Sildenafil

Sildenafil will remain in the blood for longer than 4 hours but usually at concentrations too low to be effective (see graph below). If effects last longer than 4 hours it is usually because the dosage taken is higher than required, with the drug remaining effective in the blood for longer. Taking sildenafil shortly after eating a meal, particularly a meal high in fat, can delay the effects. It is advised to use the lowest effective dose which will reduce possible side effects.

For further information read How long does sildenafil last?

In some cases ED is associated with high blood pressure or cholesterol, poor circulation, obesity, lack of exercise, smoking, and diabetes, and these are also risk factors for heart disease and stroke. Men with ED need to be examined and tested before starting treatment. It is fine to obtain repeat supplies of sildenafil online, but this does not replace a face-to-face visit to a doctor.

Most men do not seek medical help for their ED because of embarrassment or social stigma that may lead some men to self-treat.

Before ordering sildenafil online men must first read medical information about erectile dysfunction and answer medical questions to check for eligibility. Our doctors will then review your information before prescribing, and are available to answer any questions you may have.

Studies suggest that men are capable of using written sildenafil patient education materials to accurately assess their suitability for treatment with 50mg sildenafil.

Medically they are the same. Viagra is Pfizer's brand name for sildenafil. Sildenafil is the medical name for the active ingredient in both. Sildenafil and Viagra both come in packs of 4 and 8 tablets in strengths of 25mg, 50mg, and 100mg. They are interchangeable.

No, they are medically identical. They are equally effective and have the same side effects and other features.

All three are from the same class of medicine (PDE5 inhibitors) and work in the same way. They are all equally effective, but have different durations of action. Sildenafil stays active for about 4 hours, Levitra for 4-5 hours and Cialis for 36 hours. Sildenafil is most suitable for men intending to be sexually active within a few hours of taking a tablet, after which time the effects will wear off.

Sildenafil is relatively cheap to produce and is supplied by a number of competing drug companies. This lowers prices. Viagra, which is simply Pfizer's brand of sildenafil, is supplied by Pfizer alone. Pfizer have chosen to keep the price of Viagra higher and can still find a market as some men are loyal to the Viagra brand.

Sildenafil is a medicine for which the patent has expired. This means the pharmaceutical company which developed it, Pfizer, cannot prevent other companies producing it. There is a big demand, and over a dozen pharmaceutical companies produce and market their own sildenafil. The following are UK licensed manufacturer brands: Accord, Actavis, Amarox, Bristol Labs, Crescent, Dr Reddys, Genesis, Milpharm, Mylan, Teva, RxFarma, Sandoz, Somex, Zentiva, Pfizer. Only buy from registered pharmacies to guarantee tablets meet standards.

If you obtain sildenafil from UK regulated websites and pharmacies there will be no difference. The active ingredient in one 25mg tablet of any brand of UK licensed sildenafil will be the same as any other. The appearance, shape, and colour may vary, but the active ingredient will be the same. Men often have a preference for one brand over another, but usually find that when their preferred brand is not available, they are just as happy with the alternative. See generic sildenafil brand preference survey report and brands of sildenafil pages for further information.

Yes. Since April 2018 pharmacies can supply Viagra Connect (sildenafil 50mg) without a prescription, although this is significantly more expensive. Lower cost generic sildenafil 50mg is also now available over the counter without a prescription. Original Viagra and some other generic sildenafil remain a prescription only medicine which can be dispensed legally only from registered pharmacies. UK online pharmacies use electronic prescriptions issued by doctors or specialist pharmacists. When you order medicine from Dr Fox a prescription is issued electronically to our licensed pharmacy, so you do not need a paper prescription from your own doctor. Use only registered pharmacies, as unregulated suppliers are not subject to controls and will be selling fake medicine which may be ineffective and possibly dangerous.

Yes, GPs can prescribe sildenafil, but usually do so in only limited amounts in line with strict eligibility criteria. NHS prescription fees will apply. In some cases it will cost less to buy sildenafil online than obtaining it repeatedly through the NHS where the prescription fees may be higher. See Sildenafil on the NHS page.

Some brands of sildenafil tablets are scored to enable them to be cut or broken in two easily. Other brands are un-scored and can be difficult to split without crumbling. Purchasing a pill-splitter can help the process.

It is best not to drink alcohol when taking sildenafil or to drink only a small amount (one or two units). Alcohol is a depressant and tends to reduce erections and will reduce the effectiveness of treatment. Some side effects of sildenafil are likely to increase with alcohol, particularly low blood pressure.

Sildenafil is usually effective and usually remains effective at the same dose over many years. The body does not get used to sildenafil or become immune to its effects. If there is a poor response from time to time, this is to be expected, as the circumstance around taking the tablets may not be right every time. If this happens, you should try again with the same strength tablets and can expect the same good responses as you had previously. If your usual sildenafil repeatedly fails to help, you should consult your regular doctor to see if there has been a change in the underlying cause of your ED or to see if another type of treatment might be more suitable. See My ED medicine is not working page.

No, the combination of ED tablets is potentially dangerous and can cause toxic effects of overdose. If one type of tablet does not work, its strength can be increased or an alternative type of tablet can be tried, but treatments must not be combined. Leave at least 24 hours between sildenafil and Levitra and other treatments.

Sildenafil can be taken with most other prescription medicines, with some notable exceptions. Nitrates used mainly to treat heart disease and angina can interact and cause a dangerous fall in blood pressure. For a full list of interacting medicines check the patient information leaflet supplied with the tablets. Checks for interactions are carried out in online consolations.