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Sildenafil is a treatment for adult men with erectile dysfunction, sometimes known as impotence.
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Sildenafil is licensed in the UK in three strengths. The 50mg strength is available as a pharmacy medicine (Viagra Connect) without a prescription, following a pharmacist consultation. The 25mg and 100mg strengths are prescription-only medicines, available through Access Doctor after an online consultation with a UK-registered prescriber, who will confirm sildenafil is suitable for you and which strength applies.
Do not take sildenafil if you take any nitrate medicine for chest pain, or if you use poppers. The combination can be fatal.
Do not take more than one tablet in 24 hours.
The recommended starting dose for most men is 50mg, taken approximately one hour before sexual activity.
If you have an erection lasting more than 4 hours, seek emergency medical help immediately.
If you experience sudden vision loss or hearing loss, stop taking sildenafil and seek medical help.
If you are taking alpha‑blockers for prostate problems or high blood pressure, tell your doctor – you may need a lower starting dose (25mg).
Access Doctor's prescriber-led consultation covers the 25mg , 50mg and 100mg strengths. If your consultation confirms you're suitable, your prescription is issued by a UK-registered prescriber and dispatched from our GPhC-registered pharmacy in discreet, plain packaging.
This information is for educational purposes and does not replace the advice of your doctor or pharmacist. Always read the patient information leaflet inside the pack. If you are unsure about any aspect of your treatment, speak to a healthcare professional.
Sildenafil is a medicine that contains the active ingredient sildenafil citrate, which is identical to the ingredient in the branded medicine Viagra. It belongs to a class of drugs called PDE5 inhibitors, which work by relaxing the blood vessels in your penis. When you become sexually aroused, this allows more blood to flow into the penis, helping you get and keep an erection that is firm enough for satisfactory sexual activity. A very important point: sildenafil only works if you are sexually stimulated. It is not an aphrodisiac, it will not increase your sexual desire, and it will not produce an erection on its own. Without sexual arousal, the medicine will not work. Erectile dysfunction (ED) affects at least one in ten men at some point in their lives. It can be caused by physical factors such as diabetes, high blood pressure, high cholesterol, heart disease, or by psychological factors such as stress or anxiety. Before starting any treatment, it is always wise to speak to a doctor or pharmacist to understand the underlying cause of your symptoms.
Sildenafil tablets are available in three different strengths: 25mg, 50mg and 100mg. 50mg tablets – This is the standard starting dose for most men. It is the dose that doctors usually recommend first because it works well for the majority of people while keeping side effects manageable. 25mg tablets – This is a lower dose, used for men who may need to start with a milder option. It is often prescribed for men aged 65 and over, those with liver or kidney problems, or those who experience side effects from the 50mg dose. 100mg tablets – This is the maximum strength. It is used for men who have tried 50mg and found that it does not work well enough, but who tolerate the medicine without troublesome side effects. How do you know if your dose is right? If 50mg works well for you, stick with it. If 50mg works but not quite well enough, and you have no troubling side effects, your doctor may suggest increasing to 100mg. If 50mg gives you side effects such as bad headaches or flushing, your doctor may suggest reducing to 25mg. If 50mg does not work at all after several attempts, speak to your doctor. You may need a different ED treatment such as tadalafil or vardenafil. You should never change your dose on your own. Always speak to a doctor or pharmacist first.
To get the best results from sildenafil, you need to use the medicine correctly. When to take it – Take one tablet approximately 60 minutes before you plan to have sex. However, you can take it anywhere from 30 minutes to 4 hours beforehand. How to take it – Swallow the tablet whole with a glass of water. Do not crush or chew the tablet. With or without food – You can take sildenafil with or without food, but a heavy or fatty meal can delay the medicine from being absorbed. For the best results, take it on an empty stomach or after a light meal. How often can you take it? – You should take no more than one tablet in any 24-hour period. The maximum recommended dosing frequency is once per day. Taking more than one will not make it work better, but it will increase your risk of side effects. Sexual stimulation is essential – Sildenafil only works when you are sexually aroused. You and your partner will still need to engage in foreplay. The medicine simply helps your body respond more easily when you are turned on.
The cost of prescription sildenafil depends on strength and pack size. As a guide: sildenafil 100mg (8 tablets) typically costs around £22.99, and sildenafil 25mg (8 tablets) around £16.99; larger packs are typically cheaper per tablet. To access the 25mg or 100mg strengths, complete a short online consultation. A UK-registered prescriber reviews your answers, and if sildenafil is appropriate for you, our GPhC-registered pharmacy issues your prescription and dispatches it in discreet, plain packaging. The 50mg strength is also available without a prescription, under the brand name Viagra Connect, following a pharmacist consultation — see the Viagra Connect page for details. Only obtain sildenafil from a GPhC-registered pharmacy. Unregulated sellers may supply counterfeit medicines that can be dangerous.
If you order sildenafil online through a regulated service like Access Doctor, and you complete the consultation before the daily cut-off time (usually mid-afternoon), your order will be dispatched the same day. Most UK online pharmacies offer sildenafil next day delivery as a standard service, with orders arriving by Royal Mail Tracked 24 or a similar courier service. The packaging is discreet – plain and unmarked – so no one else knows what is inside. Once your order is dispatched, you will receive tracking information so you can follow your delivery all the way to your door. Many pharmacies offer free delivery on orders over a certain amount, and some also provide click-and-collect options allowing you to pick up your order from a local pharmacy in as little as 2 hours after approval.
Most men tolerate sildenafil well, but like all medicines, side effects can occur. Most side effects are mild to moderate and short-lasting. Common side effects (may affect up to 1 in 10 men): Headache – reported in about 12% of users Flushing – redness and warmth of your face and neck, reported in about 10% of users Indigestion – affects about 7% of users Altered vision – usually a blue tinge to your vision, with dizziness, can occur in about 3% of users. If dizziness occurs, it is advisable not to drive or operate machinery Nasal congestion – a stuffy or runny nose Back pain or muscle aches – some men experience aching in their muscles, particularly with the 100mg strength Serious side effects – rare but you need to know about them: Priapism – a painful erection that will not go away. If you have an erection that lasts more than 4 hours, you must seek emergency medical attention immediately. If left untreated, priapism can cause permanent damage to your penis and lead to long-term erectile dysfunction. Sudden vision loss in one or both eyes – this can be a sign of a rare but serious condition. If this happens, stop taking sildenafil and seek medical help urgently. Sudden hearing loss – some men have reported a sudden decrease or loss of hearing, sometimes accompanied by ringing in the ears (tinnitus) or dizziness. Chest pains – this occurs uncommonly (affects up to 1 in 100 men). If chest pains occur, seek medical attention immediately. When to seek medical help: If you develop an erection lasting more than 4 hours If you lose your vision suddenly If you develop chest pain, severe dizziness or nausea during sexual activity – stop sexual activity immediately and seek medical attention If you develop sudden hearing loss or ringing in your ears
There are several groups of men who must not take sildenafil. This is very important. Do NOT take sildenafil if: You take any medicine called a nitrate. Nitrates are prescribed for chest pain (angina). Common nitrate medicines include glyceryl trinitrate (GTN), isosorbide mononitrate, isosorbide dinitrate, and amyl nitrite ("poppers"). Taking sildenafil with a nitrate can cause your blood pressure to drop suddenly and dangerously, leading to fainting, heart attack, or even death. You take a medicine called riociguat (Adempas). This is used to treat high blood pressure in the lungs. You have been advised by a doctor to avoid sexual activity because of a heart problem – such as unstable angina, severe heart failure, or a recent heart attack or stroke. You have low blood pressure (hypotension) or high blood pressure not controlled by medicines. You have a rare inherited eye disease – such as retinitis pigmentosa. You have a physical deformity of the penis – such as Peyronie's disease. This condition increases the risk of priapism. You have a blood disorder – such as sickle cell anaemia, multiple myeloma or leukaemia. These also increase the risk of priapism. You have a stomach ulcer or a bleeding problem such as haemophilia. You are allergic to sildenafil or any of the other ingredients in the tablet.
Yes, it is very important to be aware of potential interactions. Dangerous interactions (do not take sildenafil at all): Nitrates – as described above. This is absolute. Poppers (amyl nitrite) – also absolute. Riociguat (Adempas) – also absolute. Interactions that need caution (tell your doctor before starting sildenafil): Alpha-blockers – medicines such as doxazosin, tamsulosin, terazosin, alfuzosin, and silodosin. These are often prescribed for high blood pressure or for prostate problems. If you take an alpha-blocker, your doctor will start you on the lowest dose (25mg). Ritonavir – an HIV medicine that can increase sildenafil levels. If you take ritonavir, the recommended maximum dose is 25mg within a 48-hour period. CYP3A4 inhibitors – certain antifungals (itraconazole, ketoconazole), certain antibiotics (erythromycin, clarithromycin) and some HIV medicines. Your doctor may advise a lower starting dose. What about alcohol? Sildenafil can work with moderate alcohol consumption, but heavy drinking increases the risk of side effects and may reduce the medication's effectiveness. Both sildenafil and alcohol lower blood pressure, which can lead to dizziness or lightheadedness when combined. Moderate drinking (one or two units) is generally fine, but excessive alcohol can independently impair your ability to get an erection and may make you feel more dizzy. What about grapefruit juice? You should avoid grapefruit juice while taking sildenafil, as it can affect the way the medicine works and may increase the level of sildenafil in your blood.
You need to be careful. You should discuss sildenafil with your doctor or pharmacist if you have any of the following: Heart problems – such as a recent heart attack (within the last 6 months), unstable angina, or severe heart failure. High blood pressure that is not well controlled or low blood pressure. A stroke within the last 6 months. Liver problems – if you have liver impairment (such as cirrhosis), a 25mg starting dose should be considered. Severe kidney problems – if you have severe renal impairment, a 25mg starting dose should be considered. A deformed penis – such as Peyronie's disease. Blood disorders – sickle cell anaemia, leukaemia, multiple myeloma. A stomach ulcer – sildenafil can sometimes aggravate an existing ulcer. A bleeding disorder – such as haemophilia. If you have any of these conditions, you may still be able to take sildenafil, but your doctor will need to start you on a lower dose (25mg) and monitor you carefully.
Store below 25°C (room temperature) in a dry place, away from direct sunlight and heat. Keep the blister pack or bottle in its outer carton to protect it from moisture. Keep the medicine out of the sight and reach of children. Do not use the tablets after the expiry date printed on the packaging. The active ingredient becomes less effective over time. If you have any leftover tablets, do not throw them away in household waste or pour them down the sink. Take them to your local pharmacy, where they will be disposed of safely.
Sildenafil at Access Doctor starts from £8.99, with the price depending on the strength (25mg, 50mg or 100mg) and pack size you're prescribed. Larger packs cost less per tablet. Every price includes your online consultation, your prescription from a UK-registered prescriber, and discreet delivery — there are no separate prescription fees. Generic sildenafil is considerably cheaper than branded Viagra because the patent on the original medicine has expired, and several manufacturers now produce it. The active ingredient, sildenafil citrate, is identical.
The lowest per-tablet price comes from the largest pack of the lowest strength that's clinically appropriate for you — at Access Doctor that's £1.81 per tablet for 25mg in a 16-tablet pack. However, the cheapest option is not automatically the right one: your prescriber will recommend a strength based on your consultation answers, and taking a lower strength than you need simply means the treatment doesn't work. If cost is a concern, ask about larger pack sizes rather than lower strengths. A 16-tablet pack typically works out cheaper per tablet than a 4-tablet pack of the same strength.
Sildenafil 100mg costs £22.999 for a pack of 8 tablets at Access Doctor, working out at £2.87 per tablet. Larger packs reduce the per-tablet cost. 100mg is the maximum licensed strength and is prescription-only — it's normally prescribed for men who have tried 50mg and found it insufficient, but who tolerate the medicine without troublesome side effects. You cannot choose 100mg yourself. A UK-registered prescriber will confirm whether it's appropriate based on your consultation.
Sildenafil 25mg starts at £8.99 for 4 tablets and 50mg costs £9.99. 50mg is the standard starting dose for most men. 25mg is a lower dose typically prescribed for men aged 65 and over, those with liver or kidney problems, those taking alpha-blockers, or anyone who experiences side effects at 50mg.
Yes. The price shown covers your online consultation, review by a UK-registered prescriber, your prescription, and dispensing from our GPhC-registered pharmacy (No. 9011198). There is no separate consultation fee, prescription charge, or subscription. Delivery is free on orders over £40; below that, delivery costs £3.49
Yes. The per-tablet price falls as pack size increases, a 16-tablet pack is cheaper per tablet than a 4-tablet pack of the same strength. If sildenafil already works well for you at a settled dose, a larger pack is usually the more economical choice. If you're trying sildenafil for the first time, a smaller pack lets you check how you respond before committing to a larger quantity.
Prices for generic sildenafil vary between UK online pharmacies, and it's worth checking what each price actually includes. Some services quote a low per-tablet figure but add a separate consultation or prescription fee, or charge a recurring subscription. Others quote a headline price that applies only to the largest pack of the lowest strength. When comparing, check four things: the total price for the pack you'd actually be prescribed, whether the consultation and prescription are included, whether delivery is extra, and whether the pharmacy is registered with the General Pharmaceutical Council. The GPhC maintains a public register you can search, and every legitimate UK online pharmacy displays its registration number.
Sildenafil sold well below the typical UK range, or sold without any consultation at all, is a strong indicator of an unregulated seller. Counterfeit ED medicines are among the most commonly seized fake medicines in the UK, and have been found to contain incorrect doses, no active ingredient, or undeclared substances. A legitimate UK pharmacy will always require a consultation before supplying prescription-only sildenafil (25mg and 100mg), will display a GPhC registration number, and will name its superintendent pharmacist. Access Doctor is registered pharmacy No. 9011198, with Mr Nur Choudhury MRPharmS (GPhC 2058287) as superintendent pharmacist.
Sildenafil is available on the NHS for men with certain medical conditions, including diabetes, multiple sclerosis, Parkinson's disease, prostate cancer, spinal injury, and some others. If you qualify, you'll pay the standard NHS prescription charge, which may be less than the private price depending on the pack size you need. If you're exempt from prescription charges, it's free. If you don't meet the NHS eligibility criteria, your GP can still issue a private prescription, which you'd pay for in full. An online pharmacy consultation is an alternative route for men who don't qualify on the NHS or would prefer not to discuss it with their GP.
No. There are no consultation fees, prescription charges, subscription costs, or hidden extras. Delivery is free on orders over £40, and £3.49below that. Repeat prescriptions are issued free of charge, and you can stop ordering at any time without notice or cancellation fees.
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