Tadalafil vs Sildenafil vs Vardenafil vs Avanafil vs Udenafil: Complete Comparison of All ED Medicines

If you have been prescribed a tablet for erectile dysfunction — or if you have been quietly reading about them online at 1 a.m. without telling anyone — you have probably come across four familiar names: sildenafil, tadalafil, vardenafil and avanafil. And if you have read a little deeper, or seen medication from Korea or Southeast Asia, you may have come across a fifth: udenafil. They are sold under dozens of brand names, they all promise the same thing, and they all cost different amounts. It is genuinely confusing.

Here is the reassuring part. All five belong to the same family of medicines, called PDE5 inhibitors (short for phosphodiesterase type 5 inhibitors). They work through the same basic mechanism, the class as a whole is considered first-line treatment by both the European Association of Urology (EAU) and the American Urological Association (AUA), and all have a solid safety record when used correctly and under supervision.

What separates them is not “strength” in the way most men assume. It is timing, duration, food interaction, side-effect personality, availability, and how each one fits into your life and your other medical conditions.

This guide compares tadalafil vs sildenafil vs vardenafil vs avanafil vs udenafil across every dimension that actually matters to a patient — onset, duration, dosing, success rates, side effects, safety with heart medication, and availability realities in India. It also explains something most men never get told: why these tablets sometimes “don’t work” when the real problem is how they were taken.

Not sure which molecule suits you? Dr. Kalpesh K. Kapadia offers private, unhurried evaluation for erectile dysfunction in Ahmedabad. Book a confidential consultation.

What Are PDE5 Inhibitors and How Do They Work?

An erection is a blood flow event, not a willpower event. When a man is sexually aroused, nerves in the penis release a chemical messenger called nitric oxide. Nitric oxide triggers the production of another messenger called cGMP (cyclic guanosine monophosphate). cGMP relaxes the smooth muscle lining the arteries of the penis, blood rushes into the two spongy chambers (the corpora cavernosa), and the erection happens.

Naturally, the body also produces an enzyme called PDE5 whose job is to break cGMP down and end the erection. That is normal and necessary.

In erectile dysfunction, there is often not enough cGMP to begin with, or it is broken down too quickly. PDE5 inhibitors block that breakdown enzyme. The cGMP stays around longer, the arteries stay relaxed longer, and the erection becomes firmer and more reliable.

The single most important thing to understand

These tablets do not create desire and they do not create an erection on their own. They amplify a signal that must be started by sexual arousal and physical stimulation. A man who swallows a tablet and then sits waiting for something to happen will be disappointed — and will wrongly conclude the medicine failed.

The EAU guidelines specifically recommend that doctors fully explain this mechanism, because a large proportion of so-called “treatment failures” are actually cases where the medicine was never given a fair chance.

Meet the five molecules

Molecule	Common brand names (global)	Year introduced	Nickname
Sildenafil	Viagra and many Indian generics	1998	The original
Tadalafil	Cialis and many Indian generics	2003	The long-acting one
Vardenafil	Levitra, Staxyn	2003	The precise one
Avanafil	Stendra, Spedra	2012	The fast one
Udenafil	Zydena, Zudena	2005 (South Korea)	The middle-ground one

An important note on availability. Sildenafil and tadalafil are widely available as generics in India, which is why their price range is enormous — from a few rupees to a few hundred rupees per tablet for what is chemically the same molecule. Vardenafil and avanafil are available but less commonly stocked.

Udenafil is different. It was developed by Dong-A Pharmaceutical in South Korea and approved there in 2005. It is licensed in roughly a dozen countries — including South Korea, Russia, the Philippines and Malaysia — but it has not been approved by the US FDA or the European Medicines Agency, and it is not routinely available in India. Most of its clinical trial evidence comes from Korean study populations. It is included in this comparison because patients increasingly encounter it online or bring it back from travel, and because it genuinely occupies a useful middle ground — but no one should source it without a prescription and local regulatory approval.

Causes of Erectile Dysfunction — Why the Right Molecule Matters

Choosing between them is not a coin toss. The underlying cause of your ED, and your other medical conditions, genuinely shift which molecule fits best. Common causes include:

• Vascular disease (the most common cause after 40): Narrowed or stiff arteries from high blood pressure, high cholesterol or smoking reduce blood inflow. ED is often the first warning sign of heart disease, appearing 3–5 years before a cardiac event.
• Diabetes mellitus: Damages both the small blood vessels and the nerves. Diabetic men often need higher doses and respond better to a long-acting molecule with a longer window.
• Hypertension and its medication: Both the condition and certain drugs (older beta blockers, thiazide diuretics) can contribute.
• Hormonal causes: Low testosterone, thyroid disorders or a raised prolactin level. Importantly, PDE5 inhibitors work poorly when testosterone is low — the hormone must be corrected first.
• Neurological causes: Spinal cord injury, multiple sclerosis, Parkinson’s disease, or nerve injury after pelvic surgery such as radical prostatectomy.
• Psychological causes: Performance anxiety, relationship stress, depression, and the vicious cycle where one failed attempt creates fear of the next.
• Lifestyle factors: Smoking, excess alcohol, obesity, sedentary living, poor sleep and untreated sleep apnoea.
• Medication side effects: Certain antidepressants (especially SSRIs), antipsychotics, anti-androgens and some ulcer medicines.
• Peyronie’s disease and structural causes: Scar tissue in the penis causing curvature and painful or unreliable erections.

Risk Factors: Who Is More Likely to Need These Medicines?

• Age over 40 — prevalence rises steadily with each decade, though ED is never a “normal” part of ageing to be simply accepted.
• Type 2 diabetes — men with diabetes develop ED roughly 10–15 years earlier than men without.
• Known heart disease, high cholesterol or hypertension.
• Smokers and heavy alcohol users.
• Obesity and metabolic syndrome, particularly with a large waist circumference.
• Men after prostate, bladder or rectal surgery, where nerves may have been stretched or cut.
• Men on long-term psychiatric medication.
• Men with untreated obstructive sleep apnoea, which lowers night-time oxygen and testosterone.
• Chronic kidney disease or liver disease, which also affects how these drugs are cleared and may require dose reduction.

Symptoms: What Patients Actually Describe

Symptom	What it feels like	When to seek help
Difficulty getting an erection	Arousal is present but the penis does not become firm enough for penetration	If it happens in more than 50% of attempts over 3 months
Difficulty maintaining an erection	Firmness is achieved but lost partway through intercourse	Consistently over several weeks — this pattern often points to venous leak
Reduced firmness	“It’s there, but it’s only 60–70%”	Any persistent change from your own baseline
Loss of morning erections	Waking up without the erections you used to have	Suggests a physical rather than purely psychological cause — worth evaluating
Reduced desire alongside ED	No interest, plus difficulty	Suggests a hormonal cause — testosterone should be checked
Sudden, complete ED	Was normal, now completely absent overnight	Often psychological or medication-related; needs prompt evaluation
Painful or curved erection	Bend, pain or a palpable lump in the shaft	See a uroandrologist — this may be Peyronie’s disease, not simple ED
Erection lasting over 4 hours	Painful, persistent, unwanted erection	Medical emergency (priapism) — go to hospital immediately

Diagnosis: What Happens Before a Prescription Is Written

Any doctor who prescribes one of these molecules without a proper evaluation is doing you a disservice. A sound assessment includes:

1. Detailed history

• Onset, duration and pattern of the problem
• Presence or absence of morning and nocturnal erections
• Sexual desire, ejaculation and orgasm — these are separate functions
• Relationship context, stress, and partner factors
• Full medication and substance history
• Cardiovascular risk assessment and exercise tolerance

2. Validated questionnaires

The IIEF-5 (International Index of Erectile Function, 5-question version) or SHIM score gives an objective baseline severity and lets treatment response be measured meaningfully rather than by impression.

3. Physical examination

• Genital examination for penile plaques, testicular size and consistency
• Assessment of secondary sexual characteristics
• Blood pressure, pulse, waist circumference, BMI
• Peripheral pulses (a marker of general vascular health)
• Digital rectal examination where prostate symptoms coexist

4. Laboratory tests

• Fasting blood sugar and HbA1c
• Fasting lipid profile
• Morning total testosterone (8–11 a.m.), with free testosterone, LH and prolactin if low
• Thyroid function, renal and liver function where indicated
• PSA in men over 50, or over 40 with a family history

5. Specialised investigations (selected cases)

• Penile Doppler ultrasound after an intracavernosal injection, to distinguish arterial insufficiency from venous leak
• Nocturnal penile tumescence testing to separate psychogenic from organic causes
• Cardiological clearance before resuming sexual activity in men with significant cardiac disease

Treatment Options: The Full Comparison

Here is the head-to-head comparison that most patients come looking for.

The core comparison table

Feature	Sildenafil	Tadalafil	Vardenafil	Avanafil	Udenafil
Usual doses	25, 50, 100 mg	10, 20 mg on demand; 2.5–5 mg daily	5, 10, 20 mg (plus 10 mg ODT)	50, 100, 200 mg	100, 200 mg on demand; 50–75 mg daily
Typical starting dose	50 mg	10 mg	10 mg	100 mg	100 mg
Onset of action	30–60 min	~30 min (peak ~2 h)	~25–30 min	15–30 min (fastest)	~30 min (peak 0.8–1.3 h)
Duration of effect	Up to ~12 h (practically 4–6 h)	Up to 36 h	~8–10 h	~6 h+	Up to ~12 h
Half-life	~3–4 h	~17.5 h	~4 h	~6–17 h	~10–12 h
Effect of fatty food	Significant — delays and reduces absorption	None — unaffected by food	Significant — take on an empty stomach	Minor delay only	Minimal — overall absorption not meaningfully affected
Effect of alcohol	Best avoided in excess	Best avoided in excess	Best avoided in excess	Best avoided in excess	Best avoided in excess
Daily-dosing option	No	Yes (2.5–5 mg)	No	No	Yes (50–75 mg, where licensed)
Also licensed for BPH/prostate symptoms	No	Yes (5 mg daily)	No	No	Studied for BPH/LUTS; licensing varies by country
Signature side effect	Blue-tinged or blurred vision (~1%)	Backache and muscle ache (~3%)	Nasal congestion (~10%)	Fewest side effects overall	Headache and flushing; notably no muscle ache
Availability in India	Widely available	Widely available	Available, less common	Available, less common	Not routinely available
Regulatory status	FDA, EMA, CDSCO approved	FDA, EMA, CDSCO approved	FDA, EMA approved	FDA, EMA approved	Approved in ~13 countries; not FDA or EMA approved
Best suited to	Planned intimacy, cost-conscious patients	Spontaneity, weekend cover, men with prostate symptoms	Men needing a reliable, precise window	Men wanting speed and minimal side effects	Men wanting a longer window than sildenafil without tadalafil’s 36-hour tail or backache

Common side effects side by side

Side effect	Sildenafil	Tadalafil	Vardenafil	Avanafil	Udenafil
Headache	~13%	~15%	~16%	~9%	Most common effect
Facial flushing	~10%	~4%	~12%	~4%	Second most common
Indigestion / acidity	~5%	~12%	~4%	Uncommon	Uncommon
Blocked nose	~1%	~4%	~10%	~2%	Uncommon
Back or muscle ache	Uncommon	~3%	Uncommon	Uncommon	Not reported in trials
Visual disturbance	~1%	Rare	Rare	Rare	Very rare (0–0.6%)

Why the side effects differ — the selectivity story

This is the part that explains the whole table, and it is worth understanding.

PDE5 is not the only phosphodiesterase enzyme in the body. Two others matter here:

• PDE6 lives in the retina. A drug that also blocks PDE6 causes the classic blue tinge, light sensitivity or blurring. Sildenafil is the least selective here, which is why it owns the visual side effect.
• PDE11 is found in skeletal muscle. A drug that also blocks PDE11 causes muscle ache and backache. Tadalafil has relatively low selectivity against PDE11 (a ratio of around 7), which is exactly why roughly 3% of men on tadalafil get backache.

Udenafil is interesting precisely here: its selectivity against PDE11 is very high (a ratio around 96, more than ten times tadalafil’s), and muscle ache and backache were not reported in its trials at all. Its PDE6 selectivity is similar to sildenafil’s, yet reported visual disturbance stayed under 1%.

The practical upshot: if a man does well on tadalafil’s longer window but cannot tolerate the backache, udenafil is a pharmacologically logical alternative — where it is legally available and appropriately prescribed.

The non-tablet ladder

PDE5 inhibitors are first-line, not only-line. If they are not suitable or not sufficient, the ladder continues:

Option	How it works	Best for
Lifestyle and risk-factor correction	Improves the blood vessel lining itself	Every patient, always — this is foundational, not optional
Testosterone optimisation	Restores the hormonal environment PDE5 inhibitors need	Men with confirmed, symptomatic low testosterone
Vacuum erection device	Mechanically draws blood in; a ring holds it	Men who cannot take or prefer to avoid drugs
Intracavernosal injection (alprostadil)	Directly relaxes penile smooth muscle	Non-responders to tablets; post-prostatectomy rehabilitation
Penile implant (prosthesis)	Surgically placed device producing a reliable erection	Severe ED not responding to anything else; highest satisfaction rates of all options — see our penile prosthesis page

Advanced Treatment Options and Newer Developments

Low-intensity extracorporeal shockwave therapy (Li-ESWT). Acoustic waves are applied to the penile shaft to stimulate new blood vessel formation. Unlike tablets, the aim is to improve the underlying blood supply rather than treat a single episode. Evidence is most encouraging in men with mild-to-moderate vascular ED and a good response to tablets. Guidelines currently place it as an option with moderate evidence — honest counselling matters, as results vary considerably and are not permanent for everyone.

Combination therapy. For men who partially respond, a daily low-dose tadalafil regimen combined with an on-demand higher dose, or a PDE5 inhibitor combined with testosterone replacement in hypogonadal men, can rescue a substantial number of apparent non-responders.

Penile rehabilitation after prostate surgery. Early, scheduled use of PDE5 inhibitors — often daily low-dose tadalafil — after nerve-sparing radical prostatectomy aims to maintain oxygenation of penile tissue and preserve function while the nerves recover. Protocols vary between centres and benefit is still debated, but it is standard practice in most specialist units.

Newer molecules within the same class. Udenafil is the clearest example of continued development within the PDE5 inhibitor family rather than beyond it — engineered for a mid-length window with improved PDE11 selectivity. Others such as mirodenafil and lodenafil are approved in individual countries (South Korea and Brazil respectively) and remain regional rather than global options. Their existence is a reminder that “newer” does not automatically mean “better for you” — it usually means a different balance of the same trade-offs.

Orodispersible and film formulations. Vardenafil is available as a 10 mg orally disintegrating tablet that dissolves on the tongue without water — discreet and useful for men who dislike swallowing tablets. Sildenafil and tadalafil oral films exist in some markets for the same reason.

Regenerative approaches. Platelet-rich plasma (PRP) and stem-cell-based therapies for ED are being actively studied. These remain experimental. Major guidelines do not recommend them outside clinical trials, and any clinic promising guaranteed results from them should be treated with caution.

Step-by-Step: How to Take These Medicines Correctly

Getting this right is the difference between “it worked” and “it didn’t work”.

1. Get properly evaluated first. Never take a friend’s tablet or an online purchase. The evaluation is what keeps you safe — especially the cardiac and nitrate check.
2. Confirm every medicine you take. Tell your doctor about nitrates, nicorandil, alpha-blockers, blood pressure medicines, antifungals, HIV medicines, antibiotics and any recreational substances.
3. Take the tablet with plain water, at the interval your doctor specifies — roughly 60 minutes before for sildenafil and vardenafil, 30–60 minutes for tadalafil and udenafil, and 15–30 minutes for avanafil.
4. Mind the meal. Sildenafil and vardenafil should ideally be taken on an empty stomach or at least two hours after a heavy or oily meal. Tadalafil can be taken with food without any loss of effect. Avanafil is only mildly affected, and udenafil’s overall absorption is not meaningfully changed by food.
5. Limit alcohol.
6. Create genuine arousal. Foreplay and physical stimulation are required. The tablet is a facilitator, not a trigger.
7. Do not exceed one dose in 24 hours — for any of these molecules.
8. Give it a fair trial: at least 6–8 attempts at an adequate dose before declaring it a failure. This is the single most common mistake patients make.
9. Report back for dose adjustment. Many men started on a low dose need a step up. Around half of initial non-responders to 50 mg sildenafil respond when moved to 100 mg.
10. If one molecule doesn’t suit you, switch. Failing on sildenafil does not mean failing on tadalafil, avanafil or udenafil. Side-effect profiles and personal response genuinely differ.
11. Do not import medication on your own. This applies particularly to udenafil, which is not approved in India — self-importing an unapproved drug carries both counterfeit risk and no safety net if something goes wrong.

Recovery and Response Timeline

Because these are medicines rather than an operation, the “recovery” timeline is really a response timeline.

First 24 hours: The tablet is active. Any headache, flushing or nasal congestion usually appears within the first couple of hours and settles as the drug clears. Mild side effects on the first dose often lessen with subsequent doses.

First week: With one to three attempts, you begin to learn your own timing — how long your body actually takes, and how food and stress affect it. Do not judge the medicine yet.

Weeks 2–6: This is the honest assessment window. After 6–8 properly conducted attempts at an optimised dose, a clear pattern emerges. Your doctor can now decide whether to continue, increase the dose, or switch molecules.

Months 2–3: If daily low-dose tadalafil has been chosen, its full benefit — including improvement in urinary symptoms in men with an enlarged prostate — typically becomes apparent by 4–12 weeks.

Long term: Many men find that as confidence returns and lifestyle changes take effect, they need the tablet less frequently. Others, particularly those with diabetes or vascular disease, continue long-term. Long-term use of PDE5 inhibitors has a reassuring safety record and there is no evidence of dependence or of the medicine “stopping working” through tolerance.

Benefits of PDE5 Inhibitor Therapy

• Non-invasive and reversible — no surgery, no injections, nothing permanent.
• Strong evidence base across more than 25 years and millions of patients.
• High overall response rates in appropriately selected men.
• Restores confidence and often breaks the anxiety–failure cycle that worsens ED.
• Improves relationship and quality-of-life scores, for both partners.
• Tadalafil 5 mg daily treats two conditions at once — erectile dysfunction and the urinary symptoms of an enlarged prostate.
• Flexible options — a molecule exists for the man who wants speed, the one who wants spontaneity, and the one who wants the lowest cost.
• Widely available as affordable generics in India.
• Prompts a wider health check — many men discover undiagnosed diabetes or hypertension during their ED evaluation, which may be the most valuable outcome of all.

Complications and Risks — the Honest Version

Common and usually mild: headache, facial flushing, indigestion, nasal congestion, dizziness, back or muscle ache (mainly tadalafil), and transient blue-tinged or blurred vision (mainly sildenafil, from mild cross-action on the PDE6 enzyme in the retina).

Uncommon but important:

• Symptomatic low blood pressure, especially with alpha-blockers, other antihypertensives or alcohol.
• Priapism — an erection lasting more than four hours. Rare with tablets, but a genuine emergency requiring immediate hospital attention to avoid permanent damage.
• NAION (non-arteritic anterior ischaemic optic neuropathy) — sudden painless loss of vision in one eye. Very rare; stop the medicine and seek urgent ophthalmology review.
• Sudden hearing loss or ringing in the ears — very rare; stop and seek review.
• QT-interval effects — vardenafil carries a specific caution in men with a prolonged QT interval or on class IA/III antiarrhythmic drugs.

Absolute contraindication — this one is not negotiable:

Never combine any PDE5 inhibitor with nitrates. This includes nitroglycerin/sorbitrate tablets or sprays, isosorbide mononitrate or dinitrate, nicorandil, and recreational “poppers” (amyl nitrite). The combination can cause a catastrophic drop in blood pressure. If you take nitrates for angina, tell every doctor you see, and tell emergency staff that you have taken an ED tablet — the safe waiting interval before a nitrate can be given is generally around 24 hours for sildenafil and vardenafil and around 48 hours for tadalafil.

Use with caution or avoid in: recent heart attack or stroke, unstable angina, severe uncontrolled hypertension or hypotension, severe heart failure, significant liver or kidney impairment, retinitis pigmentosa, and men who are not physically fit enough for sexual activity. Dose reduction and specialist input are needed in many of these situations.

Drug interactions requiring dose adjustment: ketoconazole, itraconazole, clarithromycin, erythromycin, ritonavir and similar protease inhibitors all raise blood levels of these drugs. Riociguat (for pulmonary hypertension) is contraindicated with all of them.

Prognosis: What Realistic Success Looks Like

Across large studies, roughly 60–80% of men respond well to an appropriately chosen and correctly dosed PDE5 inhibitor. Response is generally best in psychogenic and mild vascular ED, and more modest in long-standing diabetes, severe vascular disease, and after non-nerve-sparing prostate surgery.

Of the men who appear not to respond initially, a large share can still be rescued — by correcting the dose, correcting the technique, correcting low testosterone, or switching molecules. Genuine non-response after all of that is uncommon, and for those men, injections and penile implants offer excellent and highly satisfying results.

These medicines manage the symptom; they do not cure the underlying cause. A man whose ED stems from uncontrolled diabetes will keep needing the tablet unless the diabetes is addressed. Conversely, men who take lifestyle change seriously — weight loss, exercise, quitting smoking, treating sleep apnoea — sometimes improve enough to reduce or stop medication. Individual results vary, and no honest doctor will promise a specific outcome.

Prevention: Protecting Erectile Function for the Long Term

• Stop smoking. Nothing else you do for your erections will matter as much if you continue.
• Move your body — 150 minutes of moderate aerobic activity per week measurably improves erectile function.
• Control diabetes, blood pressure and cholesterol with the same seriousness you’d apply to your heart, because it is the same set of blood vessels.
• Lose central weight. Even a 5–10% reduction improves both testosterone and vascular function.
• Sleep 7–8 hours and get snoring or daytime sleepiness assessed for sleep apnoea.
• Keep alcohol moderate and avoid recreational drugs.
• Manage stress and treat depression — and be aware some antidepressants contribute; alternatives exist.
• Review your medications periodically with your doctor for ED-contributing drugs.
• Do not ignore early symptoms. ED can be the earliest signal of cardiovascular disease. Getting evaluated early may protect far more than your sex life.

Frequently Asked Questions

Which is the best ED tablet — tadalafil, sildenafil, vardenafil, avanafil or udenafil?

There is no universally “best” one. All are effective options within the same class, and head-to-head evidence does not establish a clear winner. The best molecule is the one that matches your lifestyle, your other medical conditions, your side-effect tolerance, your budget and what is legally available where you live — decided with a doctor after evaluation.

Which ED medicine works the fastest?

Avanafil has the fastest onset, working for many men within 15–30 minutes. Vardenafil is next, followed by sildenafil, tadalafil and udenafil at around 30–60 minutes. Individual response varies.

Which ED tablet lasts the longest?

Tadalafil, by a wide margin. Its effect can last up to 36 hours, which is why it is nicknamed “the weekend tablet”. This is also why it can be taken as a low daily dose. Udenafil sits second at up to around 12 hours.

What is udenafil and how is it different?

Udenafil (brand names Zydena, Zudena) is a PDE5 inhibitor developed in South Korea and approved there in 2005. It occupies the middle ground: a half-life of around 10–12 hours and an effect lasting up to about 12 hours — longer than sildenafil, shorter than tadalafil. Its distinguishing feature is high selectivity against the PDE11 enzyme, which is why muscle ache and backache were not reported in its trials.

Is udenafil available in India?

Not routinely. Udenafil is approved in around a dozen countries including South Korea, Russia, the Philippines and Malaysia, but it has not been approved by the US FDA or the European Medicines Agency and is not a standard prescription option in India. Men sometimes encounter it online or bring it back from travel — buying an unapproved medicine this way carries real counterfeit and safety risks and is not advisable.

Is udenafil better than tadalafil?

Not better — different. Udenafil offers a shorter window (about 12 hours versus up to 36) which some men prefer, and it appears far less likely to cause the backache that affects around 3% of tadalafil users. Against that, tadalafil has a vastly larger evidence base, global regulatory approval, a licensed daily dose, an additional licence for prostate symptoms, and ready availability in India. For most patients here, tadalafil remains the more practical choice.

Is tadalafil stronger than sildenafil?

No — “stronger” is the wrong frame. Tadalafil is longer-acting, not more powerful. A 20 mg tadalafil and a 100 mg sildenafil are not comparable numbers; they are different molecules with different potencies per milligram.

Can I take these tablets every day?

In India, only tadalafil is designed and licensed for daily use, at 2.5–5 mg. Sildenafil, vardenafil and avanafil are intended for on-demand use, with a maximum of one dose in 24 hours. Udenafil has been studied and licensed in some countries as a 50–75 mg daily dose, but this is not an option available here.

Do I need to be sexually aroused for these to work?

Yes, absolutely. All five require sexual arousal and physical stimulation. They do not produce an automatic erection and they do not increase sexual desire.

Can I take an ED tablet if I have heart disease or high blood pressure?

Often yes — many cardiac patients use them safely — but only after cardiac assessment, and never if you take nitrates or nicorandil in any form. Discuss this with both your cardiologist and your urologist.

Does food affect these medicines?

Significantly for sildenafil and vardenafil — a heavy, oily meal delays and blunts their effect. Tadalafil is unaffected by food, avanafil is only mildly delayed, and udenafil’s overall absorption is largely unchanged. This is a genuinely important practical difference.

Why did the tablet not work for me?

The most common reasons are: dose too low, insufficient time before intercourse, taken after a heavy meal or alcohol, inadequate sexual stimulation, too few attempts before giving up, untreated low testosterone, or an underlying cause that needs separate treatment. True non-response is far less common than assumed — get reviewed rather than giving up.

Can these tablets cure erectile dysfunction permanently?

No. They treat the symptom effectively while the tablet is active. Lasting improvement comes from addressing the underlying cause — vascular health, diabetes control, hormones, weight, smoking and psychological factors.

Are ED tablets safe to use long term?

Long-term use has a reassuring safety record spanning more than two decades. There is no evidence of dependence, and no evidence that the body builds tolerance requiring ever-higher doses. Regular medical review is still sensible.

Do these medicines affect fertility or sperm?

Current evidence does not show any meaningful adverse effect on sperm quality or fertility at standard doses. If you are trying to conceive, discuss it with your doctor so your overall fertility picture is assessed properly.

Is it safe to buy ED tablets online without a prescription?

No. Counterfeit ED medication is one of the most commonly faked drug categories worldwide, with tablets found containing wrong doses, wrong molecules or contaminants. Beyond the counterfeit risk, buying without a prescription skips the nitrate check that exists to protect your life.

Can I switch from one molecule to another?

Yes, and it is a standard clinical strategy. Poor response or troublesome side effects with one molecule frequently resolve with another — a man troubled by sildenafil’s visual effects often does well on tadalafil or avanafil, and a man troubled by tadalafil’s backache often does well on a shorter-acting molecule. This should be done under medical guidance rather than by self-experimentation.

Will I become dependent on these tablets?

There is no physical dependence. Some men develop psychological reliance — a fear of attempting intercourse without one. This is manageable and worth raising with your doctor, as it is common and treatable.

Myths vs Facts

Myth	Fact
These tablets are aphrodisiacs that increase desire	They only improve blood flow. Desire comes from hormones, mood and attraction — not from the tablet
The higher the dose, the better the erection	Beyond the optimal dose, extra milligrams add side effects, not firmness
ED tablets are only for old men	ED affects men in their 20s and 30s too, often from stress, anxiety, smoking or metabolic problems
Taking them causes heart attacks	In appropriately assessed men they are cardiac-safe. The danger is combining them with nitrates, or sexual exertion in someone with undiagnosed severe heart disease
If one brand didn’t work, none will	Response to different molecules genuinely varies; switching rescues many men
Herbal or “ayurvedic” ED products are safer	Many marketed products have been found illegally adulterated with undeclared sildenafil — carrying the same risks with none of the oversight
You’ll need them forever once you start	Many men reduce or stop as underlying causes are treated and confidence returns
They will make you last longer in bed	They treat erection quality, not premature ejaculation — a separate condition with separate treatment
Generic versions are inferior	Quality-assured generics contain the same molecule at the same dose and work equivalently
A newer molecule must be a better molecule	Udenafil and avanafil are newer than sildenafil, but “newer” means a different balance of onset, duration and side effects — not superior results
If a drug is approved abroad it must be safe to order here	Regulatory approval is country-specific for good reason, and imported unapproved medicines are a leading source of counterfeits
ED is purely psychological	The majority of cases after 40 have a demonstrable physical component, usually vascular

Expert Insight

In Dr. Kapadia’s clinical experience, the most frequent reason a man arrives saying “these tablets don’t work for me” is not the molecule — it is how it was used. Tablets taken fifteen minutes before intercourse after a heavy dinner and two drinks, without adequate foreplay, at the lowest available dose, tried twice, and then abandoned: this pattern accounts for a striking proportion of apparent treatment failures seen in practice.

Dr. Kapadia emphasises that molecule selection should be a lifestyle decision as much as a pharmacological one. A man in a stable relationship who values spontaneity and dislikes planning will usually do better on tadalafil — particularly if he also has troublesome urinary symptoms from an enlarged prostate, in which case a single daily 5 mg tablet addresses both problems. A man who is intolerant of headache and flushing, or who wants a rapid, discreet option, may be better served by avanafil. A man with predictable, planned intimacy and cost as a real consideration often does perfectly well on sildenafil.

On udenafil specifically, Dr. Kapadia takes a measured view. It is a well-designed molecule with a sensible pharmacological profile, and the near-absence of backache in its trial data is a real advantage over tadalafil for men troubled by that particular effect. But it is not approved in India, its evidence base is smaller and geographically narrow, and the versions men obtain online are frequently of unverifiable origin. In practice, the same clinical goal — a longer window without muscle ache — can usually be achieved with an approved molecule at an adjusted dose. Patients who arrive with imported strips are counselled honestly rather than dismissed, and switched onto something that can be prescribed, monitored and trusted.

He also stresses that erectile dysfunction should never be treated as an isolated complaint. In practice, a significant number of men attending for ED are found to have previously undiagnosed diabetes, hypertension or dyslipidaemia. The erection is often the messenger, and the message concerns the arteries. Treating the symptom while ignoring that message is a missed opportunity to prevent something far more serious.

Finally, Dr. Kapadia notes that no responsible practitioner should promise a specific result. Every treatment plan must be individualised after a proper evaluation, adjusted over time, and reviewed honestly — including the willingness to move up the treatment ladder when tablets are genuinely not enough.

Key Takeaways

• Sildenafil, tadalafil, vardenafil, avanafil and udenafil are all PDE5 inhibitors, and this class is the recommended first-line treatment for erectile dysfunction.
• The real differences are onset, duration, food interaction, side-effect personality and availability — not raw strength.
• Avanafil is fastest (15–30 minutes). Tadalafil lasts longest (up to 36 hours) and is the only one in India available as a daily dose and licensed for prostate symptoms. Udenafil sits in the middle at around 12 hours.
• Side-effect differences are explained by enzyme selectivity: sildenafil’s visual effects come from PDE6 cross-action, tadalafil’s backache from PDE11 cross-action, and udenafil’s high PDE11 selectivity is why muscle ache was not reported in its trials.
• Sildenafil and vardenafil are meaningfully affected by fatty meals; tadalafil, avanafil and udenafil far less so.
• Udenafil is not approved by the FDA or EMA and is not routinely available in India — it should not be self-imported or bought online.
• All five require sexual arousal — none produces an automatic erection.
• Never combine any of them with nitrates or nicorandil. This is an absolute contraindication.
• Most “failures” are fixable: adjust the dose, correct the technique, check testosterone, or switch molecules — give it 6–8 proper attempts first.
• These medicines manage the symptom, not the cause; lifestyle and metabolic control determine long-term outcomes.
• ED can be an early warning sign of cardiovascular disease — evaluation matters beyond the bedroom.
• Selection must be individualised by a qualified doctor; results vary between individuals and no outcome can be guaranteed.

Conclusion

If you have been trying to decide between tadalafil, sildenafil, vardenafil, avanafil and udenafil, the honest answer is that they are all good medicines — and the question worth asking is not “which is strongest?” but “which one fits my body, my health conditions, my life, and what I can actually obtain safely and legally?”

That question has a genuinely different answer for a 35-year-old with performance anxiety, a 55-year-old with diabetes and prostate symptoms, and a 65-year-old on three cardiac medications. It deserves a proper conversation rather than a guess, and certainly rather than an unregulated online purchase. You can read more about our full erectile dysfunction treatment approach in Ahmedabad.

Erectile dysfunction is common, it is treatable, and it is nothing to be ashamed of. It is also, quite often, the body’s first polite warning about something bigger. A private, unhurried consultation with a qualified Uroandrologist will get you a molecule chosen for you, a dose that actually works, and — just as importantly — a check on the heart and metabolic health sitting behind the symptom.

You do not have to keep researching this alone at midnight. Book the evaluation.

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Choosing the right medicine — and the right dose — needs a proper evaluation, not guesswork. Consultations at Pratham IVF & Urology Clinic, unhurried and judgement-free, and include the cardiac and hormonal checks that make treatment both effective and safe.

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Medical disclaimer: This article is for general education only and is not a substitute for a personal consultation with a qualified doctor. It does not constitute a prescription. Erectile dysfunction medicines are prescription-only and must be selected, dosed and monitored individually after proper evaluation — including a check for nitrate use and cardiac fitness. Outcomes vary between individuals and no result can be guaranteed. Never take, import or purchase these medicines without a valid prescription. If you experience an erection lasting more than four hours, sudden loss of vision or hearing, chest pain or fainting, seek emergency hospital care immediately.