Erectile Dysfunction · Medication Guide
Avanafil in Thailand
What avanafil is, how fast it works, its side effects, and how men in Bangkok can access it legally. Avanafil is the newest PDE5 inhibitor for erectile dysfunction. Reviewed by a licensed physician at a MOPH-registered men's health clinic.
- Works in as little as 15 minutes
- Prescription only · not sold over the counter
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Medically reviewed by Dr. Noppon Arunkajohnsak (Win)
Menscape Clinic
Last reviewed
11 July 2026
~15 min
Onset as fast as
can be dosed 15–30 minutes before
~6 h
Effective window
shorter than tadalafil's longer window
2012
Newest PDE5 inhibitor
US FDA approval; EU followed in 2013
57%
Successful attempts
on 200 mg versus 27% on placebo
Key takeaways
Avanafil is a prescription PDE5 inhibitor for erectile dysfunction, and the newest medicine in that class, designed to act fast and selectively.
It can work in as little as 15–30 minutes and lasts around 6 hours, a shorter and more on-demand window than tadalafil.
In Thailand it is prescription only. Unlike sildenafil and tadalafil, it is not widely registered or stocked here, so Menscape orders it per patient after a consultation.
It must never be combined with nitrate heart medicines, and a doctor should check your heart health before prescribing any ED tablet.
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What avanafil is & how it works
Avanafil is an oral prescription medicine used to treat erectile dysfunction (ED), the medical condition where a man cannot reliably get or keep an erection firm enough for sex. It belongs to the same family as sildenafil and tadalafil, the PDE5 inhibitors, and is the most recently approved of them.
An erection is a blood-flow event. When a man is sexually aroused, nerves in the penis release nitric oxide, which raises a signalling molecule called cGMP. cGMP relaxes the smooth muscle in the blood vessels so blood flows in and the penis becomes firm. An enzyme called PDE5 breaks cGMP down again, which is part of how an erection normally subsides. Avanafil blocks PDE5, so cGMP stays higher for longer and a natural erection can be maintained.
Two things follow from this. Avanafil only works with sexual stimulation; it does not create arousal or desire on its own, and it is not a performance booster. And it treats the symptom, not the cause, so a proper assessment of why the ED is happening matters as much as the tablet itself. What sets avanafil apart within the class is its speed and its high selectivity for PDE5, not greater overall potency.
Arousal releases nitric oxide
Sexual stimulation triggers nerves in the penis to release nitric oxide. Without arousal, nothing starts.
cGMP relaxes the vessels
Nitric oxide raises cGMP, which relaxes smooth muscle so blood flows into the penis.¹
PDE5 normally ends it
The enzyme PDE5 breaks cGMP down, which is what lets an erection subside afterwards.
Avanafil blocks PDE5
By blocking PDE5, avanafil helps a natural erection last long enough for sex — but only with stimulation.²
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Getting avanafil in Thailand
Thai regulatory status
Avanafil is a prescription-only medicine. Unlike sildenafil and tadalafil, which are well established and stocked across Thailand, avanafil is far less widely registered and marketed here. Its local availability cannot be assumed, and it is never sold legitimately over the counter.³
How to get it through Menscape
Menscape does not keep avanafil on the shelf. It is sold internationally under brand names such as Stendra. If a doctor decides it is the right option for you, it is ordered in per patient after your consultation, subject to legal supply. Where it cannot be sourced, the doctor will usually recommend a registered alternative such as sildenafil or tadalafil.
Safety vs the grey market
ED pills are among the most counterfeited medicines in the world. Products from street markets, unlicensed websites or messaging apps often contain the wrong dose, the wrong drug, or nothing at all. A real prescription also protects you from a dangerous interaction, such as taking a PDE5 inhibitor with a nitrate heart medicine you did not know you were on.⁴
Thai FDA warning. Buying prescription medicines from unlicensed online or street sellers is illegal and unsafe, and counterfeit erectile-dysfunction products are widespread. Registration status should be confirmed with the Thai FDA before sourcing.⁵
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Does it work? The evidence
Avanafil has been studied in randomised, placebo-controlled trials in men with erectile dysfunction, including men with diabetes and men who had undergone prostate surgery. In the pivotal trials, men taking avanafil 200 mg completed successful intercourse in roughly 57% of attempts, compared with about 27% on placebo, with matching gains on the standard IIEF erectile-function score.²
Its distinguishing features are speed and selectivity, not greater overall potency. Head-to-head and network analyses suggest the PDE5 inhibitors are broadly similar in how well they work; the real differences are onset, how long they last, and the side-effect profile. Because avanafil is highly selective for PDE5 over the related PDE6 enzyme, it is less likely than sildenafil to cause the bluish or blurred vision that some men notice. Results vary between individuals, and it only works with sexual stimulation.⁷
57%
Avanafil 200 mg
of intercourse attempts successful in trials
27%
Placebo
same measure, no active drug
Randomised, placebo-controlled trials in men with erectile dysfunction (Goldstein 2012; U.S. FDA label). Individual results vary.
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Side effects & who shouldn't take it
Common side effects
The most frequent are headache, flushing, nasal congestion, back pain and dizziness. They are usually mild and pass as the drug clears. Because avanafil is very selective for PDE5, vision-related effects are reported less often than with sildenafil.²
Serious but rare
Seek urgent care for an erection lasting more than 4 hours (priapism), which can damage tissue if untreated. Sudden loss of vision or hearing is rare but needs emergency attention. Stop and get help for chest pain, fainting or a severe drop in blood pressure.
Not suitable for
Anyone taking nitrates (for angina or chest pain) or riociguat must not take avanafil. It is also unsafe soon after a heart attack or stroke, with severe heart failure, very low or uncontrolled blood pressure, or severe liver problems. A doctor screens for all of this first.
Interactions & cautions
Combining avanafil with nitrates can cause a life-threatening blood-pressure drop. Alpha-blockers for blood pressure or prostate symptoms, strong CYP3A4 inhibitors (such as some antifungals and HIV medicines), grapefruit and heavy alcohol all need care or a lower dose. Tell the doctor every medicine you take.²
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Alternatives & combinations
Oral PDE5 · widely available
Sildenafil
The most established ED tablet, registered and stocked in Thailand. It is taken on demand and works in 30–60 minutes. A doctor may start here because supply and evidence are both strong.
Oral PDE5 · longer window
Tadalafil
Lasts far longer (up to around 36 hours) and can be taken as needed or in a low daily dose for more spontaneity. Also helps prostate symptoms. Widely registered and stocked here.
Root cause · essential
Treating the underlying cause
ED can be an early warning of heart disease, diabetes or low testosterone. A proper work-up, plus changes to blood pressure, weight and smoking, often improves erections and your wider health more than any tablet alone.
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How prescription works at Menscape
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Book a consultation with a men's health doctor.
Message us on WhatsApp or LINE
A few minutes on your phone: your symptoms, health history and current medicines. It is confidential and PDPA-protected.
Doctor consultation
A licensed Thai physician reviews your case by video call or in clinic at Asoke, checks your heart-health and confirms whether an ED medicine is appropriate.
Prescription, if suitable
If the doctor approves and avanafil can be legally sourced, it is ordered in for you per patient. If it is not available or not the best fit, the doctor will recommend a registered option such as sildenafil or tadalafil.
Follow-up
A check-in on how it is working and any side effects, with the dose or the medicine adjusted alongside your doctor if needed.
The doctor decides. Starting a conversation is not a commitment and does not guarantee a prescription. If a PDE5 inhibitor is not safe or right for you, your doctor will say so and discuss alternatives.
Medically reviewed by
Dr. Noppon Arunkajohnsak (Win)
Menscape Clinic, Bangkok
“Men often chase the newest, fastest pill when the real question is why the erections changed at all. Erectile dysfunction is common and very treatable, but it can also be the first sign of a heart or hormone problem, so the assessment matters more than the brand.”
- Reviewed
- 11 July 2026
- Next review
- January 2027
- Editorial standard
- Each guide is checked against the Thai FDA label and the primary literature, then reviewed by a licensed physician.
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Frequently asked questions
Can I buy avanafil over the counter in Thailand?
No. Avanafil is a prescription-only PDE5 inhibitor, so it must come from a doctor or a licensed pharmacy. In practice it is also far less commonly stocked in Thailand than sildenafil and tadalafil. Anything sold without a prescription is illegal and a counterfeit risk.
How fast does avanafil work?
It is the fastest-onset PDE5 inhibitor and can be taken 15–30 minutes before sex, with effects lasting around 6 hours. It still only works when you are sexually aroused. A heavy, fatty meal can slow it down a little.
How is avanafil different from sildenafil and tadalafil?
Avanafil acts faster than either and is more selective for the target enzyme, so it causes fewer vision-related side effects than sildenafil. Tadalafil lasts far longer (up to 36 hours), while avanafil gives a shorter, more on-demand window. Overall effectiveness across the class is broadly similar.
Is avanafil actually available in Thailand?
Its Thai registration and supply are limited compared with sildenafil and tadalafil, which are both stocked here. Menscape does not keep avanafil on the shelf but can order it per patient after a consultation where legal supply allows. If it cannot be sourced, the doctor will suggest a registered alternative.
Can I take avanafil with my heart medication?
Not if you take nitrates (for angina or chest pain) or a medicine called riociguat. Combined with a PDE5 inhibitor, nitrates can cause a dangerous, sometimes life-threatening drop in blood pressure. This is exactly why a doctor reviews your heart health and full medication list first.
Does food or alcohol affect it?
Avanafil is less affected by food than sildenafil, though a very fatty meal can still delay onset a little. Alcohol lowers blood pressure and can worsen dizziness and headache, so it is best kept light. Tell your doctor how much you drink.
Will avanafil cure my erectile dysfunction?
No. It treats the symptom for a few hours at a time, but it does not fix the underlying cause. Because ED can be an early sign of heart disease, diabetes or hormonal problems, the assessment behind the prescription is what matters most for your long-term health.
I already take an ED tablet from abroad — can I continue in Thailand?
Usually yes. A local doctor can review what you take and continue treatment, though they may switch you to a PDE5 inhibitor that is reliably registered and stocked in Thailand, such as sildenafil or tadalafil. Bring your current prescription and medical history.
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References
1. Hatzimouratidis K, et al. EAU Guidelines on Erectile Dysfunction. European Association of Urology. Accessed July 2026.
2. U.S. FDA. Stendra® (avanafil) prescribing information. Metuchen Pharmaceuticals. 2012, accessed July 2026.
3. Thai Food and Drug Administration — drug registration database, ndi.fda.moph.go.th. Accessed July 2026.
4. European Medicines Agency. Spedra (avanafil) — Summary of Product Characteristics. 2013.
5. Thai FDA consumer warnings on purchasing medicines from unlicensed online sellers, oryor.com. Accessed July 2026.
6. Goldstein I, et al. Avanafil for the treatment of erectile dysfunction: a multicenter, randomized, double-blind study in men with diabetes. J Sex Med. 2012;9(4):1122-1133.
7. Yuan J, et al. Comparative effectiveness and safety of oral PDE5 inhibitors for erectile dysfunction: a systematic review and network meta-analysis. Eur Urol. 2013;63(5):902-912.
This guide is educational information, not medical advice. Avanafil is a prescription-only medicine that must be assessed, prescribed and monitored by a licensed physician. Never combine it with nitrate medicines.
This guide is part of the Menscape ED library
Explore the condition hubStruggling with erections? Ask a doctor, not a forum.
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