Adverse Effects of Tamsulosin
The primary adverse events reported with tamsulosin therapy are orthostatic hypotension, dizziness, tiredness (asthenia), ejaculatory problems, and nasal congestion, with tamsulosin having a lower probability of orthostatic hypotension but a higher probability of ejaculatory dysfunction compared to other alpha blockers. 1
Common Adverse Effects
Cardiovascular effects: Orthostatic hypotension can occur, especially when changing positions quickly. While tamsulosin has a lower risk of orthostatic hypotension compared to other alpha-blockers, patients should still be cautioned about this potential side effect 1
Central nervous system effects: Dizziness and tiredness (asthenia) are commonly reported adverse events 1, 2
Sexual dysfunction: Ejaculatory problems, including abnormal ejaculation, are among the most common adverse events. This effect is more common with tamsulosin than with other alpha-blockers 1, 2
Respiratory effects: Nasal congestion is a common side effect of tamsulosin therapy 1
Serious Adverse Effects
Syncope: There is a potential risk of syncope (fainting), particularly at the beginning of treatment or when changing doses 2
Priapism: Rarely (probably less than 1 in 50,000 patients), tamsulosin has been associated with priapism (persistent painful penile erection unrelated to sexual activity). This condition can lead to permanent impotence if not properly treated 2
Intraoperative Floppy Iris Syndrome (IFIS): This condition has been observed during cataract and glaucoma surgery in patients on or previously treated with tamsulosin. Most reports were in patients taking the alpha-1 blocker when IFIS occurred, but in some cases, the syndrome appeared after the medication had been discontinued (from 2-14 days to 5 weeks to 9 months) 2
Effects on Sperm Parameters
- Tamsulosin may have negative effects on sperm parameters, including:
- Decreased total sperm count in semen
- Reduced semen viscosity
- Decreased percentage of motile sperm
- Slightly increased percentage of abnormal sperm 3
Drug Interactions
CYP3A4 inhibitors: Tamsulosin should not be used with strong CYP3A4 inhibitors (e.g., ketoconazole) and should be used with caution with moderate inhibitors (e.g., erythromycin) 2
CYP2D6 inhibitors: Caution is advised when using tamsulosin with strong (e.g., paroxetine) or moderate (e.g., terbinafine) CYP2D6 inhibitors, particularly at higher doses 2
Other alpha-blockers: Tamsulosin should not be used in combination with other alpha-adrenergic blocking agents 2
PDE5 inhibitors: Caution is advised when co-administering tamsulosin with PDE5 inhibitors, as both are vasodilators that can potentially cause symptomatic hypotension 2
Warfarin: Caution should be exercised with concomitant administration of warfarin and tamsulosin 2
Antihypertensives: In men with hypertension and cardiac risk factors, alpha-blocker therapy should not necessarily be assumed to constitute optimal management of concomitant hypertension 1
Precautions for Specific Patient Groups
Patients undergoing eye surgery: Patients should inform their surgeon if they take or have taken tamsulosin before undergoing cataract or glaucoma surgery due to the risk of IFIS 2
Patients with hypertension: Separate management of hypertension may be required in patients using tamsulosin for LUTS 1
Patients with renal or liver problems: These conditions should be disclosed to the physician before starting tamsulosin 2
Practical Considerations
Patients should be advised to change positions slowly, particularly when moving from lying down to sitting up or from sitting to standing, until they learn how they react to tamsulosin 2
If dizziness occurs, patients should sit or lie down until they feel better 2
Patients should avoid driving, operating machinery, or other dangerous activities until they know how tamsulosin affects them 2
Tamsulosin should be taken approximately 30 minutes after the same meal each day 2