In short
The four standard tablets work about equally well. What separates them is onset, duration and how food affects them.
| Sildenafil | Take 60 minutes before. Lasts 4 to 5 hours. Longest safety record |
| Vardenafil | 60 minutes, or 30 for the dissolving form. Lasts 4 to 5 hours |
| Tadalafil | Effective up to 36 hours. Also available as a low daily dose |
| Avanafil | As little as 15 minutes before. Lasts 4 to 5 hours |
Successful intercourse in 68 to 69 per cent of men against 33 to 35 per cent on placebo.
Treatment Overview
How well do they work?
Well. Across the four drugs, successful intercourse rates are 68 to 69 per cent compared with 33 to 35 per cent on placebo.
For sildenafil specifically, a meta analysis of 27 trials in 6659 men found successful intercourse in 57 per cent against 21 per cent on placebo. They also work in men with diabetes and after nerve sparing prostate surgery.
How to actually take them
- On an empty stomach for maximum effect, although they can be taken with food
- Timing differs. Sildenafil tablet, vardenafil and tadalafil at 60 minutes. Avanafil, dissolving vardenafil and sildenafil oral film at 30 minutes or less
- They need arousal. They do not produce an erection on their own. Without sufficient sexual stimulation they will not work
- A high fat meal delays sildenafil and lowers vardenafil’s peak by about 18 per cent. It does not affect tadalafil
Retrying with proper instruction rescues about 25 to 30 per cent of men previously labelled as non responders. That is worth knowing before concluding the treatment failed.
Choosing between them
The choice comes down to your preferences: cost, ease of use, how long you want it to last, and side effects.
- Want spontaneity: tadalafil, effective up to 36 hours, or a low daily dose which removes the timing question entirely
- Want speed: avanafil, the only one approved for onset as early as 15 minutes
- Want the longest track record: sildenafil
- Eating first: tadalafil and dissolving vardenafil are not delayed by a high fat meal
Daily dosing
Low dose daily tadalafil, at 2.5 or 5 mg, works about as well as higher on demand doses, and the 5 mg dose is more effective than 2.5 mg.
In one trial of 268 men, those on daily tadalafil had successful penetration in 36 to 39 per cent against 11 per cent on placebo, successful intercourse in 45 to 50 per cent against 13 per cent, and no erectile dysfunction in 50 per cent against 8 per cent.
It can be continued indefinitely, may be more effective than on demand dosing for long term erectile and blood vessel function, and also treats prostate related urinary symptoms, which suits men who have both. It is not used if kidney function is below a creatinine clearance of 30.
What if tablets are not enough?
Second line options in order: a vacuum device first, being non invasive and less expensive, then penile self injection or intraurethral alprostadil. A penile implant is the option for men who cannot use or have not responded to anything else.
Where testosterone fits
Where testosterone is unequivocally low, it is added to a PDE5 inhibitor rather than used instead of one. Testosterone alone improves libido reliably but is less effective for erections.
Combination therapy appears most useful for men with low testosterone who did not respond to a PDE5 inhibitor alone, and the greatest gains were in men with more severe deficiency, below 231 ng/dL.
Who Is a Good Candidate?
- Your cause has been assessed and your cardiac risk is low
- You have tried a tablet without proper instruction on timing and use
- You want a treatment that fits how you actually live rather than the first one on the list
- You have both erectile dysfunction and prostate related urinary symptoms
- Tablets have not worked and you want to know what the next options are
- You take nitrates in any form, regularly or occasionally. This is an absolute contraindication
- You take an alpha blocker, which needs the dose and timing adjusted rather than ruling treatment out
- Sudden loss of vision or hearing after taking a dose, which needs immediate assessment
What Happens During the Consultation
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1
Confirming it is safe
Nitrates in any form are an absolute contraindication. Alpha blockers need care because of the risk of low blood pressure. Cardiac risk must already have been graded, and high risk needs cardiology review first.
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2
Matching the drug to your life
Onset, duration, whether you eat before, and cost. Tadalafil for spontaneity or as a daily dose, avanafil for speed, sildenafil for the longest track record.
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3
Instruction that is part of the prescription
Empty stomach, correct timing for the drug chosen, and the fact that arousal is still required. This alone rescues a quarter to a third of apparent treatment failures.
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4
A baseline and a review
A validated score before treatment, so improvement is a defined change rather than an impression, and a review to adjust dose or switch drug before concluding anything has failed.
Program Structure & Follow-Up
The first weeks
- Start at the standard dose: sildenafil 50 mg, tadalafil 10 mg on demand or 5 mg daily, avanafil 100 mg
- If tolerated but not fully effective, the dose goes up before the drug is changed
- If not tolerated, a different drug in the same class often suits better
Measuring the result
Against a validated score rather than an impression. A clinically meaningful improvement is a two point rise for mild erectile dysfunction, five for moderate and seven for severe.
Side effects, in proportion
| Flushing | About 12 per cent |
| Headache | About 11 per cent |
| Indigestion | About 5 per cent |
| Nasal congestion | Reported, less common |
| Blue tinged vision | Occasional with sildenafil only. Lasts two to three hours and resolves on its own |
The rare ones worth knowing
A form of optic nerve damage has been reported, and the risk appears raised even after allowing for shared risk factors such as age, blood pressure, cholesterol and diabetes. Serious retinal problems have also been reported. The absolute risk of any of these is very low, at 2 to 4 cases per 10,000 person years.
Sudden hearing loss has been reported rarely, usually in one ear, within the first 24 hours, and temporary in about a third of cases.
Any visual or hearing symptom needs prompt assessment. Routine eye monitoring is not recommended in men without symptoms or known retinal disease.
Benefits, Limits & Safety
Realistic expectations
These drugs restore function in most men, they do not increase desire, and they do not work without arousal. A man whose problem is low libido rather than erections will not be helped by them.
They also do not treat the cause. Where the cause is vascular, the cardiovascular risk still needs managing in its own right.
What improves the odds alongside medication
- Aerobic exercise, which improved erectile function against placebo in a meta analysis of 11 trials
- Weight loss, including after bariatric surgery, which also raises testosterone
- Stopping smoking
- Treating sleep apnoea, which improved erectile function in some studies
- Reviewing antidepressants and blood pressure medication
The absolute limits
Nitrates in any form, regularly or occasionally, rule these drugs out completely. Even with tadalafil’s longer half life, it is suggested that nitrates be avoided for at least 48 hours after the last dose.
Alpha blockers require caution because of the risk of a sharp drop in blood pressure, and avanafil is started at the lower dose in men taking one.
An honest note on melanoma
Some studies reported a small association between PDE5 use and melanoma. A further study concluded it was unlikely to be causal, since greater exposure was not linked to higher risk and men taking these drugs had more sun exposure. It is worth knowing about rather than worrying about.
They work well
Successful intercourse in 68 to 69 per cent of men against 33 to 35 per cent on placebo, and comparable results in men with diabetes.
Dose before drug
If tolerated but not fully effective, the dose goes up before the drug is changed. Improvement is measured against a validated baseline score.
Absolute and relative
Nitrates in any form are absolute. Alpha blockers need care. Any sudden visual or hearing symptom needs prompt assessment.
Cost & Program Investment
The consultation is quoted individually, and the medication is an ordinary prescription bought from a pharmacy at pharmacy prices, which usually costs less than the online services selling the same molecules. There is no subscription and no minimum course. Second line options, if they become relevant, are quoted before they are arranged.
Frequently Asked Questions
They work about equally well. The choice is about onset, duration, food effects and cost. Tadalafil lasts up to 36 hours, avanafil can work in 15 minutes, and sildenafil has the longest safety record.
Not yet. Retrying with proper instruction rescues about 25 to 30 per cent of apparent non responders. Take it on an empty stomach, at the right interval for that drug, and remember it needs arousal to work.
Tadalafil has a licensed low daily dose of 2.5 or 5 mg, and 5 mg is more effective. It can be continued indefinitely and removes the question of timing entirely. It is not used if kidney function is significantly reduced.
Not if it includes nitrates in any form, regularly or occasionally. That is absolute. Alpha blockers need care rather than exclusion. Bring your full medication list.
Flushing in about 12 per cent, headache in about 11 and indigestion in about 5. Sildenafil occasionally causes a blue tinge to vision that lasts two to three hours and resolves on its own.
Only if your testosterone is genuinely low, and then alongside rather than instead. Testosterone alone improves desire reliably but is less effective for erections, and combination helps most in men who did not respond to the tablet alone.
There are second line options. A vacuum device is usually tried first because it is non invasive and less expensive, followed by self injection or intraurethral treatment, with an implant for men who cannot use or have not responded to anything else.
Evidence
Where this information comes from
Every figure on this page is taken from the sources below. All of them are free to read, so you can check them yourself.
This page is general medical information and does not replace a personal consultation. Trial results are averages across large groups, not a prediction for any one person.