Vardenafil and Aliskiren: Can You Take Them Together?
Learn how these medicines interact and what your prescriber checks during your UK pharmacist-led consultation.
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Vardenafil and Aliskiren: Understanding the Interaction
Published: 27 October 2026
Vardenafil and aliskiren can generally be taken together, but this combination requires careful monitoring because both medicines can lower blood pressure. Vardenafil is a PDE5 inhibitor used to treat erectile dysfunction, while aliskiren is a renin inhibitor prescribed for high blood pressure. When used together, they may cause an additive blood-pressure-lowering effect, which can lead to dizziness or light-headedness. Your prescriber will assess your individual circumstances, current blood pressure control, and overall health before approving this combination.
Start Low, Go Slow
If you're taking aliskiren or any blood pressure medicine, your prescriber may start you on the lowest dose of vardenafil (5 mg) to minimise the risk of dizziness. You can always increase the dose later if needed and if it's safe to do so.
What Is Vardenafil and How Does It Work?
Vardenafil (also known by the brand name Levitra) is a prescription medicine used to treat erectile dysfunction in men. It belongs to a group of medicines called PDE5 inhibitors, which work by relaxing blood vessels in the penis, allowing increased blood flow when you are sexually aroused [5]. Vardenafil does not cause an erection on its own—sexual stimulation is still needed.
The usual dose is 10 mg, taken about 25–60 minutes before sexual activity, though your prescriber may adjust this to 5 mg or 20 mg depending on how well it works and whether you experience side effects [5]. You should not take vardenafil more than once in 24 hours. Common side effects include headache, flushing, indigestion, and nasal congestion.
Because vardenafil can lower blood pressure slightly, it is important to tell your prescriber about all other medicines you take, especially those for high blood pressure, heart conditions, or any other chronic health problems. Your prescriber will review your medical history and current medication list during your online consultation to ensure vardenafil is safe and suitable for you.
What Is Aliskiren and Why Is It Prescribed?
Aliskiren is a prescription medicine used to treat high blood pressure (hypertension). It works by blocking renin, an enzyme produced by the kidneys that plays a key role in regulating blood pressure. By inhibiting renin, aliskiren helps to relax and widen blood vessels, which lowers blood pressure and reduces the strain on your heart.
Aliskiren is usually taken once daily, with or without food, and is often prescribed when other blood pressure medicines (such as ACE inhibitors or angiotensin receptor blockers) are not suitable or have not worked well enough. It may also be used in combination with other antihypertensive medicines to achieve better blood pressure control.
Like all blood pressure medicines, aliskiren can cause side effects, including dizziness, diarrhoea, and low blood pressure, especially when you first start treatment or if the dose is increased. It is important to have your blood pressure monitored regularly and to report any unusual symptoms to your GP or prescriber.
When to get urgent help
- Erection lasting more than 4 hours (priapism) – go to A&E immediately
- Sudden loss of vision or hearing – stop vardenafil and seek urgent medical help
- Chest pain during or after sex – stop activity, call 999 if pain does not resolve quickly
- Severe dizziness, fainting, or feeling very unwell – seek same-day medical advice
- Allergic reaction (rash, swelling, difficulty breathing) – call 999
Call 999 or go to A&E in an emergency, or contact NHS 111 for urgent advice.
How Do Vardenafil and Aliskiren Interact?
The interaction between vardenafil and aliskiren is primarily related to their effects on blood pressure. Both medicines can lower blood pressure, and when taken together, this effect may be more pronounced. Vardenafil causes mild vasodilation (widening of blood vessels) as part of its mechanism to improve erectile function, while aliskiren lowers blood pressure by reducing the activity of the renin-angiotensin system.
When these two medicines are combined, there is a potential for an additive blood-pressure-lowering effect. This means you may be more likely to experience symptoms such as dizziness, light-headedness, or fainting, particularly when standing up quickly. However, this interaction is not classified as severe or dangerous for most people, and many men take vardenafil safely alongside blood pressure medicines.
Your prescriber will assess your current blood pressure control, the dose of aliskiren you are taking, and any other medicines or health conditions that might increase your risk of low blood pressure. If your blood pressure is well controlled and you are otherwise healthy, vardenafil is usually considered safe to use. Your prescriber may recommend starting on a lower dose of vardenafil (such as 5 mg) to minimise the risk of side effects.
The Mechanism in Plain English
Think of your blood vessels as a network of flexible tubes. Aliskiren helps keep these tubes relaxed and open by reducing the signals that tell them to tighten. Vardenafil also relaxes blood vessels, particularly in the penis, to allow better blood flow during sexual arousal. When both medicines are working at the same time, the overall relaxation of blood vessels throughout your body can be greater, which may lower your blood pressure more than either medicine would on its own. For most people, this is manageable and does not cause problems, but it is why your prescriber needs to know about all your medicines before approving vardenafil.
What Your Prescriber Will Check Before Approving Vardenafil and Aliskiren Together
When you request vardenafil through an online consultation at Cured Pharmacy, a UK-registered prescriber will review your medical history and current medicines to ensure the treatment is safe for you. If you are taking aliskiren, the prescriber will pay particular attention to your blood pressure control, any symptoms of low blood pressure you may have experienced, and whether you take any other medicines that could interact with vardenafil.
The prescriber will also check for contraindications—conditions or medicines that mean vardenafil should not be used. These include nitrates (such as GTN spray or isosorbide mononitrate), nicorandil, riociguat, and recreational drugs known as 'poppers' (amyl or alkyl nitrites). If you are taking any of these, you must not take vardenafil, as the combination can cause a dangerous drop in blood pressure [5].
Other important factors include recent heart attack or stroke, unstable angina, severe heart failure, very low blood pressure, or a history of sudden vision loss (non-arteritic anterior ischaemic optic neuropathy, or NAION). If you are taking alpha-blockers (such as doxazosin or tamsulosin) for prostate problems, the prescriber will ensure you are stable on that medicine and may start you on the lowest dose of vardenafil. Potent CYP3A4 inhibitors (such as ritonavir, ketoconazole, or clarithromycin) can increase vardenafil levels in the blood; vardenafil is usually avoided or contraindicated with these medicines, so the prescriber will check your full medication list carefully [5].
What to Declare in Your Consultation
Always list every medicine you take, including prescription medicines, over-the-counter treatments, herbal remedies (such as St John's wort), and any recreational substances. Mention your current blood pressure readings if you monitor them at home, and any symptoms such as dizziness, fainting, or chest pain. If you have any heart, liver, or kidney problems, or if you have ever had an allergic reaction to vardenafil or any other medicine, make sure to include this information. Honest and complete answers help the prescriber make the safest decision for you.
At a glance
Practical Advice for Taking Vardenafil and Aliskiren Safely
If your prescriber approves vardenafil while you are taking aliskiren, there are several practical steps you can take to minimise the risk of side effects. First, take vardenafil exactly as prescribed—do not take more than the recommended dose or use it more than once in 24 hours. Start with the lowest effective dose (often 5 mg or 10 mg) and only increase if advised by your prescriber.
Be aware of how you feel when you take vardenafil, especially the first few times. Dizziness or light-headedness is more likely when you stand up quickly, so take your time getting up from sitting or lying down. Avoid drinking large amounts of alcohol, as this can worsen erectile dysfunction and add to the blood-pressure-lowering effect of both medicines. Grapefruit juice can increase the levels of vardenafil in your blood, so it is best to avoid it.
Continue taking aliskiren as prescribed by your GP—do not stop or change the dose without medical advice. If you experience persistent dizziness, fainting, chest pain during sexual activity, or an erection lasting more than four hours (priapism), seek urgent medical help. Regular blood pressure monitoring, either at home or with your GP, can help ensure both medicines are working well together. If you have any concerns or new symptoms, contact your GP or pharmacist for advice.
Other ED Treatments and Alternatives to Vardenafil
If vardenafil is not suitable for you, or if you and your prescriber decide to try a different option, there are several other licensed treatments for erectile dysfunction available in the UK. Sildenafil (generic Viagra) is usually taken about one hour before sex and works in a similar way to vardenafil [3]. Tadalafil (generic Cialis) can be taken on-demand (at least 30 minutes before sex, with effects lasting up to 36 hours) or as a lower daily dose [4]. Avanafil (Spedra) is a newer PDE5 inhibitor that may work as quickly as 15–30 minutes after taking it [6].
All PDE5 inhibitors have similar interactions with blood pressure medicines, including aliskiren, so the same precautions apply. Your prescriber will help you choose the most suitable option based on your lifestyle, how quickly you want the medicine to work, and how long you want the effect to last. Some men prefer the flexibility of tadalafil's longer duration, while others prefer the faster onset of avanafil or the well-established track record of sildenafil.
Non-oral treatments are also available for men who cannot take PDE5 inhibitors. Alprostadil is available as a cream (Vitaros) applied to the tip of the penis or as an injection (Caverject) into the side of the penis; both are prescription-only [7]. Eroxon is a topical gel medical device that can be bought without a prescription. Vacuum erection devices and penile implants are other options that may be discussed with a specialist. If ED is new or worsening, it is important to see your GP, as it can be an early sign of cardiovascular disease or diabetes [1][2].
Choosing the Right Treatment for You
The best ED treatment depends on your individual health, preferences, and lifestyle. During your online consultation at Cured Pharmacy, you can discuss your needs with a UK prescriber who will recommend the most appropriate option. All prescription ED medicines are supplied only after a clinical assessment to ensure they are safe for you. If you have any questions about vardenafil, aliskiren, or any other treatment, our pharmacy team is here to help.
In summary
- Vardenafil and aliskiren can usually be taken together, but both lower blood pressure.
- Your prescriber will check your blood pressure control and may start you on a lower vardenafil dose.
- Report dizziness, fainting, or chest pain to your GP or prescriber promptly.
- Never take vardenafil with nitrates, nicorandil, riociguat, or poppers.
- Declare all medicines, including over-the-counter and herbal products, in your consultation.
Scientific References
- NHS. (n.d.). Erectile dysfunction (impotence). NHS website. https://www.nhs.uk/conditions/erection-problems-erectile-dysfunction/ [accessed 27 October 2026]
- National Institute for Health and Care Excellence. (n.d.). Erectile dysfunction. Clinical Knowledge Summaries. https://cks.nice.org.uk/topics/erectile-dysfunction/ [accessed 27 October 2026]
- Joint Formulary Committee. (n.d.). Sildenafil. British National Formulary. NICE. https://bnf.nice.org.uk/drugs/sildenafil/ [accessed 27 October 2026]
- Joint Formulary Committee. (n.d.). Tadalafil. British National Formulary. NICE. https://bnf.nice.org.uk/drugs/tadalafil/ [accessed 27 October 2026]
- Joint Formulary Committee. (n.d.). Vardenafil. British National Formulary. NICE. https://bnf.nice.org.uk/drugs/vardenafil/ [accessed 27 October 2026]
- Joint Formulary Committee. (n.d.). Avanafil. British National Formulary. NICE. https://bnf.nice.org.uk/drugs/avanafil/ [accessed 27 October 2026]
- Joint Formulary Committee. (n.d.). Alprostadil. British National Formulary. NICE. https://bnf.nice.org.uk/drugs/alprostadil/ [accessed 27 October 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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