Vardenafil and Silodosin: Can They Be Taken Together?

Vardenafil and Silodosin: Understanding the Interaction

Published: 4 November 2026

Vardenafil and silodosin can be taken together, but only under careful medical supervision because both medicines lower blood pressure and the combination increases the risk of dizziness or fainting. Vardenafil is a PDE5 inhibitor used to treat erectile dysfunction, while silodosin is an alpha-blocker prescribed for urinary symptoms caused by an enlarged prostate. If you're already stable on silodosin, your prescriber will usually start you on the lowest dose of vardenafil and monitor you closely for side effects.

What is vardenafil and what does it do?

Vardenafil (the generic version of Levitra) is a prescription medicine licensed in the UK to treat erectile dysfunction in adult men [5]. It belongs to a group of medicines called PDE5 inhibitors, which work by relaxing blood vessels in the penis, allowing more blood to flow in when you're sexually aroused. This helps you get and keep an erection suitable for sexual activity.

Vardenafil is available in 5mg, 10mg and 20mg tablets. You take it about 25 to 60 minutes before you plan to have sex, and it works only when you're sexually stimulated [5]. The effect can last for several hours, but you should not take more than one dose in 24 hours. Like all PDE5 inhibitors, vardenafil also has a mild blood-pressure-lowering effect throughout your body, which is why interactions with other blood-pressure medicines matter.

At Cured Pharmacy, vardenafil is available on prescription after an online consultation with a UK-registered prescriber. The prescriber will review your medical history, current medicines and overall health to make sure vardenafil is safe and suitable for you.

What is silodosin and why is it prescribed?

Silodosin is an alpha-blocker medicine prescribed to treat the urinary symptoms of benign prostatic hyperplasia (BPH), which is a non-cancerous enlargement of the prostate gland. These symptoms include difficulty starting to urinate, a weak stream, needing to urinate frequently or urgently, and getting up at night to pass urine. Silodosin works by relaxing the smooth muscle in the prostate and bladder neck, making it easier to urinate.

Alpha-blockers like silodosin also relax blood vessels, which can lower your blood pressure. This effect is usually mild, but it's the reason why combining silodosin with vardenafil requires caution. Other alpha-blockers used for similar purposes include tamsulosin, alfuzosin, doxazosin, terazosin, prazosin and indoramin. All of these medicines share the same interaction risk with PDE5 inhibitors.

Many men with BPH also experience erectile dysfunction, so it's not uncommon to need treatment for both conditions. The good news is that with the right precautions and medical oversight, both can be managed safely.

How do vardenafil and silodosin interact?

Vardenafil and silodosin both lower blood pressure through different mechanisms, and when taken together, these effects can add up. Vardenafil relaxes blood vessels in the penis and elsewhere in the body, while silodosin relaxes smooth muscle in the prostate and blood vessels. The combined effect can lead to a more significant drop in blood pressure than either medicine would cause on its own, increasing the risk of dizziness, light-headedness or fainting, especially when you stand up quickly (a reaction called postural hypotension) [3][5].

This interaction is well recognised and is not an absolute contraindication—meaning the two medicines are not forbidden together—but it does require careful management. The British National Formulary advises that patients should be stable on alpha-blocker therapy before starting a PDE5 inhibitor, and that the PDE5 inhibitor should be started at the lowest possible dose [5]. Your prescriber will check that you've been taking silodosin for a while without problems before considering vardenafil.

It's important to be honest during your consultation about all the medicines you take, including over-the-counter products and herbal remedies, so your prescriber can assess the full picture and adjust doses if needed.

What happens in your body when you take both medicines?

When you take silodosin regularly, it keeps the muscle in your prostate and bladder neck relaxed, and it also has a mild relaxing effect on blood vessels. When you then take vardenafil before sex, it adds its own blood-vessel-relaxing effect. Your body's usual mechanisms for maintaining steady blood pressure—such as tightening blood vessels when you stand up—may not work as well, so you might feel dizzy or unsteady, particularly in the first few hours after taking vardenafil. This is why starting on a low dose and monitoring how you feel is so important.

What does your prescriber check before combining vardenafil and silodosin?

Before prescribing vardenafil to someone taking silodosin, a UK prescriber will review several key points. First, they'll confirm that you've been on a stable dose of silodosin for at least a few weeks and that you're not experiencing troublesome side effects such as dizziness or low blood pressure. They'll ask about your blood pressure readings and whether you have any history of fainting or postural hypotension.

The prescriber will also check for other medicines or health conditions that might add to the blood-pressure-lowering effect or otherwise interact with vardenafil. This includes other blood-pressure medicines, nitrates (which are an absolute contraindication with vardenafil), and potent CYP3A4 inhibitors that can raise vardenafil levels in your blood. Vardenafil is contraindicated or requires dose adjustment with medicines such as ritonavir, cobicistat, ketoconazole, itraconazole and clarithromycin [5].

Your cardiovascular fitness is also important. PDE5 inhibitors are not suitable if sexual activity itself is inadvisable—for example, if you've had a recent heart attack or stroke, have unstable angina, or severe heart failure [2][5]. The prescriber will ask about chest pain, breathlessness and your general ability to exercise. If vardenafil is appropriate, you'll usually be started on the lowest dose (5mg) and advised to monitor for dizziness or light-headedness.

Why the lowest dose matters

Starting with vardenafil 5mg minimises the blood-pressure-lowering effect while still offering benefit for erectile dysfunction. If the 5mg dose works well and you tolerate it without dizziness, your prescriber may consider increasing the dose to 10mg or 20mg in future consultations. Never increase the dose yourself or take vardenafil more often than prescribed, as this raises the risk of side effects and interactions.

Practical advice for taking vardenafil and silodosin together

If your prescriber has confirmed it's safe for you to take vardenafil alongside silodosin, follow these practical steps to reduce the risk of side effects. Take your silodosin at the same time each day as prescribed (usually once daily), so your body gets used to a steady level of the medicine. When you plan to use vardenafil, take it about 25 to 60 minutes before sexual activity, and start with the lowest dose your prescriber has recommended [5].

Be cautious when standing up, especially in the first few hours after taking vardenafil. Get up slowly from sitting or lying down, and sit on the edge of the bed for a moment before standing. Avoid heavy alcohol on the day you take vardenafil, as alcohol also lowers blood pressure and can make dizziness worse. It can also impair your ability to get an erection, reducing the effectiveness of the treatment.

If you feel dizzy, light-headed or faint after taking vardenafil, sit or lie down until the feeling passes. If it's severe or doesn't improve, contact your GP or call NHS 111 for advice. Do not drive or operate machinery if you feel unsteady. Keep a note of any side effects and mention them at your next consultation, so your prescriber can adjust your treatment if needed.

Warning signs and when to seek urgent help

Most men tolerate the combination of vardenafil and silodosin well, but you should know the warning signs that need urgent medical attention. If you experience chest pain or discomfort during or after sex, stop what you're doing, sit down and rest. Do not take nitrate medicines such as GTN spray if you've used vardenafil in the past 24 hours, as the combination can cause a dangerous drop in blood pressure. Call 999 and tell the paramedics you've taken vardenafil [3][5].

Seek urgent help if you have an erection that lasts longer than four hours (priapism), even if it's not painful. This is a medical emergency that requires treatment to prevent permanent damage to the penis. Similarly, sudden loss of vision in one or both eyes, or sudden decrease or loss of hearing (sometimes with ringing in the ears or dizziness), requires immediate medical assessment—stop taking vardenafil and go to A&E [5].

If you experience severe dizziness, fainting or a very fast or irregular heartbeat after taking vardenafil with silodosin, seek same-day medical advice. These symptoms may indicate that your blood pressure has dropped too much. Always be open with healthcare professionals about all the medicines you're taking, so they can give you the safest and most effective care.

What about other alpha-blockers?

The advice for vardenafil and silodosin applies equally to other alpha-blockers such as tamsulosin, alfuzosin, doxazosin, terazosin, prazosin and indoramin. All of these medicines can interact with PDE5 inhibitors in the same way, so the same precautions—being stable on the alpha-blocker, starting the PDE5 inhibitor at the lowest dose, and monitoring for dizziness—are essential. Your prescriber will check which alpha-blocker you're taking and adjust your treatment plan accordingly.

Scientific References

1. National Institute for Health and Care Excellence. (n.d.). Erectile dysfunction. Clinical Knowledge Summaries. https://cks.nice.org.uk/topics/erectile-dysfunction/ [accessed 4 November 2026]
2. Joint Formulary Committee. (n.d.). Sildenafil. British National Formulary. NICE. https://bnf.nice.org.uk/drugs/sildenafil/ [accessed 4 November 2026]
3. Joint Formulary Committee. (n.d.). Vardenafil. British National Formulary. NICE. https://bnf.nice.org.uk/drugs/vardenafil/ [accessed 4 November 2026]
4. NHS. (n.d.). Erectile dysfunction (impotence). https://www.nhs.uk/conditions/erection-problems-erectile-dysfunction/ Accessed 4 November 2026.

Information on this page is for educational purposes only and is not medical advice. Prescription treatments require clinical assessment by a UK-registered prescriber. Always consult a qualified healthcare professional before starting or changing any medication.

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