Stendra (Avanafil) – Patient Guide (UK)

Stendra is a medicine used to treat erectile dysfunction (ED) in adult men. The active ingredient is avanafil. This guide explains how Stendra works, how to take it, common safety points, and what to expect in terms of timing and interactions—tailored for people in the United Kingdom.

Note: This information is for general guidance. Individual suitability can vary depending on health conditions and other medicines.

1. Basic product information

• What it’s for: Treatment of erectile dysfunction (ED).
• How it works: Improves blood flow to the penis when sexually stimulated.
• How it’s taken: By mouth, usually as an “as needed” tablet before sex.

2. Mechanism of action (how Stendra works)

Stendra contains avanafil, which belongs to a class called PDE5 inhibitors (phosphodiesterase type 5 inhibitors). In erectile function, nitric oxide (NO) is released during sexual stimulation. NO increases levels of cGMP, which helps relax the muscles in penile blood vessels and increases blood flow.

PDE5 breaks down cGMP. Avanafil inhibits PDE5, allowing cGMP to work for longer. The result is improved ability to achieve and maintain an erection that is suitable for sexual activity.

• Important: Stendra does not cause an automatic erection. It works only with sexual stimulation.
• Effect depends on arousal: You typically still need sufficient sexual stimulation to get the desired effect.

3. Pharmacokinetics (how the body handles avanafil)

Pharmacokinetics describes absorption, distribution, metabolism, and elimination.

• Absorption: Avanafil is absorbed after oral dosing and reaches peak levels in the bloodstream typically within about 30–60 minutes for many people.
• Onset: Effects may begin within as little as 15–30 minutes for some men, although individual response varies.
• Duration: The effect can last several hours; however, the exact duration differs depending on dose, timing, and individual factors.
• Metabolism: Avanafil is mainly broken down by the liver enzyme system, particularly CYP3A4.
• Elimination: The metabolites are excreted primarily through bile/feces and to a lesser extent through urine.

Because avanafil is metabolised by CYP3A4, medicines that strongly affect this pathway can significantly change avanafil levels in the body (see interaction section below).

4. Typical use and timing

Stendra is typically used on an “as needed” basis before sexual activity.

When to take it

• Many men take Stendra approximately 15–30 minutes before sex.
• For some, taking it earlier (around 30–60 minutes before) may produce more predictable results.

How often to take it

• Follow the dosing instructions provided by your clinician or product guidance.
• In general ED treatment, PDE5 inhibitors are usually taken no more than once per day.

If it doesn’t work the first time: Timing, food, alcohol, arousal, and other medications can affect results. It may take a few tries to find what timing works best for you.

5. Indications (what it is used for)

Stendra is indicated for the treatment of erectile dysfunction in adult men, meaning the persistent inability to achieve or maintain an erection sufficient for satisfactory sexual performance.

It is not intended for use in women or children.

6. Dosing (usual starting approach and practical guidance)

Below is typical dosing information commonly used for ED medicines. Exact dosing for you may differ depending on your health, other medicines, and tolerability.

Usual starting dose

• Common starting doses for avanafil are often 100 mg or 200 mg based on clinical decision-making.

Adjusting dose

• If the medicine is not effective or side effects occur, the dose may be adjusted.
• Some people require special caution due to kidney/liver impairment or interacting medicines.

Missed dose

• Because Stendra is taken before sex, there is generally no concept of a “missed daily dose.” Take it only when you plan sexual activity, within the recommended timing.

Do not exceed the recommended maximum daily dose. Taking more than advised does not generally improve effectiveness and increases the risk of side effects.

7. Food interactions (what you should know)

Food can affect how quickly Stendra begins to work. Taking avanafil with a heavy or high-fat meal may delay absorption and reduce or delay the onset of effect.

• Tip: If you want a quicker effect, consider taking it on a relatively lighter meal or when your meal is not overly high in fat.
• Timing adjustment: If you’ve eaten a large meal, you may need to take the tablet earlier than usual.

Stendra can be taken with or without food, but your experience may be more predictable when the timing relative to meals is consistent.

8. Alcohol and medicine interactions

Alcohol (effects and safety)

Moderate alcohol may still be used by some people, but alcohol can make ED harder to treat by affecting sexual performance and increasing side effects such as dizziness and headache.

• Practical advice: Try to keep alcohol moderate.
• Be cautious if you feel light-headed: Avoid driving or hazardous activities if you feel dizzy.

Medicines you must not combine (absolute or near-absolute cautions)

The most important interaction involves nitrates and nitric oxide donors (often used for chest pain/angina), which can cause a dangerous drop in blood pressure when combined with PDE5 inhibitors.

• Do not take Stendra with nitrates such as glyceryl trinitrate (GTN), isosorbide mononitrate, or isosorbide dinitrate.
• Do not use “poppers” (alkyl nitrites) with Stendra.

Seek urgent medical advice if you have chest pain and have taken Stendra recently—do not self-treat with nitrates.

Other important interactions

Because avanafil is metabolised by CYP3A4, medicines that inhibit or induce CYP3A4 can significantly affect avanafil levels.

• CYP3A4 inhibitors (may increase avanafil levels): Examples include certain antifungals (e.g., ketoconazole, itraconazole), some antibiotics (e.g., clarithromycin), and some HIV medicines (e.g., ritonavir-containing regimens). These combinations may increase risk of side effects and may require dose limits or avoidance.
• CYP3A4 inducers (may reduce effectiveness): Examples include rifampicin and certain seizure medicines (e.g., carbamazepine, phenytoin, phenobarbital). These can reduce avanafil’s effect.

Blood pressure medicines and other ED medicines

• Alpha-blockers (used for prostate enlargement or high blood pressure) can lower blood pressure; combining may require careful timing and dose adjustments.
• Other PDE5 inhibitors should not be taken together.

Medicines that affect erections indirectly

Some antidepressants, antipsychotics, and other medicines can contribute to ED by affecting libido, hormone balance, or sexual function. Stendra may help erections, but the underlying cause may need review.

9. Safety profile (common side effects and when to seek help)

Most men tolerate Stendra well. However, like all medicines, it can cause side effects.

Common side effects

• Headache
• Flushing (warmth/redness)
• Facial flushing
• Blocked or runny nose
• Dizziness
• Indigestion or mild stomach discomfort
• Nausea

Less common but serious warnings

Stop using Stendra and seek urgent medical advice if you experience:

• Chest pain (especially if you have taken Stendra). Do not take nitrates unless directed in an emergency by medical professionals.
• Severe dizziness or fainting
• Sudden vision changes (including loss of vision)
• Sudden hearing changes
• Priapism (an erection lasting 4 hours or more)—this requires emergency care

Special caution groups

Extra caution may be needed if you have:

• Heart conditions or a history of serious cardiac events
• Low blood pressure (hypotension)
• Severe liver impairment
• Severe kidney impairment
• Certain retinal disorders or a history of non-arteritic anterior ischaemic optic neuropathy

If any of the above applies, it’s especially important to discuss the safest option and appropriate dosing.

10. Practical use tips for better results

• Plan timing: Take Stendra about 15–30 minutes before sex; adjust if you’re eating a large meal.
• Include arousal: The medication works with sexual stimulation; allow time for natural arousal.
• Stay consistent: Keep meal size and timing similar across attempts so you can tell what works.
• Limit alcohol: Too much alcohol can reduce effectiveness and worsen side effects.
• Don’t double up: Avoid taking extra tablets to “boost” effect.
• Be aware of dizziness: If you feel light-headed, sit or lie down and avoid driving.
• Check interactions: Review all current medicines, including “as needed” products and herbal supplements.

Important: If you experience side effects, avoid attempting sex again until you feel well and consider whether a dose adjustment or alternative treatment is needed.

11. Alternative options for erectile dysfunction

There are several ways to manage ED. The best option depends on your medical history, preference, and whether ED is related to lifestyle, vascular health, hormones, or medication side effects.

Alternative medicine options

• Other PDE5 inhibitors: such as sildenafil, tadalafil, and vardenafil. These differ in onset and duration, and may suit different schedules.
• Urologist-led options: Some men may be considered for other ED treatments depending on cause and response.

Non-medicine options

• Lifestyle changes: improving cardiovascular health, weight management, regular exercise, stopping smoking, and reducing heavy alcohol intake.
• Psychological support: stress, performance anxiety, and relationship issues can contribute to ED.
• Devices or therapies: vacuum erection devices or counselling approaches may help.

It can be helpful to discuss ED as part of overall health because ED can sometimes be an early sign of vascular disease.

12. Market and legal context in the UK (availability and guidance)

In the United Kingdom, medicines for erectile dysfunction are regulated under UK medicines legislation and must be supplied through appropriate channels. Online pharmacies offering prescription and pharmacy services operate under UK rules and safety standards, including checks to help ensure correct supply and safe use.

Patients are encouraged to:

• Use reputable UK-licensed pharmacy services.
• Ensure any ED medicine is obtained from a legitimate source.
• Disclose all relevant medical conditions and medicines to support safe use.

Because online availability can change, the exact brands, tablet strengths, and delivery times may vary by supplier.

Recent guidance (general safety emphasis)

Recent UK and international emphasis for PDE5 inhibitors focuses on safe prescribing/supply, careful interaction screening (especially nitrates and strong CYP3A4 inhibitors), and timely escalation for serious adverse effects. If you have cardiovascular risk factors or take complex medication regimens, it is important to receive personalised advice.

13. Delivery and availability (online pharmacy expectations)

Availability of Stendra and specific tablet strengths can vary by stock levels. When ordering online from a UK pharmacy service:

• Check product strength: Confirm whether you are purchasing 100 mg, 150 mg, or 200 mg.
• Packaging and instructions: You should receive patient information and directions for use with the product.
• Delivery times: Delivery time depends on processing time, courier schedules, and where you live within the UK.
• Temperature/security: Medicines are generally shipped in appropriate packaging; follow any storage instructions provided.

If you need the medicine urgently, check the pharmacy’s dispatch and delivery options at checkout.

14. Frequently asked questions (FAQ)

How quickly does Stendra work?

Many people notice effects within 15–30 minutes, though for others it may take longer. Heavy or high-fat meals may delay onset.

How long does the effect last?

Effect duration varies by person. In general, PDE5 inhibitors provide a window of effectiveness lasting a number of hours, but the “best time” for erection is often within the first part of that window.

Can I take Stendra every day?

ED medicines are usually taken only when needed, not necessarily daily. Do not exceed the recommended daily maximum dose as advised by the pharmacy/clinician or product information.

Can I take Stendra with food?

Yes. However, a heavy or high-fat meal may delay absorption and reduce or postpone the onset of effect. For quicker action, consider a lighter meal or adjust the timing.

Is it safe to drink alcohol with Stendra?

Some alcohol may be compatible for some people, but alcohol can worsen ED and increase side effects such as dizziness or flushing. Keep alcohol moderate and be cautious if you feel light-headed.

What medicines should I avoid?

The most important avoidance is nitrates (and “poppers” containing nitrites). Also use caution with strong CYP3A4 inhibitors and alpha-blockers. Always check all your medicines for interactions.

What if I get side effects like headache or flushing?

Headache, flushing, and nasal congestion are common. Mild side effects often settle as the medicine wears off. If side effects are severe, persistent, or concerning, stop and seek medical advice.

What should I do if the erection lasts too long?

If you have an erection lasting 4 hours or more, seek emergency medical care. Priapism can cause tissue damage and requires prompt treatment.

Will Stendra work if I have diabetes or high blood pressure?

Many men with diabetes or hypertension can use PDE5 inhibitors, but safety depends on overall health and medications. People with significant cardiovascular disease or blood pressure concerns may need extra evaluation.

Is Stendra the only option?

No. Other PDE5 inhibitors (e.g., sildenafil or tadalafil) and non-medicine approaches may suit different needs. If Stendra doesn’t work or isn’t tolerated, an alternative may be considered.

Can I use Stendra if I take treatment for prostate symptoms?

Some prostate medicines are alpha-blockers. Combining them can affect blood pressure, requiring careful dose selection and timing. It’s important to check the specific medication and discuss suitability.

Summary

Stendra (avanafil) is an ED medicine in the PDE5 inhibitor group, designed to help you achieve and maintain an erection when you are sexually stimulated. It is typically taken 15–30 minutes before sex, with effects that can be influenced by meal size, alcohol, and interacting medicines—especially nitrates and strong CYP3A4 inhibitors.

If you’re unsure whether Stendra is suitable for you, or if you have heart disease, low blood pressure, liver/kidney issues, or take multiple medicines, it’s best to seek advice from a healthcare professional or a pharmacist before use.