Avanafil Side Effects: How Long Do They Last?

Avanafil Side Effects: How Long Do They Last?

Published: 17 October 2026

If you're wondering about avanafil side effects how long do they last, the good news is that most common side effects—such as headache, flushing, or nasal congestion—typically resolve within a few hours as the medicine leaves your system. Avanafil (sold as Spedra in the UK) is a fast-acting PDE5 inhibitor used to treat erectile dysfunction, and while side effects can occur, they are usually mild and short-lived. Understanding what to expect and how to manage any discomfort can help you use avanafil confidently and safely.

Why does avanafil cause side effects?

Avanafil works by blocking an enzyme called phosphodiesterase type 5 (PDE5), which increases blood flow to the penis during sexual stimulation [6]. However, PDE5 is also present in other parts of the body, including blood vessels in the head, face, and nasal passages. When avanafil inhibits PDE5 in these areas, it can cause blood vessels to widen, leading to common side effects such as headache, facial flushing, and a stuffy or runny nose [6].

These effects are a direct result of how the medicine works, rather than an allergic reaction or sign of harm. Most people tolerate avanafil well, and side effects tend to be dose-related—meaning they may be more noticeable at higher doses (such as 200 mg) than at lower ones (50 mg or 100 mg) [11]. Because avanafil is rapidly absorbed and eliminated from the body, side effects usually fade as the drug concentration decreases.

It's also worth noting that individual responses vary. Factors such as your overall health, other medications you take, and whether you've eaten a large meal can influence both the effectiveness of avanafil and the likelihood of side effects. If you experience side effects that concern you, your prescriber can adjust your dose or suggest an alternative treatment.

How long do avanafil side effects typically last?

Most side effects from avanafil are short-lived and resolve within 2 to 6 hours after taking the tablet [6]. Avanafil has a half-life of about 3 to 5 hours, meaning that half the dose is cleared from your bloodstream in that time. As the medicine is metabolised and excreted, the widening of blood vessels in areas outside the penis gradually reverses, and symptoms such as headache, flushing, and nasal congestion typically subside.

Headache is one of the most commonly reported side effects, and for most men it is mild and fades within a few hours without treatment [11]. Facial flushing—a warm, red sensation in the face and neck—also tends to disappear as avanafil levels drop. Nasal congestion or a runny nose may persist slightly longer but usually clears by the next morning. Back pain or muscle aches, which are less common with avanafil than with some other PDE5 inhibitors, also resolve within hours to a day [6].

If you find that side effects last longer than 12 hours or become more severe with repeated use, it's important to discuss this with your prescriber. Persistent or worsening symptoms may indicate that avanafil is not the best option for you, and alternatives such as sildenafil, tadalafil, or vardenafil may be more suitable.

When do avanafil side effects start?

Avanafil is one of the fastest-acting PDE5 inhibitors, with effects typically felt within 15 to 30 minutes of taking the tablet [6]. Side effects, if they occur, usually begin around the same time—often within the first hour. You may notice a warm flush in your face or a mild headache shortly after the medicine starts working. These symptoms coincide with peak blood levels of avanafil, which occur about 30 to 45 minutes after ingestion [11]. As the drug is absorbed and begins to work, the same mechanism that improves blood flow to the penis can also affect blood vessels elsewhere, leading to the characteristic side effects.

Self-care tips to manage avanafil side effects

If you experience mild side effects from avanafil, there are several practical steps you can take to ease discomfort. For headache, drinking plenty of water before and after taking avanafil can help, as dehydration may worsen headaches. Over-the-counter painkillers such as paracetamol or ibuprofen are generally safe to use alongside avanafil and can provide relief [6]. Avoid taking avanafil with heavy or high-fat meals, as this can delay absorption and may prolong the time side effects are felt.

For facial flushing, staying in a cool environment and avoiding hot drinks or spicy foods around the time you take avanafil may reduce the intensity of the flush. If nasal congestion is bothersome, a saline nasal spray or steam inhalation can help clear your airways without interfering with the medicine. Avoid using decongestant nasal sprays for more than a few days, as prolonged use can cause rebound congestion.

Limiting alcohol intake is also important. Heavy drinking can worsen erectile dysfunction and increase the risk of dizziness or low blood pressure when combined with avanafil [6]. Stick to no more than one or two units of alcohol if you plan to take avanafil. If you smoke, consider cutting down or quitting, as smoking damages blood vessels and can reduce the effectiveness of ED treatments. Finally, if side effects are troublesome, speak to your prescriber about trying a lower dose—many men find that 50 mg or 100 mg avanafil provides effective results with fewer side effects than the 200 mg dose.

How common are side effects with avanafil?

Clinical trials show that avanafil is generally well tolerated, with most side effects being mild to moderate in severity [11]. Headache is the most frequently reported side effect, affecting around 10–15% of men taking avanafil. Flushing occurs in approximately 3–10% of users, while nasal congestion affects about 2–5% [6]. Back pain and dizziness are less common, each reported by fewer than 3% of men in trials.

Serious side effects are rare. Priapism—a painful erection lasting more than 4 hours—occurs in fewer than 1 in 1,000 men taking PDE5 inhibitors, but it requires urgent medical attention to prevent permanent damage [6]. Sudden vision or hearing loss is also very rare but must be treated as a medical emergency. Allergic reactions to avanafil are uncommon; symptoms such as rash, itching, swelling of the face or throat, or difficulty breathing require immediate help.

It's reassuring to know that most men who experience side effects find them manageable and short-lived. In clinical studies, discontinuation rates due to side effects were low, suggesting that avanafil is a practical and effective option for many men with erectile dysfunction [11]. If you have concerns about side effects, your prescriber can review your medical history and current medications to ensure avanafil is safe and appropriate for you.

Are side effects worse with higher doses?

Yes, side effects tend to be more common and more noticeable at higher doses of avanafil [6]. For example, men taking 200 mg are more likely to report headache or flushing than those taking 50 mg or 100 mg. This dose-response relationship is typical of PDE5 inhibitors and reflects the greater degree of enzyme inhibition at higher doses. If you find that 200 mg causes bothersome side effects, your prescriber may recommend stepping down to 100 mg, which often provides effective results with improved tolerability.

When should you seek medical help for avanafil side effects?

While most side effects from avanafil are mild and resolve on their own, certain symptoms require urgent medical attention. If you develop an erection that lasts longer than 4 hours (priapism), you must go to A&E or call 999 immediately [6]. Priapism can cause permanent damage to the penis if not treated promptly. Do not wait for the erection to subside on its own.

Sudden loss of vision in one or both eyes, or sudden hearing loss or ringing in the ears, are rare but serious side effects that require immediate medical assessment [6]. These symptoms may indicate a condition called non-arteritic anterior ischaemic optic neuropathy (NAION) or sudden sensorineural hearing loss, both of which need urgent investigation. If you experience chest pain, severe dizziness, or fainting during or after sexual activity, stop and seek medical help straight away, as these may be signs of a cardiovascular problem.

Allergic reactions to avanafil are uncommon but can be serious. Symptoms such as swelling of the face, lips, tongue, or throat, difficulty breathing, or a widespread rash require emergency treatment. If you have any concerns about side effects that do not settle within 12 hours, or if symptoms worsen with repeated use, contact your GP or pharmacist for advice. Never take more than one dose of avanafil in 24 hours, and do not combine it with other PDE5 inhibitors or medicines containing nitrates, as this can cause a dangerous drop in blood pressure [6].

Alternatives if avanafil side effects persist

If you find that avanafil side effects how long do they last is a concern because symptoms are too bothersome or do not settle quickly enough, there are several alternative treatments for erectile dysfunction available through Cured Pharmacy. Sildenafil (generic Viagra) is a well-established PDE5 inhibitor that works in about an hour and may cause fewer headaches in some men, though individual responses vary [3]. Tadalafil (generic Cialis) has a longer duration of action—up to 36 hours—and can be taken as a lower daily dose (2.5 mg or 5 mg), which may reduce the intensity of side effects compared to on-demand dosing [4].

Vardenafil (generic Levitra) is another option that works similarly to avanafil but may be better tolerated by some men [5]. Each PDE5 inhibitor has a slightly different side-effect profile, and what causes discomfort with one medicine may not occur with another. Your prescriber can help you find the best option based on your medical history, lifestyle, and preferences. All prescription ED treatments at Cured Pharmacy are supplied following an online consultation reviewed by a UK-registered prescriber, ensuring that the medicine is safe and suitable for you.

If oral PDE5 inhibitors are not suitable or effective, other treatments such as Vitaros (alprostadil cream) or Caverject (alprostadil injection) may be considered [7]. These are prescription-only and work by a different mechanism, so they may be an option if you cannot tolerate PDE5 inhibitors. Eroxon, a topical gel medical device, is available without prescription and may be worth discussing with your pharmacist. Remember, it's important to see your GP if you have new or worsening erectile dysfunction, as it can be an early sign of underlying health conditions such as diabetes or heart disease [1].

Can you switch between ED medicines?

Yes, you can switch between different PDE5 inhibitors if one does not suit you, but you must do so under the guidance of a prescriber [2]. Never take two different ED medicines on the same day, as this increases the risk of serious side effects, including a dangerous drop in blood pressure. Your prescriber will review your response to avanafil and any side effects you've experienced before recommending an alternative. Many men find that trying a different PDE5 inhibitor or adjusting the dose resolves tolerability issues while maintaining effective treatment for erectile dysfunction.

Scientific References

1. NHS. (n.d.). Erectile dysfunction (impotence). NHS website. https://www.nhs.uk/conditions/erection-problems-erectile-dysfunction/ [accessed 17 October 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 17 October 2026]
3. Joint Formulary Committee. (n.d.). Sildenafil. British National Formulary. NICE. https://bnf.nice.org.uk/drugs/sildenafil/ [accessed 17 October 2026]
4. Joint Formulary Committee. (n.d.). Tadalafil. British National Formulary. NICE. https://bnf.nice.org.uk/drugs/tadalafil/ [accessed 17 October 2026]
5. Joint Formulary Committee. (n.d.). Vardenafil. British National Formulary. NICE. https://bnf.nice.org.uk/drugs/vardenafil/ [accessed 17 October 2026]
6. Joint Formulary Committee. (n.d.). Avanafil. British National Formulary. NICE. https://bnf.nice.org.uk/drugs/avanafil/ [accessed 17 October 2026]
7. Joint Formulary Committee. (n.d.). Alprostadil. British National Formulary. NICE. https://bnf.nice.org.uk/drugs/alprostadil/ [accessed 17 October 2026]
8. National Institute for Health and Care Excellence. (2014). Erectile dysfunction: avanafil (ESNM45). https://www.nice.org.uk/advice/esnm45 [accessed 17 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.