Vardenafil Maximum Dose: Safe Limits Explained

What Is the Vardenafil Maximum Dose?

Published: 9 November 2026

The vardenafil maximum dose licensed in the UK is 20mg, taken as a single tablet once per day [5]. Vardenafil, the active ingredient in Levitra, is a PDE5 inhibitor used to treat erectile dysfunction (ED) and should be taken approximately 25 to 60 minutes before sexual activity [5]. Your prescriber will usually start you on a lower dose (typically 10mg) and adjust based on how well it works and any side effects you experience, but you should never exceed 20mg in a 24-hour period.

Understanding Vardenafil Maximum Dose Limits

Vardenafil is available in three strengths in the UK: 5mg, 10mg, and 20mg [5]. The standard starting dose for most men is 10mg, taken about 25 to 60 minutes before sexual activity [5]. If this dose is effective and well-tolerated, your prescriber may continue it; if it does not work well enough, the dose can be increased to the maximum of 20mg [5]. Conversely, if you experience side effects, the dose may be reduced to 5mg.

The 20mg maximum applies to all men taking vardenafil, regardless of age or other factors, and you must not take more than one dose in any 24-hour period [5]. Taking more than the recommended maximum dose does not improve effectiveness but significantly increases the risk of side effects such as headache, flushing, dizziness, and potentially dangerous drops in blood pressure [5]. Vardenafil works only in the presence of sexual stimulation, so higher doses will not create an erection on their own.

It is important to understand that the maximum dose is not necessarily the best dose for everyone. Many men find that 10mg or even 5mg is sufficient and causes fewer side effects [5]. Your prescriber will tailor the dose to your individual needs, taking into account your overall health, other medications, and how you respond to treatment. Never adjust your dose without consulting your prescriber or pharmacist first.

When the Vardenafil Maximum Dose Must Be Reduced

Certain medical conditions and medications require a lower maximum dose of vardenafil to ensure safety. If you have moderate liver impairment, the maximum dose is reduced to 10mg, and vardenafil is not recommended at all if you have severe liver disease [5]. Similarly, men over 65 years of age may be started on a lower dose (5mg) because the body processes vardenafil more slowly with age, though the maximum can still be 20mg if tolerated [5].

Drug interactions are a critical reason for dose adjustments. If you are taking certain medicines that slow the breakdown of vardenafil in the body—particularly potent CYP3A4 inhibitors such as ritonavir, cobicistat (found in some HIV treatments), ketoconazole, itraconazole, or clarithromycin—vardenafil may be contraindicated or the dose must be significantly reduced [5]. Your prescriber will check the specific interaction and may advise avoiding vardenafil altogether or limiting you to a much lower dose.

Men taking alpha-blockers for an enlarged prostate or high blood pressure (such as doxazosin, tamsulosin, or alfuzosin) should be stable on their alpha-blocker therapy before starting vardenafil, and the lowest effective dose of vardenafil should be used to minimise the risk of dizziness or fainting from low blood pressure [5]. Always declare all your current medications during your consultation, as your prescriber must review every medicine to ensure vardenafil is safe for you.

Liver and Kidney Function

Liver function has a significant impact on how vardenafil is processed. The liver breaks down vardenafil, so if your liver is not working properly, the medicine stays in your body longer and at higher levels, increasing the risk of side effects [5]. For moderate liver impairment (Child-Pugh B), the maximum dose is 10mg, and for severe impairment (Child-Pugh C), vardenafil should not be used [5]. Kidney function, on the other hand, does not usually require dose adjustment for vardenafil, as the kidneys play a smaller role in clearing the drug [5]. However, your prescriber will still assess your overall health, including kidney function, as part of the consultation to ensure vardenafil is appropriate and safe for you.

How Vardenafil Compares to Other ED Medicines

Vardenafil is one of four PDE5 inhibitors licensed for ED in the UK, alongside sildenafil (Viagra), tadalafil (Cialis), and avanafil (Spedra) [3][4][5][6]. Each has a different maximum dose and duration of action. Sildenafil has a maximum dose of 100mg and lasts about 4 to 6 hours [3]. Tadalafil's on-demand maximum is 20mg, but its effect can last up to 36 hours, earning it the nickname 'the weekend pill' [4]. Avanafil's maximum is 200mg, and it is the fastest-acting, working in as little as 15 to 30 minutes [6].

Vardenafil's maximum dose of 20mg sits in the middle of this range, and it typically works within 25 to 60 minutes, with effects lasting around 4 to 5 hours [5]. Some men find vardenafil effective when other PDE5 inhibitors have not worked as well, though all four medicines work in a similar way by increasing blood flow to the penis during sexual stimulation [2]. The choice between them often comes down to how quickly you need the medicine to work, how long you want the effect to last, side effects, and personal preference.

All PDE5 inhibitors share the same serious contraindications: they must never be taken with nitrates (such as GTN spray or isosorbide mononitrate), nicorandil, riociguat, or recreational drugs called 'poppers', as this combination can cause a dangerous drop in blood pressure [3][4][5][6]. They also share common side effects such as headache, flushing, nasal congestion, and indigestion [5]. Your prescriber will help you choose the most suitable option based on your medical history and lifestyle.

What Happens If You Exceed the Maximum Dose?

Taking more than the vardenafil maximum dose of 20mg in a 24-hour period does not make the medicine work better, but it does significantly increase the risk of side effects [5]. Common side effects such as headache, facial flushing, dizziness, nasal congestion, and indigestion become more likely and more severe at higher doses [5]. More seriously, exceeding the maximum dose raises the risk of a dangerous drop in blood pressure, especially if you are also taking other medicines that lower blood pressure or if you drink alcohol [5].

Rare but serious side effects also become more likely with overdose. These include priapism (a painful erection lasting more than four hours, which requires emergency treatment to prevent permanent damage), sudden loss of vision in one or both eyes (a condition called non-arteritic anterior ischaemic optic neuropathy, or NAION), and sudden hearing loss or ringing in the ears [5]. If you experience any of these symptoms, stop taking vardenafil and seek urgent medical help immediately.

If you accidentally take more than 20mg of vardenafil, contact your GP, pharmacist, or NHS 111 for advice, even if you feel well. Do not take another dose within 24 hours of the first. If you develop chest pain, severe dizziness, fainting, or an erection that will not go down, call 999 or go to A&E straight away. Always store vardenafil safely out of reach of children and others, and never share your prescription with anyone else, as it may not be safe for them.

Emergency Symptoms to Watch For

Certain symptoms after taking vardenafil require immediate medical attention. An erection lasting longer than four hours (priapism) is a medical emergency because prolonged lack of blood flow can permanently damage the tissue of the penis [5]. Sudden loss of vision in one or both eyes, or sudden decrease or loss of hearing (sometimes with ringing in the ears or dizziness), are also emergencies and may indicate serious complications [5]. Chest pain during or after sexual activity should never be ignored, as it could indicate a heart problem; stop sexual activity, do not take another dose, and seek urgent help [5]. If you experience severe dizziness, fainting, or feel very unwell after taking vardenafil, especially if you have also taken other medicines or alcohol, call 999 or go to A&E.

Starting Vardenafil: What to Expect

When you first start vardenafil, your prescriber will usually recommend the 10mg dose to assess how well you tolerate it and how effective it is [5]. You should take the tablet approximately 25 to 60 minutes before you plan to have sex, with or without food, though a high-fat meal may delay how quickly it works [5]. Vardenafil will only help you get an erection if you are sexually aroused; it does not increase sexual desire or cause an automatic erection.

After your first few doses, your prescriber may adjust the dose based on your experience. If 10mg works well and you have no troublesome side effects, you may continue on that dose. If it is not quite effective enough, the dose can be increased to the maximum of 20mg [5]. If you experience side effects such as headache or flushing, the dose may be reduced to 5mg. It is important to give vardenafil a fair trial—some men find it works better after a few attempts as they become more relaxed and confident.

Remember that vardenafil is not a cure for ED; it treats the symptoms by helping you achieve and maintain an erection sufficient for sexual activity [2]. ED can be an early warning sign of underlying health problems such as heart disease, diabetes, or high blood pressure, so if you are experiencing ED for the first time, it is important to see your GP for a full assessment [1][2]. Lifestyle changes such as losing weight, stopping smoking, reducing alcohol, and increasing physical activity can also improve ED and overall health [1][2].

Getting Vardenafil Through Cured Pharmacy

Vardenafil is a prescription-only medicine in the UK, which means you need a consultation with a qualified prescriber before it can be supplied [5]. At Cured Pharmacy, a GPhC-registered online pharmacy (GPhC 9012511), you can complete a confidential online consultation that is reviewed by a UK-registered prescriber. The prescriber will check your medical history, current medications, and overall health to ensure vardenafil is safe and appropriate for you, and will determine the correct starting dose.

Cured Pharmacy offers vardenafil (generic Levitra) at £16.95 for a pack, or £13.56 for first orders using the code Ednew. This is the same active ingredient as branded Levitra but at a lower cost. If vardenafil is not suitable for you, the prescriber may recommend an alternative PDE5 inhibitor such as sildenafil (from £0.45, or £0.36 with code Ednew), tadalafil (from £7.95, or £6.36 with code Ednew), or avanafil (Spedra, £20.95, or £16.76 with code Ednew). All consultations are confidential, and medicines are delivered discreetly to your door.

During the consultation, you will be asked about any other medicines you take, including over-the-counter products and herbal supplements, as some can interact with vardenafil. You will also be asked about your heart health, blood pressure, liver and kidney function, and any history of eye or blood disorders. This information is essential to ensure vardenafil is safe for you and to determine the correct dose. If you have any questions or concerns, the pharmacy team is available to help, and you can contact your GP at any time for further advice.

Why Choose an Online Consultation?

Online consultations for ED treatment offer privacy, convenience, and access to the same high standards of care as a face-to-face GP appointment. Many men find it easier to discuss sensitive issues like ED through a confidential online form, and you can complete the consultation at a time that suits you. Every consultation at Cured Pharmacy is reviewed by a UK-registered prescriber who is trained to assess ED and ensure the treatment is safe and appropriate for you. If the prescriber has any concerns or needs more information, they may contact you or suggest you see your GP for further tests. Online pharmacies like Cured Pharmacy are regulated by the General Pharmaceutical Council (GPhC) and must meet the same strict standards as high-street pharmacies, so you can be confident you are receiving safe, legal, and effective treatment.

Scientific References

1. NHS. (n.d.). Erectile dysfunction (impotence). NHS website. https://www.nhs.uk/conditions/erection-problems-erectile-dysfunction/ [accessed 9 November 2026]
2. National Institute for Health and Care Excellence. (n.d.). Erectile dysfunction. Clinical Knowledge Summaries. https://cks.nice.org.uk/topics/erectile-dysfunction/ [accessed 9 November 2026]
3. Joint Formulary Committee. (n.d.). Sildenafil. British National Formulary. NICE. https://bnf.nice.org.uk/drugs/sildenafil/ [accessed 9 November 2026]
4. Joint Formulary Committee. (n.d.). Tadalafil. British National Formulary. NICE. https://bnf.nice.org.uk/drugs/tadalafil/ [accessed 9 November 2026]
5. Joint Formulary Committee. (n.d.). Vardenafil. British National Formulary. NICE. https://bnf.nice.org.uk/drugs/vardenafil/ [accessed 9 November 2026]
6. Joint Formulary Committee. (n.d.). Avanafil. British National Formulary. NICE. https://bnf.nice.org.uk/drugs/avanafil/ [accessed 9 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.