For erectile dysfunction, the usual sildenafil dosage for many adults is 50mg taken when needed, approximately one hour before sexual activity. A prescriber may reduce the dose to 25mg or increase it to 100mg according to effectiveness, side effects, health conditions and other medicines. The maximum recommended dose is 100mg, and sildenafil should not normally be taken more than once in a day.
That summary is general information rather than a personal dosing instruction. The right sildenafil dosage must be confirmed through an appropriate assessment, because a higher strength is not automatically better and a lower strength can still cause side effects. Sildenafil also requires sexual stimulation; it does not create an automatic erection.
Eligible adults can review Sildenafil treatment options and complete a confidential online assessment. A prescriber reviews the information before deciding whether treatment is suitable and which strength may be appropriate.
Current NHS guidance and UK product information describe 50mg as the usual dose for erectile dysfunction. It is taken as needed rather than on a fixed daily schedule for most people. Depending on response and tolerability, the dose may be decreased to 25mg or increased to 100mg.
The aim is not to reach the highest dose. The aim is to find the lowest suitable sildenafil dosage that provides an adequate response without unacceptable side effects. Someone who responds well to 25mg does not gain an automatic benefit from moving to 50mg or 100mg.
The 25mg, 50mg and 100mg strengths contain the same active ingredient. They differ in the amount of sildenafil in each tablet. They are not separate medicines, and the strength should not be selected by price, another person’s experience or the assumption that more medicine must work better.
Sildenafil 25mg is the lowest commonly used tablet strength for erectile dysfunction. It may be considered when a lower starting dose is clinically appropriate, when side effects occur at a higher dose, or when another health condition or interacting medicine can increase sildenafil exposure.
UK product information states that a 25mg starting dose may be considered for people with severe renal impairment or hepatic impairment. It may also be considered with certain medicines that inhibit CYP3A4 or when a person is established on alpha-blocker treatment. These decisions require professional assessment because the interaction, the other medicine and the person’s blood pressure all matter.
A lower sildenafil dosage is not guaranteed to be free from side effects, and it may not provide enough benefit for everyone. Do not increase from 25mg by taking extra tablets or combining strengths unless a prescriber has specifically advised the change.
The dedicated Sildenafil 25mg guide explains the lower strength in more detail without replacing an individual prescribing decision.
Sildenafil 50mg is the usual recommended dose for many adults using the medicine for erectile dysfunction. It provides a practical starting point from which response and tolerability can be assessed.
A 50mg sildenafil dosage may be appropriate when there is no reason to start lower and no previous evidence that a higher dose is needed. It should still be used exactly as directed. The fact that 50mg is a common starting dose does not mean it is suitable for every person.
If 50mg provides an adequate erection during sexual stimulation and side effects are manageable, there may be no clinical reason to increase the dose. If it causes troublesome effects, a lower strength or a different treatment may be considered. If it is repeatedly ineffective despite correct use, a prescriber can review timing, health factors and whether a dose change is appropriate.
Read the Sildenafil 50mg guide for focused information about the standard strength, its use and the questions to discuss during review.
Sildenafil 100mg is the maximum recommended dose for erectile dysfunction. It may be considered when a lower dose has not produced an adequate response and the higher dose is clinically suitable.
The 100mg strength should not normally be used as an automatic first choice. Increasing the sildenafil dosage can increase medicine exposure and may make adverse effects more likely or more noticeable. Common unwanted effects can include headache, flushing, indigestion, nasal congestion, dizziness and visual disturbance.
Sildenafil 100mg does not reliably work faster or last longer than 50mg. Strength and duration are different questions. A higher dose may improve the erectile response for some people, but the timing guidance and once-daily maximum frequency still apply.
The Sildenafil 100mg guide explains when the highest standard strength may be considered and why professional review is important.
For erectile dysfunction, sildenafil is usually taken approximately 30 to 60 minutes before sexual activity. NHS guidance says it may be taken up to four hours before sex. Follow the timing on the dispensing label or the instructions given by the prescriber or pharmacist.
Swallow the tablet with water. Sexual stimulation is required for it to support an erection. Taking a tablet without arousal does not mean the medicine has failed.
A safe sildenafil dosage routine should include these safety limits:
The guide to the best time to take sildenafil gives more detail about planning the dose around meals and anticipated sexual activity.
Food does not normally change the prescribed milligram strength, but it can change how quickly the medicine is absorbed. UK product information states that food may delay the onset compared with taking sildenafil while fasted. NHS advice notes that it is generally more predictable on an empty stomach.
A heavy or high-fat meal can delay the start of action. This may make a correct sildenafil dosage appear ineffective if the tablet is judged too early. Do not take another dose to compensate. Allow enough time and follow the maximum frequency on the label.
Alcohol can also make it harder to achieve or maintain an erection and may increase dizziness or other unwanted effects. Correct dosing cannot reliably overcome the effect of heavy drinking.
Not necessarily. Sildenafil 25mg, 50mg and 100mg use the same active ingredient, and the general timing advice is similar. The higher strength changes the amount of medicine taken, not the basic requirement for absorption and sexual stimulation.
Some people may experience a stronger response with 100mg, but that does not mean it will start immediately or remain effective for longer. The separate guide to how long sildenafil lasts explains the useful treatment window and why duration varies between individuals.
Choosing a higher dose only to try to make the medicine work faster can increase side effects without solving a timing, meal, alcohol, anxiety or stimulation problem.
A sildenafil dosage review may be appropriate when the prescribed strength is repeatedly ineffective, side effects are troublesome, health conditions change, or a new medicine is started. The review should consider how the tablet was used before concluding that the dose itself is wrong.
A clinician may ask about:
Severe renal impairment, hepatic impairment, alpha-blockers and some CYP3A4 inhibitors can affect the dose selected. Ritonavir has a particularly important interaction with sildenafil, so people taking it must not choose or change a dose without specialist advice.
Do not use a previous prescription, another person’s tablets or an online dosing calculator as a substitute for a current assessment.
One unsuccessful attempt does not always show that the sildenafil dosage is too low. Sildenafil may appear less effective when it is taken too close to sex, after a heavy meal, with excessive alcohol, without enough stimulation or during significant anxiety.
Review the instructions and the conditions in which it was used. The guide to common mistakes when taking sildenafil covers practical reasons for an inconsistent response. Do not respond by taking an additional tablet, mixing strengths or moving to 100mg without approval.
Persistent erectile dysfunction can also be associated with cardiovascular risk factors, diabetes, medicine effects, psychological factors or other health conditions. A prescriber or GP can assess whether a dose review, a different medicine or further investigation is appropriate.
Do not change sildenafil dosage when you have started a new medicine, experienced chest pain or fainting, developed a significant side effect, or have had a change in heart, blood-pressure, kidney, liver or eye health. Seek professional advice before the next dose.
Sildenafil must not be taken with nitrate medicines or nitric oxide donors used for chest pain, and it is contraindicated with riociguat. It may also be unsuitable for people with certain serious cardiovascular conditions, very low blood pressure, recent stroke or heart attack, severe liver impairment or particular eye conditions.
Do not combine sildenafil with tadalafil, vardenafil, avanafil or another sildenafil-containing treatment unless a clinician has specifically directed this. Combining medicines can increase the risk of low blood pressure and adverse effects.
Review the full Sildenafil safety information for contraindications, interactions and urgent warning signs.
The maximum recommended sildenafil dosage for erectile dysfunction is 100mg, and the maximum recommended dosing frequency is once per day. These limits do not mean that 100mg is suitable for everyone.
Seek urgent medical help for chest pain, a severe allergic reaction, sudden loss or marked change of vision or hearing, severe faintness, or a painful erection lasting longer than four hours. Tell the healthcare professional when sildenafil was taken. Do not use nitrate medicine for chest pain after taking sildenafil.
For less urgent but troublesome side effects, contact the prescriber or pharmacist. A lower dose, different timing or another treatment may be considered, but the next step should be based on clinical review rather than self-adjustment.
Buy sildenafil tablets online in the UK from Medicina Pharmacy, a GPhC-registered pharmacy. Sildenafil is a licensed prescription medicine used to treat erectile dysfunction and is available in 25mg, 50mg and 100mg strengths. Complete a confidential online consultation, and a UK-registered prescriber will review your medical information to determine whether treatment and your selected strength are appropriate.
Not sure which strength is right for you? Your prescriber will confirm the most suitable dosage during the consultation.
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The usual sildenafil dosage for many adults with erectile dysfunction is 50mg taken when needed, approximately one hour before sexual activity. It may be decreased to 25mg or increased to a maximum of 100mg according to effectiveness, tolerability, health conditions and interacting medicines.
Use only the prescribed strength, do not take more than one dose in a day, and do not increase or combine tablets because the response is delayed or incomplete. Food, alcohol, timing, stimulation and underlying health can all affect results.
Eligible adults can review current Sildenafil treatment options and complete the required assessment. The prescriber, rather than the price or strength label, determines whether sildenafil is suitable and which dose may be supplied.
Written by Saleh Ahmed (Independent Prescriber & Advanced Practitioner, GPhC 2065382).
Medically reviewed by Yasmeen Akthar (Superintendent Pharmacist, GPhC 2058731) and Mohammed Shajan Ali (Independent Prescriber, GPhC 2067785).
Last reviewed: ADD ACTUAL CLINICAL SIGN-OFF DATE BEFORE PUBLICATION.
The usual recommended dose for many adults is 50mg taken when needed, approximately one hour before sexual activity. A prescriber may decrease it to 25mg or increase it to 100mg according to response, tolerability and clinical suitability.
The maximum recommended dose for erectile dysfunction is 100mg. Sildenafil should not normally be taken more than once in a day, and 100mg is not suitable for everyone.
Sildenafil 25mg can be effective for some people and may be selected when a lower dose is clinically appropriate. Whether it is sufficient depends on response and suitability, which should be reviewed professionally.
Sildenafil 50mg is the usual recommended dose for many adults with erectile dysfunction. It may be adjusted down or up based on effect, side effects, health conditions and interacting medicines.
Sildenafil 100mg is the maximum recommended dose and is not normally an automatic first choice. It may be considered when a lower dose has been inadequate and the higher strength is clinically suitable.
Do not take an extra tablet or combine strengths unless a prescriber has explicitly instructed you to do so. Sildenafil should not normally be taken more than once in a day.
A higher dose does not reliably make sildenafil work faster. Timing, food, alcohol, absorption and sexual stimulation can affect onset. The general timing advice is similar across the 25mg, 50mg and 100mg strengths.
Sildenafil can be taken with or without food, but a heavy or high-fat meal can delay how quickly it works. Do not take another dose because the onset is slower after a meal.
Request a review when the medicine is repeatedly ineffective despite correct use, side effects are troublesome, your health changes, or you start another medicine. Do not change the dose yourself.
Sildenafil must not be taken with nitrates or riociguat and may be unsuitable with certain serious heart, blood-pressure, liver or eye conditions. A clinical assessment is required before supply.
Disclaimer: This page provides general information and is not a substitute for personal medical advice. Sildenafil is not suitable for everyone and can interact with other medicines. Use only the dose on the dispensing label and follow the instructions supplied by the prescriber or pharmacist. Seek urgent medical help for chest pain, a severe allergic reaction, sudden vision or hearing changes, or an erection lasting longer than four hours.
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