Sildenafil 100mg Tablets (Generic Viagra) for Erectile Dysfunction – UK

Description

At-a-Glance

• Strength: sildenafil citrate 100mg (PDE5 inhibitor).
• For erectile dysfunction (ED): helps you get and keep an erection when sexually aroused.
• Typical onset: 30–60 minutes; effects may last up to around 4 hours (varies).
• Maximum frequency: do not take more than 1 dose in 24 hours.
• Prescription-strength: supplied after a clinician suitability check.

What is Sildenafil 100mg?

Sildenafil 100mg is a prescription-strength treatment for erectile dysfunction (ED). It increases blood flow to the penis during sexual stimulation, helping you achieve a firmer erection. Sexual arousal is required for it to work.

How Sildenafil Works

Sildenafil is a PDE5 inhibitor. During sexual stimulation it relaxes blood vessels in penile tissue, which increases blood flow and supports an erection.

Who is Sildenafil 100mg for?

• Adult men (18+) with erectile dysfunction, when prescribed and used as directed.
• Men who have not had adequate response to lower strengths (your clinician decides).

Who should avoid Sildenafil 100mg?

• If you take nitrates for chest pain (angina) or take riociguat.
• If you have a serious heart or liver problem, or have been advised to avoid sexual activity.
• If you have low blood pressure, or a rare inherited eye disease (e.g., retinitis pigmentosa).
• If you’ve ever had an allergic reaction to sildenafil.

Directions & Dosage (How to Take Sildenafil 100mg)

Missed dose

Not applicable for ‘as-needed’ use. Do not take extra tablets to make up for a missed opportunity.

How quickly does Sildenafil 100mg work – and how long does it last?

• Onset: often 30–60 minutes (varies).
• Duration: effects may last up to around 4 hours (varies).
• Best results: take on a relatively empty stomach; a heavy/high-fat meal may delay onset.

Ingredients

• Active ingredient: sildenafil citrate 100mg (equivalent to 100mg sildenafil).
• Other ingredients (excipients) vary by manufacturer — see the patient information leaflet (PIL).

Side Effects

Common

• Headache
• Flushing
• Dizziness
• Indigestion
• Blocked nose
• Visual changes (e.g., blue tinge)

Seek urgent medical help

• Chest pain
• Sudden vision loss or hearing changes
• Erection lasting longer than 4 hours (priapism)

Interactions & Warnings

• Do not use with nitrates (angina medicines) or with riociguat.
• Tell your clinician/pharmacist if you take alpha-blockers (for prostate/BP) – risk of low blood pressure.
• Some antibiotics, antifungals, and HIV medicines can increase sildenafil levels – declare all medicines in your consultation.
• Avoid mixing with other ED medicines unless a clinician provides a plan.

Buying Sildenafil 100mg Online in the UK 

• Step 1: Complete the online medical questionnaire (health history + current medicines).
• Step 2: Clinician review to confirm suitability and dose.
• Step 3: Prescription issued (if appropriate) and medication dispensed by a regulated pharmacy.
• Step 4: Discreet, trackable UK delivery.

Available Strengths & Alternatives

• Sildenafil 50mg (link: /sildenafil-50mg-tablets/)
• Sildenafil 25mg (link: /sildenafil-25mg-tablets/)
• Explore more options in our Erectile Dysfunction treatments category (link: /prescription-treatments/erectile-dysfunction/)

FAQs

How quickly does Sildenafil 100mg work?

Effects often begin within 30-60 minutes, and you can take it up to 4 hours before sex.

Can I take Sildenafil with alcohol?

Limit alcohol – excess can reduce effectiveness and increase dizziness and side effects.

Is it safe for daily use?

Sildenafil is usually taken as needed. Do not take more than 1 dose in 24 hours. Speak to a clinician if you need frequent dosing.

How long does it last?

Effects may last up to around 4 hours, depending on food, dose, and individual factors.

What if 100mg doesn’t work?

Do not exceed the dose. Check timing, food, stimulation, and interactions. If it still isn’t effective, consult your prescriber for alternatives.

Patient Information Leaflet

This page is a summary and does not replace the Patient Information Leaflet (PIL). Always follow the directions supplied with your medicine and seek medical advice if unsure.