- A systematic review of 14 studies involving 4,122 subjects found that tamsulosin improved symptoms and peak urine flow relative to placebo, with a low incidence of adverse effects, including dizziness, rhinitis, and abnormal ejaculation 7.
Orthostatic Hypotension
- Orthostatic hypotension is a potential side effect of alpha(1)-adrenoceptor antagonists, but studies have shown that tamsulosin has a low risk of causing this condition 4, 5.
- A study found that tamsulosin did not induce a higher risk of orthostatic hypotension than placebo in patients with BPH 4.
- Another study found that tamsulosin had a lower incidence of symptomatic hypotensive OT and asymptomatic exaggerated decrease in systolic blood pressure compared to terazosin 5.