Sildenafil Tablets Explained: Strengths, Forms and What Is in Them

• Sildenafil tablets 25mg, 50mg and 100mg supplied from a GPhC registered UK pharmacy, registration number 9012878
• Every pack dispensed against a prescription issued after an online consultation with UK registered prescribers
• Pack sizes from 4 tablets to 48 tablets, with the patient information leaflet included in every carton
• Free DPD Next Working Day delivery on orders placed before 3pm Monday to Friday, in plain unbranded outer packaging

Most people who search for sildenafil already know roughly what it does. What is harder to find is a plain description of the tablet itself: what is inside it, why the same medicine appears under two names, what the letters printed after the name on a pack mean, and how to tell a pack licensed for supply in the United Kingdom from one that is not.

This page answers those questions: the strengths available here, the difference between sildenafil and sildenafil citrate, what a film coated tablet is, the full ingredient list, what the abbreviations BP and IP signify, and what the leaflet in the carton contains. Prices quoted are the standard EveryDayMeds website prices at the time of writing. Treatment suitability depends on an individual clinical assessment.

Additionally, this page explains how sildenafil tablets are administered oral dose forms designed to improve erectile function by promoting smooth muscle relaxation and increasing blood flow to the corpus cavernosum. It also touches on interactions with nitric oxide donors such as amyl nitrate and the importance of avoiding illegal drugs and excessive alcohol consumption while on treatment. Information about sildenafil alternatives and considerations for elderly patients is also included to provide a comprehensive overview.

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Key things to know

• Sildenafil and sildenafil citrate are the same medicine. Citrate is the salt form the active ingredient is made into so that it can be pressed into a stable tablet.
• Three strengths are licensed in the UK for erectile dysfunction: 25mg, 50mg and 100mg. Sildenafil 20mg tablets are also licensed for pulmonary arterial hypertension, a different condition, and should not be treated as a lower-strength erectile dysfunction product.
• The strength printed on the pack refers to the amount of sildenafil, not the amount of sildenafil citrate. The salt weight is higher.
• BP refers to the British Pharmacopoeia, the UK's official collection of quality standards for pharmaceutical substances and medicinal products.
• Every legitimate UK pack contains a patient information leaflet. A pack with no leaflet, or a leaflet not written in English, is a warning sign.
• Sildenafil is a prescription only medicine in the UK and cannot be supplied without a prescription issued following a clinical assessment.

What are sildenafil tablets

Sildenafil tablets are a prescription only medicine. Sildenafil belongs to a group of drugs called phosphodiesterase type 5 inhibitors, usually shortened to PDE5 inhibitors, and in the UK it is used to treat erectile dysfunction in men. It is not indicated for use in women. It is also the same active ingredient found in the originator brand, which is why generic sildenafil is often described as the generic version of that product.

The same active ingredient is also authorised, in a different strength and under separate product licences, for the treatment of adults and children aged 1 to 17 years with pulmonary arterial hypertension, a condition affecting blood pressure in the vessels supplying the lungs. The two uses are covered by different marketing authorisations, different strengths and different prescribing routes, which is why a 20mg sildenafil tablet occasionally appears alongside the more familiar strengths.

Sildenafil works by relaxing the smooth muscle in the walls of blood vessels, increasing blood flow to the tissue involved. It does not create a response on its own: physical stimulation is still required for the medicine to have any effect, a point the patient leaflet makes explicitly. It also does not cure erectile dysfunction. It treats the symptom while it is in the body, which is why a healthcare provider will usually want to understand the underlying cause as well as prescribe a treatment.

What a sildenafil tablet physically contains

The active ingredient accounts for a small fraction of the tablet's mass. The rest is made up of excipients: inactive ingredients that give the tablet structure, allow it to be manufactured consistently, help it break apart in the stomach and protect the active ingredient from light and moisture.

Excipients vary between sildenafil manufacturers. Depending on the specific product, the tablet may contain ingredients such as microcrystalline cellulose, calcium hydrogen phosphate, croscarmellose sodium, magnesium stearate, hypromellose, lactose and other coating ingredients. The patient information leaflet supplied with your pack is the authoritative source for its exact ingredient list.

The lactose in the film coat is worth flagging, because people who avoid lactose often assume a tablet is free of it. The amount varies between products and can be small, but anyone with lactose intolerance should check the leaflet for their specific product.

Sildenafil citrate vs sildenafil: two names, one medicine

This is the most common source of confusion, and it has a simple explanation. Sildenafil is the active substance, while sildenafil citrate is the salt form used in the tablet. UK product information states the amount as an equivalent quantity of sildenafil.

Drug molecules in their pure base form are frequently unstable, poorly soluble or difficult to press into a tablet that behaves predictably. Converting the base into a salt solves that. Once the tablet dissolves in the body, the salt separates and the active sildenafil is what circulates and acts.

The practical consequence is the labelling convention. UK product information expresses the strength as sildenafil citrate equivalent to a stated amount of sildenafil. A 50mg tablet therefore contains rather more than 50mg of sildenafil citrate, because the citrate portion adds weight. What the prescriber, the pharmacist and you all care about is the 50mg of sildenafil, and that is the number printed on the carton.

So when comparing sildenafil citrate vs sildenafil as though they were alternatives, there is nothing to compare. They are not two products, two grades or two potencies. Searches such as sildenafil citrate almost always come from someone who has seen one name on the outside of the box and the other inside the leaflet and wants to be certain they have been given the right thing. They have.

Sildenafil citrate molecular formula and what it actually tells you

People search for the sildenafil citrate molecular formula for two reasons: curiosity about the chemistry, or an attempt to verify that a pack they have been sent is genuine.

The first is reasonable. The second does not work. A molecular formula is a laboratory specification that appears in pharmacopoeial monographs used by manufacturers and analytical chemists, not on consumer packaging and not in the patient leaflet. The molecular formula is not normally a consumer-pack authentication check, so it is not a useful way to verify whether a pack is genuine.

What the formula tells you conceptually is that the compound is a two part structure, the sildenafil molecule plus a citric acid component, which is why the citrate weight and the sildenafil weight differ. If you need the precise formula and molecular weight for academic or professional purposes, the authoritative place to obtain it is the relevant pharmacopoeial monograph rather than any consumer facing website, including this one. For authenticating a pack, the checks that do work are set out below.

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Sildenafil tablets strengths available in the UK

Three strengths are licensed and supplied here for erectile dysfunction.

Sildenafil tablets 25mg

Sildenafil tablets 25mg is the smallest of the three licensed strengths. It exists because sensitivity to PDE5 inhibitors varies considerably between individuals, and because certain circumstances make a smaller amount the appropriate starting point in a prescriber's judgement. It is dispensed in the same pack sizes as the other strengths.

Sildenafil tablets 50mg

Sildenafil tablets 50mg is the recommended starting dose for many adults with erectile dysfunction. Depending on efficacy and tolerability, the dose may be reduced to 25mg or increased to 100mg.

Sildenafil tablets 100mg

Sildenafil tablets 100mg is the largest licensed strength for this indication. A larger strength does not automatically mean a better outcome, and it carries a different side effect profile. Your prescriber will determine the appropriate treatment.

Why a 20mg tablet also exists

A 20mg sildenafil film coated tablet is separately licensed in the UK, and it is not a smaller version of the erectile dysfunction product. It belongs to the pulmonary arterial hypertension indication described earlier, is prescribed by a different route and is taken on a completely different pattern. If you encounter a 20mg pack in a listing, it is not an economical alternative to the 25mg tablet. It is a different treatment for a different condition.

Strength comparison at a glance

The list of sildenafil tablets strengths available in the UK is limited to these. Any strength outside this set, such as 120mg, 150mg or 200mg, does not correspond to a UK licensed sildenafil product for erectile dysfunction, and its appearance in a listing is a strong signal that the supply route is not a licensed one.

Sildenafil film coated tablets: what the coating is for

Many UK-authorised sildenafil products for erectile dysfunction are supplied as film-coated tablets, although other oral sildenafil formulations also exist. The phrase describes a manufacturing step rather than a special formulation: after the core is compressed, a thin polymer film is sprayed onto it.

The coating does several jobs at once. It creates a smooth surface that is easier to swallow, masks the taste of the active ingredient, provides a barrier against moisture and light, carries the colour that identifies the product and gives a surface that can be embossed with strength markings. It is not a modified release mechanism: it dissolves quickly and does not slow absorption meaningfully, so there is no benefit in removing or scraping it.

What sildenafil tablets look like

One UK-authorised sildenafil product described in MHRA documentation is a blue, rounded diamond-shaped film-coated tablet supplied in PVC/aluminium blisters. Tablet appearance and pack sizes vary between manufacturers.

Generic sildenafil products are not required to look identical to one another. Manufacturers use different shapes, sizes, embossing and shades of blue, so a change of appearance between one dispensing and the next usually means the pharmacy has been supplied by a different licensed manufacturer rather than that anything is wrong.

What should stay consistent is the information: the strength, the words "film coated tablets", the name of the marketing authorisation holder, a marketing authorisation number, a batch number, an expiry date and an enclosed leaflet in English. Those are the details worth reading, not the shade of the tablet.

Sildenafil tablets are a potent and selective inhibitor of the enzyme phosphodiesterase type-5 (PDE5), which plays a key role in regulating blood flow. This selective inhibitor mechanism helps sildenafil improve erectile function by enhancing blood flow to the penis during stimulation. Sildenafil treatment requires sexual stimulation to be effective and does not cause an erection spontaneously.

Patients are advised to follow the usual dose prescribed by their healthcare provider, often starting with a starting dose of 50mg. Sildenafil dosages can be adjusted to 25mg or 100mg depending on individual response and tolerability. It is important not to exceed one tablet in a 24-hour period to avoid adverse events.

Avoiding concomitant use with certain medications such as HIV protease inhibitors is critical due to potential interactions. Additionally, patients should not use sildenafil alongside nitrates or decongestant nasal spray containing amyl nitrate, as this can cause dangerous drops in blood pressure.

Clinical trials have demonstrated the efficacy of sildenafil in improving erectile function and its safety profile when used as directed. However, users should be aware of possible side effects, including vision loss and other visual disturbances, which are rare but serious adverse events.

Patients are also advised to avoid drinking alcohol excessively while using sildenafil, as alcohol can reduce effectiveness and increase the risk of side effects.

When considering treatment options, sildenafil is often compared with generic Viagra and other PDE5 inhibitors like tadalafil and vardenafil. Tadalafil, for example, has a longer duration of action, lasting up to 36 hours, providing an alternative for those seeking extended effects.

To obtain sildenafil in the UK, patients must submit delivery requests through a registered pharmacy after a clinical assessment. Sildenafil is not available over the counter but can be prescribed and delivered discreetly, ensuring privacy and convenience.

It is important to note that sildenafil does not protect against sexually transmitted diseases, so appropriate preventive measures should still be taken.

Overall, sildenafil tablets offer an effective treatment for erectile dysfunction when used responsibly under medical supervision, with attention to contraindications, drug interactions, and lifestyle factors such as alcohol consumption.

The full ingredient list in one place

Excipients vary slightly between manufacturers. The leaflet inside your specific pack is the authoritative list for that product, and it is the one to check if you have a known intolerance.

Sildenafil tablets BP and sildenafil tablets IP: what the letters mean

Two abbreviations turn up constantly in listings, and they are not interchangeable.

Sildenafil tablets BP

BP stands for British Pharmacopoeia, the collection of quality standards for medicinal substances that applies in the United Kingdom, published under the authority of the medicines regulator. A product described as sildenafil tablets BP is claiming to meet the British standard for identity, purity and performance.

In practice, UK cartons more often carry the plain product name, the strength and the words "film coated tablets" rather than a BP suffix, because a UK marketing authorisation already requires the applicable standard to be met. Seeing BP is not a problem. Not seeing it is not a problem either. The marketing authorisation number is the meaningful marker.

Sildenafil tablets IP

IP refers to the Indian Pharmacopoeia. The presence of an IP designation does not itself establish that a medicine has a UK marketing authorisation. If you are checking a medicine for UK-authorised supply, verify the product and licence through the MHRA medicines database rather than relying on BP or IP wording alone.

This matters because the searches for sildenafil tablets ip and sildenafil citrate tablets ip 100mg are common among UK buyers, and almost all of the listings returned are for products holding no UK marketing authorisation.

The implications are worth stating plainly. A product without the appropriate UK marketing authorisation is not authorised for routine UK supply. Buying medicines through an unregulated route also means you cannot rely on the normal UK regulatory and pharmacy safeguards.

This is not theoretical. UK enforcement activity in 2023 alone accounted for more than 15.5 million doses of falsified and unlicensed medicines seized, with a street value above £30 million, more than 12,000 websites disrupted and around 3,000 social media profiles closed. Falsified and unlicensed lifestyle products, including erectile dysfunction medication, were specifically identified within that activity. A later period running from December 2024 to May 2025 accounted for a further 7.7 million doses valued at £17.2 million, with 367 websites and accounts removed.

If you suspect you have bought a fake medicine, do not take it.

How to check a pack is licensed for UK supply

The checks that genuinely work are unglamorous and take about a minute.

1. Look for a marketing authorisation number on the carton, usually formatted as PL followed by digits. Licensed UK sildenafil products for erectile dysfunction are held as 25mg, 50mg and 100mg film coated tablets, and the regulator maintains a searchable products database listing them.
2. Confirm there is a patient information leaflet inside the carton, written in English, matching the strength on the box.
3. Check that the supplying pharmacy holds a GPhC registration and that the details displayed match the register entry. The register is searchable by the public, and registration is renewed annually.
4. Check that a prescription was actually issued after an assessment. A supply route that asks no clinical questions is not operating as a UK pharmacy should.
5. Read the carton for a batch number and an expiry date. Their absence is a serious warning sign.

EveryDayMeds operates as OVIO Ltd trading as EveryDayMeds, GPhC registration number 9012878, from 109 Coleman Road, Leicester, LE5 4LE.

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Sildenafil tablets pack of 4, pack of 8 and larger quantities

Pack size affects the cost per tablet, and the relationship is not linear. A sildenafil tablet pack of 4 is the smallest quantity supplied and is often chosen by people at the start of treatment. A sildenafil tablets pack of 8 is the next step up, and it is the largest quantity documented for the reclassified product referenced earlier. Larger quantities are supplied against a prescription. The table below sets out standard EveryDayMeds website prices.

Sildenafil tablets patient information leaflet: what is inside it

Every licensed pack contains a patient information leaflet, and it is a regulated document rather than marketing material, which is why leaflets from different manufacturers read so similarly.

A sildenafil tablets patient information leaflet covers, in a fixed order: what the medicine is and what it is used for, what you need to know before you take it, including the contraindication list, warnings and interactions, how to take it, possible side effects, how to store it, and the contents of the pack together with other information, which is where the excipient list sits.

The contraindication section is the part most worth reading properly. The leaflet distinguishes between situations where sildenafil must not be taken and conditions that should be discussed with a doctor before treatment. Important contraindications include taking nitrates or nitric oxide donors such as amyl nitrite, taking riociguat, certain previous vision-loss conditions, severe liver problems and very low blood pressure. Conditions such as Peyronie's disease, stomach ulcers, bleeding disorders, sickle cell anaemia, leukaemia and multiple myeloma are among the conditions that should be discussed with a healthcare professional rather than being presented as universal contraindications.

The leaflet also describes what an allergic reaction looks like, instructs you to seek urgent help if one occurs, and advises a check up within the first six months of starting treatment. Keep the leaflet rather than discarding it with the outer packaging, because it is the reference you will want if a question arises later.

Warnings the leaflet asks you to act on

Seek emergency medical care for a painful erection that lasts more than four hours, for a sudden decrease or loss of vision in one or both eyes, for chest pain, or for signs of an allergic reaction. In each of those situations the leaflet tells you to contact a doctor immediately rather than wait, and immediate medical help is the correct response.

Tell your prescriber about other medicines and other medications you take, including anything for high blood pressure or for low blood pressure, and about medical conditions affecting the heart such as heart disease, heart failure, a recent heart attack or an irregular heartbeat. Liver disease, a curved penis and other health conditions listed in the leaflet also need to be declared. If you think you have taken too much sildenafil, seek medical advice straight away.

Sildenafil tablets how to take them

The pattern for taking sildenafil tablets is set by your prescriber and stated in the leaflet supplied with your pack. What follows is the general handling and timing information documented for the medicine, which helps explain why experiences differ.

A film-coated tablet should be taken as directed in the patient information leaflet. Some sildenafil tablets are designed to be divided, while others are not, so do not split a tablet unless the specific product information or your prescriber/pharmacist says it can be divided.

Documented figures put peak concentrations between 30 and 120 minutes after taking a tablet on an empty stomach, with a median around 60 minutes, and describe an onset in the 30 to 60 minute range. The terminal half life is documented as 3 to 5 hours. A meal delays absorption by roughly 60 minutes and a high fat meal produces the greatest delay, which is a frequent explanation for a tablet appearing not to have worked when it was still being absorbed. Grapefruit and grapefruit juice should be avoided.

Sildenafil for erectile dysfunction is not taken on a regular dosing schedule, so there is no missed dose to make up and no next dose to bring forward. The prescribed dose is taken as required, within one absolute limit that appears in the leaflet for every licensed product: never take more than one tablet in any 24 hour period, and never take a second tablet because the first did not appear to work. If a tablet does not produce the expected result, that is a conversation to have with your prescriber, not a reason to take more. This medicine should only be used under the supervision of an appropriately qualified prescriber. Results vary between individuals.

Side effects documented for sildenafil tablets

Headache is documented as very common, meaning it may affect more than 1 in 10 people. Effects documented as common include nausea, indigestion and stomach discomfort, a stuffy nose, dizziness, facial flushing, hot flush, a colour tinge to vision, blurred vision and other visual disturbance, the visual effects being a recognised class effect rather than a sign that something has gone wrong. Serious side effects are uncommon but are set out in the leaflet, and the side effects of sildenafil should be discussed with a healthcare professional if they persist. Report any side effect that concerns you to your prescriber or pharmacist, and seek urgent medical attention for signs of an allergic reaction, chest pain, or an erection that is painful or lasts more than four hours.

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How sildenafil tablets are supplied in the UK

Sildenafil is not available over the counter in the UK. It can only be obtained with a valid prescription issued by an authorised health professional, because the medicine carries a substantial interaction and contraindication list. That does not require a face to face appointment. UK guidance for distance selling is specific: prescribing decisions must not be based on the information provided in a questionnaire alone, the person's identity must be checked, and there should always be a means of having two way communication between the person and the prescriber for all online prescribing.

At EveryDayMeds the route is an online consultation with UK registered prescribers, followed by dispensing from a GPhC registered pharmacy. You can view the sildenafil tablets listing for strengths, pack sizes and current pricing, or browse the full erectile dysfunction treatments range. The branded Viagra tablets option is available for anyone who prefers the originator product.

Orders placed before 3pm Monday to Friday are dispatched for DPD Next Working Day delivery at no charge, with a signature required on arrival. A Saturday option is available at £14.99 with a 3pm Friday cut off. There is no dispatch on Saturdays, Sundays or English public and bank holidays. Everything is sent in plain unbranded outer packaging with tamper evident seals.

Medical Disclaimer

This page is for general information only and does not constitute medical advice. It does not replace a consultation with a qualified healthcare professional and should not be used to diagnose or treat any condition. Sildenafil is a prescription only medicine. This medicine should only be used under the supervision of an appropriately qualified prescriber. Treatment suitability depends on an individual clinical assessment. Your prescriber will determine the appropriate treatment. Results vary between individuals. Always read the patient information leaflet supplied with your medicine before use, and speak to your prescriber or pharmacist if you have questions about your treatment, other medicines you take, or any symptom that concerns you. Seek urgent medical attention if you experience signs of an allergic reaction, chest pain, or an erection that is painful or lasts more than four hours. Prices and delivery terms stated were correct at the