In short
Sildenafil, sold as Viagra and as generic sildenafil, is a tablet for erectile dysfunction taken about 1 hour before sex that works for about 4 hours. In 27 trials with 6,659 men, sexual intercourse was successful in 57 percent of attempts on sildenafil against 21 percent on placebo, close to 3 times as often. Sildenafil needs a prescription in Dubai and is never combined with nitrates.
Treatment Overview
What is sildenafil?
Sildenafil is a phosphodiesterase type 5 (PDE5) inhibitor, the tablet class used first for erectile dysfunction. Viagra is the original brand; generic sildenafil contains the same active ingredient. Clinical guidance recommends a PDE5 inhibitor as first treatment for erectile dysfunction because it works well, is easy to use and has a favourable side effect profile. All treatments for erectile dysfunction compared: erectile dysfunction treatment.
How does sildenafil work?
Sildenafil keeps the natural erection signal active for longer. Sexual arousal releases nitric oxide in the penis, which raises cyclic GMP (cyclic guanosine monophosphate, the messenger that relaxes the blood vessels); the PDE5 enzyme breaks that messenger down, and sildenafil blocks the enzyme. Sildenafil therefore does not cause an erection without sexual stimulation.
How is sildenafil taken?
Sildenafil is taken about 1 hour before sex, on an empty stomach for the best effect, with a working window of about 4 hours. A high-fat meal delays absorption. The oral film dissolved on the tongue works after about 30 minutes.
About 25 to 30 percent of men who think sildenafil failed respond after instruction on timing, food and stimulation, roughly 1 in 4, according to clinical guidance. More on this: ED tablets not working.
What dose of sildenafil is used?
The usual starting dose is 50 mg, raised to 100 mg if the effect is not strong enough and the tablet is well tolerated. A lower start is used with some interacting medicines and with an alpha blocker for the prostate. The table lists the key facts.
| Sildenafil | |
|---|---|
| Start dose | 50 mg |
| Maximum dose | 100 mg, once a day at most |
| Taken | About 1 hour before sex |
| Works for | About 4 hours |
| Food | Empty stomach works best; a fatty meal delays it |
How well does sildenafil work?
Sildenafil made 57 percent of intercourse attempts successful against 21 percent on placebo in a meta-analysis of 27 trials with 6,659 men (Archives of Internal Medicine, 2002), close to 3 times as often. Sildenafil also works in men with diabetes and after prostate cancer treatment, best after nerve-sparing surgery.
Sildenafil, tadalafil, vardenafil and avanafil work about equally well, and the choice depends on timing and duration: sildenafil vs tadalafil.
What are the side effects of sildenafil?
The most common side effects of sildenafil are flushing in 12 percent, headache in 11 percent and indigestion in 5 percent, about 1 in 8, 1 in 9 and 1 in 20 men, in a meta-analysis of 14 trials. Nasal congestion is also common. Sildenafil occasionally tints vision blue for 2 to 3 hours.
Rare but serious effects are sudden loss of vision in one eye (non-arteritic anterior ischaemic optic neuropathy, NAION) and sudden hearing loss. Stop sildenafil and seek medical help immediately for a sudden change in vision or hearing.
Sildenafil in Dubai and the UAE
Is sildenafil available without a prescription in Dubai?
No, sildenafil is a prescription-only medicine in Dubai, dispensed by licensed pharmacies, according to the Dubai Health Authority classification. Viagra and generic sildenafil are both available on prescription.
Why not buy sildenafil online?
A regional survey of 1,008 men cited by the UAE expert panel on erectile dysfunction found that 84.1 percent of men using erection tablets had bought them without a prescription, more than 8 in 10, and only 38.1 percent of the users had erectile dysfunction at all (Journal of Multidisciplinary Healthcare, 2025). The UAE Ministry of Health and Prevention has warned against sexual enhancement products that contain undeclared sildenafil, tadalafil or vardenafil, because of the risk of a severe fall in blood pressure (Khaleej Times).
Dr Felix treats within the scope of his Dubai Health Authority licence. When a case needs a specialist view, for example a penile curvature, an abnormal prostate finding or heart disease that limits exertion, the treatment decision is made together with a urologist or cardiologist.
Need a longer window or a daily tablet? Tadalafil (Cialis). Not sure how severe the problem is? take the 1-minute erection check.
Who Is a Good Candidate?
- Men with erectile dysfunction who have sex occasionally and plan it about 1 hour ahead.
- Men with diabetes, high blood pressure or after prostate treatment, once the heart has been assessed.
- Men who prefer the medicine with the longest safety record.
- Men with mild erectile problems and risk factors such as diabetes or high blood pressure.
- Nitrates for chest pain, in any form, including glyceryl trinitrate spray and isosorbide tablets: sildenafil is never combined with them.
- Heart disease that makes sexual activity unsafe, or a recent heart attack or stroke: cardiology assessment first.
- Previous sudden loss of vision (NAION) or retinitis pigmentosa: sildenafil is not used or used only with specialist advice.
- Alpha blockers for the prostate such as doxazosin: a stable dose first and a low starting dose of sildenafil.
What Happens During the Consultation
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1
History
How the problem started, morning erections, desire, relationship, medicines including nitrates and alpha blockers, and the 5-question erection score.
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2
Heart and blood tests
Blood pressure, pulses, cardiovascular risk, and blood sugar, lipids, thyroid and morning testosterone where they fit.
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3
Choice of tablet
Sildenafil or tadalafil by timing, duration and preference, with the starting dose.
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4
Instruction and review
How to take it correctly, what to expect, and a review after 4 to 8 attempts.
Program Structure & Follow-Up
How is treatment with sildenafil followed up?
The first review follows about 4 to 8 attempts on the tablet. The review checks the effect, side effects and the way the tablet was taken; the prescriber may adjust the dose or change treatment after checking tolerance, kidney and liver function, and interactions. A maximum dose is not a required step. A change of 4 points or more on the erectile function score counts as a clinically important improvement.
Cardiovascular risk factors found at the first visit, such as high blood pressure or cholesterol, are followed on their own schedule, because erectile dysfunction often appears before heart disease. Ongoing care: Sexual Health Membership.
Benefits, Limits & Safety
What are the benefits of sildenafil?
Sildenafil restores erections sufficient for intercourse in many men, works across most causes of erectile dysfunction and has the longest safety record of the 4 PDE5 inhibitors.
What are the limits of sildenafil?
Sildenafil needs sexual stimulation, planning about 1 hour ahead and a free window of about 4 hours. It does not raise desire, does not treat premature ejaculation on its own in men without erectile problems, and does not cure the cause. Men with a severe arterial or nerve cause respond less.
When to seek urgent help
Do not combine sildenafil with nitrates, poppers or riociguat. An erection lasting more than four hours needs an emergency department immediately. Stop treatment and seek immediate help for sudden loss of vision or hearing. For current severe chest pain, marked breathlessness or collapse, call 998 in the UAE and tell staff when you last took the medicine; do not wait for a callback.
What the evidence shows
57 percent successful intercourse against 21 percent on placebo in 27 trials with 6,659 men.
How you are followed
Review after 4 to 8 attempts: effect, side effects, correct use, then dose adjustment.
When sildenafil is not used
With nitrates in any form, and with heart disease that makes sex unsafe until a cardiologist has cleared it.
Cost & Program Investment
What treatment with sildenafil costs depends on the brand, the dose and the tests needed at the first visit. Dr Felix explains the figure before any prescription.
Frequently Asked Questions
Sildenafil is taken about 1 hour before sex, on an empty stomach for the best effect. It works for about 4 hours and needs sexual stimulation to produce an erection.
Generic sildenafil contains the same active ingredient as Viagra and is used at the same doses. Both are prescription-only medicines in Dubai.
Sildenafil is usually safe with most blood pressure medicines. It is never combined with nitrates, and with alpha blockers such as doxazosin the alpha blocker dose is stable first and sildenafil starts low.
About 1 in 4 men who think sildenafil failed respond after instruction on timing, food and stimulation. The prescriber then reviews whether a dose adjustment or a different treatment is appropriate. Do not increase the dose yourself.
The cost of sildenafil in Dubai depends on the brand, the dose and the first-visit tests. Dr Felix explains the full cost in the consultation before anything is prescribed.
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.
- Sildenafil for male erectile dysfunction: a systematic review and meta-analysis
- Viagra: European public assessment report
- Erectile Dysfunction: AUA Guideline
- Erectile Dysfunction: Expert Panel Recommendations for Evaluation and Management in the United Arab Emirates
- Don’t consume sexual enhancement pills, warns UAE health ministry
- Drug Control
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.