From the Guidelines
Patients taking tamsulosin can generally take sildenafil, but caution is advised due to potential additive blood pressure-lowering effects when these medications are combined. Both medications can cause vasodilation - tamsulosin primarily affects blood vessels in the prostate and bladder neck while sildenafil causes more widespread vasodilation. This combination may lead to symptomatic hypotension (low blood pressure), particularly when starting either medication or increasing the dose. According to the most recent study 1, the management of non-neurogenic male lower urinary tract symptoms should consider the potential interactions between different medications. Some key points to consider when taking these medications together include:
- Separating the timing of these medications when possible to minimize the risk of hypotension
- Being aware of symptoms like dizziness, lightheadedness, or fainting
- Starting with a lower dose of sildenafil (25mg) when already on tamsulosin
- Avoiding this combination if patients have uncontrolled low blood pressure, are taking other antihypertensive medications, or have severe heart or liver disease
- Seeking medical attention immediately if symptoms of hypotension occur and are severe or persistent. The American College of Physicians recommends that clinicians initiate therapy with a PDE-5 inhibitor, such as sildenafil, in men who seek treatment for erectile dysfunction and who do not have a contraindication to PDE-5 inhibitor use 1. However, the potential risks and benefits of combining tamsulosin and sildenafil should be carefully considered, and patients should be closely monitored for any adverse effects.
From the FDA Drug Label
Caution is advised when alpha adrenergic blocking agents including Tamsulosin Hydrochloride Capsules are co-administered with PDE5 inhibitors. Alphaadrenergic blockers and PDE5 inhibitors are both vasodilators that can lower blood pressure. Concomitant use of these two drug classes can potentially cause symptomatic hypotension
The patient taking tamsulosin (alpha-blocker) can take sildenafil (phosphodiesterase type 5 inhibitor) but with caution due to the potential risk of symptomatic hypotension. 2 2
From the Research
Patient Considerations
- Patients taking tamsulosin (alpha-blocker) can take sildenafil (phosphodiesterase type 5 inhibitor), but precautions are necessary due to the potential for additive hypotensive effects 3, 4, 5.
- The interaction between alpha-blockers and PDE5 inhibitors may be less relevant clinically if the patient has been undergoing long-term alpha-blocker therapy 4.
- Patients should be stable on alpha-blocker therapy before initiating sildenafil treatment, and sildenafil should be initiated at the lowest dose 5.
Safety Considerations
- Sildenafil can cause a mild decrease in systemic arterial pressure, and its administration to patients taking organic nitrates is contraindicated due to the risk of synergistic hypotension 6, 4, 5, 7.
- The risk of serious cardiovascular adverse events, myocardial infarction, or death is not increased with sildenafil use compared to placebo 5, 7.
- Physicians should carefully consider whether their patients with underlying cardiovascular disease could be affected adversely by resuming sexual activity 5.
Dosage Considerations
- Sildenafil dosages usually begin at 50mg taken when needed, at least 1 hour before sexual activity, and no more than once daily 6.
- The maximum dose is 100mg when needed once daily, and lower doses (e.g., 25mg) may be used in elderly patients or those with hepatic or renal impairment 6.
- When coadministering sildenafil with an alpha-blocker, patients should be stable on alpha-blocker therapy before initiating sildenafil treatment, and sildenafil should be initiated at the lowest dose 5.