Avanafil vs Viagra: How the Newer PDE5 Inhibitor Compares With the Original ED Treatment

• Avanafil and Viagra (sildenafil) are both PDE5 inhibitors licensed for erectile dysfunction, but avanafil is generally faster acting and Viagra has a longer track record of UK use.
• Viagra Connect (sildenafil 50mg) can be bought following a pharmacist consultation with no prescription; avanafil has never been reclassified and remains prescription-only at every strength.
• There is not any sufficient head-to-head evidence to establish that avanafil is more effective than sildenafil overall.
• Genuine UK access to either requires an appropriate clinical assessment and prescription, except where a specific product such as Viagra Connect can be supplied following a pharmacist consultation.

Avanafil and Viagra (sildenafil) are both phosphodiesterase type 5 (PDE5) inhibitors licensed for erectile dysfunction (ED) in adult men, but they are not identical in how they work in practice. Avanafil is generally faster acting and less affected by food, while Viagra has a much longer history of UK use and, in one specific lower-dose form, can be bought without a full prescription; neither has been proven more effective overall than the other.

For men in the UK comparing private, legally compliant treatment options for ED through an online service or pharmacy, the practical differences matter. This page compares avanafil and Viagra directly: onset, duration, food effect, dosing strengths, prescription status, side effects, effectiveness, UK access routes, and whether you may be able to switch between them safely with prescriber advice.

Avanafil and Viagra at a Glance

Both are PDE5 inhibitors in the same class used in the treatment of erectile dysfunction, and both only help after sexual stimulation by increasing blood flow to the penis during sexual arousal rather than creating arousal on their own. Avanafil tends to act faster and is less disrupted by food. Viagra has been available in the UK for far longer and has a specific low-dose version, Viagra Connect, available without a full prescription. Both remain prescription-only medicines in their standard forms, and suitability for either is decided through an individual clinical assessment, not a personal choice between the two.

Both medicines work by supporting nitric oxide signalling in the blood vessels so blood flow can increase as intended; this is how viagra works, even though the underlying process each supports is identical. What differs is how quickly that support kicks in, how forgiving each is around meals, and which route gets you legitimate access in the UK.

What is the Difference Between Avanafil and Viagra?

The core difference is which molecule is doing the work: avanafil in one case, sildenafil citrate (sold as Viagra) in the other. In practical terms, molecular pharmacology shows that avanafil is more selective for the PDE5 enzyme than sildenafil, which helps explain a mechanism-level difference without making it a blanket claim of superiority. Both belong to the same PDE5 inhibitor class and work through the same underlying mechanism, but they differ in how quickly they take effect, and how sensitive they are to food.

Avanafil: The Newer Option

Avanafil is one of the more recently developed PDE5 inhibitors to reach the UK market, sold here under the brand name Spedra. Its licensed dosing information describes use approximately 15 to 30 minutes before sexual activity. It is generally considered one of the faster-acting PDE5 inhibitors, with a rapid onset that may suit people who want more flexibility around timing. It remains prescription-only in the UK at every strength.

Viagra (Sildenafil): The Original

Viagra was the first PDE5 inhibitor to reach the UK market and remains one of the most recognised names in this medicine class. Since 1998, oral sildenafil has had a long-established safety and efficacy profile in erectile dysfunction treatment. Its active ingredient, sildenafil, is also sold under other product names. A specific 50mg version, Viagra Connect, was reclassified from prescription-only to a pharmacy medicine in November 2017, meaning it can be bought following a consultation with a pharmacist rather than needing a full prescription; other sildenafil products remain prescription-only.

A Viagra Connect consultation still involves a pharmacist checking suitability, including relevant health conditions and other medicines being taken, before supply. It is not an unassessed purchase. It is simply a different professional carrying out that assessment compared with the fuller online consultation route used for avanafil and other sildenafil products.

Avanafil vs Viagra: Key Facts Compared

Onset: Which Works Faster?

Avanafil is generally considered one of the faster-acting PDE5 inhibitors, with licensed information describing use approximately 15 to 30 minutes before sexual activity. Viagra's onset can vary depending on factors such as food and individual response often taking effect within around an hour, although food can delay its onset. Neither figure is a guarantee for any specific individual; response varies from person to person.

Duration: How Long Does Each Last?

Both provide an effect lasting several hours rather than extending into the next day, which distinguishes them from a longer-acting PDE5 inhibitor like tadalafil. Avanafil's effect window tends to be on the shorter side within that several-hour range; Viagra's effect gradually tapers off over a broadly similar timeframe. Neither is designed for planning around a single fixed number of hours, since individual response varies.

Food Effect: Does Eating Change How They Work?

Yes, for both, but not equally. It can also have a significant effect on how quickly Viagra starts working, while avanafil tends to have fewer interactions with food in practical use. Avanafil is also affected by food, a high-fat meal can delay how quickly it starts working, but this does not reduce how much of the medicine is ultimately absorbed the way it does with sildenafil. In practical terms, unlike Viagra, avanafil's timing is more forgiving around meals, while Viagra's timing is more sensitive to what and when you have eaten.

Dosing and Strengths

Avanafil is licensed in 50mg, 100mg and 200mg strengths, with 100mg the usual starting point. Sildenafil is also available in a generic version, while avanafil is less widely available as a low-cost generic medication. Viagra (sildenafil) is licensed in 25mg, 50mg and 100mg strengths. In both cases, a prescriber decides the appropriate strength during an individual assessment; neither is a personal choice made independently, and the maximum frequency for either is one dose in any 24-hour period.

Side Effects and Safety Considerations

Both medicines are broken down partly via the CYP3A4 enzyme pathway, meaning certain other medications can affect how each works; a full medicines review with a healthcare provider should cover cardiovascular disease, high blood pressure and any other medications before either is considered.

Common side effects overlap, so both can cause similar side effects such as headache, facial flushing, nasal congestion and mild digestive upset, but reported rates differ.

Both can cause side effects such as headache, facial flushing and nasal congestion, although the frequency of individual effects varies between medicines and studies.

Visual disturbances are recognised adverse effects of sildenafil and are reported less prominently with avanafil.

Neither should be combined with nitrate medicines, due to the risk of a dangerous drop in blood pressure, and extra caution is also needed with alpha blockers or medicines used for chest pain.

Seek urgent medical attention for serious symptoms such as a prolonged painful erection or sudden vision loss. The patient information leaflet supplied with either medicine lists the full, medicine-specific set of possible adverse effects, including rare but serious cardiovascular events.

Both belong to a medicine class that has a mild blood-pressure-lowering effect as part of how it works, which is part of why a clinical assessment covers cardiovascular health and current blood pressure before either is prescribed.

This is not unique to one over the other. It is a class-wide consideration that applies whichever PDE5 inhibitor is being assessed. Although individual side effects and their frequencies can differ between medicines, both require appropriate clinical assessment.

Is One More Effective Than the Other?

Neither can be fairly described as more effective overall. There is not any sufficient head-to-head evidence to establish that avanafil works better than sildenafil, so claims that one is universally more effective are not supported by the evidence. Clinical trials have shown that avanafil is more effective than placebo in improving erectile function, while sildenafil also has established evidence of effectiveness in treating erectile dysfunction. The 2025 EAU guidelines report significant improvements with avanafil compared with placebo, including a 58% success rate versus 28% with placebo. However, this does not establish that avanafil is more effective than sildenafil. The practical differences between the two are more relevant to factors such as onset, food sensitivity and access route than to claiming that one is universally stronger or more effective.

Which One a Prescriber Might Consider

This is not a personal choice made from a comparison table, it is decided through an individual clinical assessment. That said, the practical differences above tend to be the reasons a prescriber discusses one over the other with a patient: how forgiving timing needs to be around meals, how quickly an effect is needed, and any relevant medical history or other medicines being taken.

A few scenarios illustrate why the differences matter practically rather than just on paper. Someone whose plans tend to come together with little notice, or who eats close to when timing matters, may find avanafil's shorter onset window and milder food sensitivity more convenient to plan around. Someone who already has experience with sildenafil, or who prefers a medicine with a long-established UK usage history, may have reasons to continue with Viagra rather than switch. Neither of these is a reason to self-select, they are the kind of context worth raising during a consultation so a prescriber can weigh it alongside your health history.

Switching Between Avanafil and Viagra

If one does not suit, for reasons of timing, tolerability, or simply personal preference, switching to the other is something a prescriber manages as part of an ongoing review rather than something to do independently. This might involve a follow-up consultation to discuss what wasn't working and confirm the new option is appropriate given your health history and any other medicines. Two PDE5 inhibitors should never be taken together or overlapped without a clear gap, regardless of which two are involved.

Common Misconceptions About Avanafil vs Viagra

"Avanafil is automatically better because it is newer." Being newer to the market is not the same as being more effective. There is not any sufficient head-to-head evidence to establish that avanafil is superior.

"Viagra is outdated compared to avanafil." Viagra remains a licensed, actively prescribed medicine with a long safety and usage record; being the older option in the class does not make it obsolete.

"Viagra Connect is a weaker or lesser version of Viagra." It is the same active ingredient at 50mg, reclassified for a specific access route following a pharmacist consultation; it is not a diluted or inferior product.

Buying Avanafil or Viagra in the UK

Both medicines require an appropriate assessment before supply, although Viagra Connect 50mg can be supplied following a pharmacist consultation. A legitimate UK pharmacy will always require the appropriate assessment before dispensing.

Price

Prices are set by individual UK pharmacies and can change. On EveryDayMeds, Spedra (avanafil) is currently listed from £20.69 and Viagra is currently listed from £27.99, both confirmed once the appropriate assessment has been completed rather than shown as a fixed public price; by comparison, generic sildenafil is significantly more affordable than Stendra, with prices starting from about £2.36 per use.

Generic sildenafil may cost substantially less than branded Viagra, depending on the pharmacy and pack size.

Cost should not be the deciding factor between them; clinical suitability, decided through a proper assessment, comes first.

Medical Disclaimer

This page is for general information only and does not constitute medical advice. Avanafil and Viagra (sildenafil) are prescription-only medicines (except where a specific product has been reclassified, such as Viagra Connect), and treatment suitability depends on an individual clinical assessment. Your prescriber will determine the appropriate treatment, dose and monitoring for you. These medicines should only be used under the supervision of an appropriately qualified prescriber. Results vary between individuals. If you have concerns about a side effect, an interaction, or your suitability for treatment, speak to a healthcare provider, pharmacist, prescriber or your GP, and seek urgent medical attention if you develop serious symptoms.