Sildenafil Tablets
Sildenafil is a prescription treatment for erectile dysfunction in adult men. Available in three strengths (25mg, 50mg, 100mg), it is taken as needed about 1 hour before sexual activity. This medication is available through Chemist Doctor's regulated online service following a consultation with UK-licensed clinicians.
You must complete a short online consultation so that our prescriber can ensure that the treatment is suitable for you.
| Product Name: | Sildenafil |
|---|---|
| Manufacturer: | Various |
| Active Ingredient: | Sildenafil citrate |
| Administration: | Oral |
| Presentation: | Film-coated tablets |
| Available Strengths: | 25mg, 50mg & 100mg |
| Prescription Required: | Yes |
| Dosage: | Take 1 tablet ~1 hour before sexual activity (max once daily) |
| Onset/Duration: | Onset 30–60 minutes; lasts 4–5 hours |
| Use with alcohol: | Avoid excessive consumption |
| Package | 25mg | 50mg | 100mg |
|---|---|---|---|
| 4 Tablets | £9.99 | £9.99 | £9.99 |
| 8 Tablets | £16.99 | £16.99 | £16.99 |
| 12 Tablets | £21.99 | £21.99 | £21.99 |
| 16 Tablets | £25.95 | £25.95 | £25.95 |
| 20 Tablets | £26.95 | £26.95 | £26.95 |
| 24 Tablets | £27.95 | £27.95 | £27.95 |
| 28 Tablets | £28.95 | £28.95 | £28.95 |
| 32 Tablets | £29.95 | £29.95 | £29.95 |
| Sildenafil is a PDE5 inhibitor for erectile dysfunction in men ≥18 years. Take one tablet (25mg, 50mg, or 100mg) about one hour before sexual activity. Effects last 4–5 hours. Do not take more than once daily. Avoid nitrates and excessive alcohol. Contraindicated in patients taking nitrates, with severe heart or liver problems, recent stroke or heart attack, low blood pressure, certain eye diseases, or history of vision loss due to NAION. May cause dizziness, vision changes, or priapism (seek immediate help for erections >4 hours). | |||
| This treatment requires an online consultation for review by our medical team. The decision to supply the specific treatment and quantity requested will be based on whether our medical team are satisfied that it will be safe, appropriate, and effective. | |||
Table of Contents
- What is Sildenafil?
- What is Sildenafil Used For?
- Before Using Sildenafil
- Sildenafil Contraindications
- Special Population Considerations
- Sildenafil and Other Medicines
- Pregnancy & Breastfeeding
- Driving & Machine Operation
- Sildenafil Ingredients
- How to Use Sildenafil
- Sildenafil Dosage Guidelines
- Missed Dose Management
- Overdose Information
- Sildenafil Side Effects
- How to Store Sildenafil
- Sildenafil Pack Information
- Sildenafil FAQs
What is Sildenafil?
Sildenafil is a prescription medication containing the active substance sildenafil citrate, presented as film-coated tablets. It belongs to a class of medicines called phosphodiesterase type 5 (PDE5) inhibitors.
Mechanism of Action
Sildenafil works through a targeted mechanism:
- Vasodilation: Enhances blood flow to penile tissues during sexual stimulation
- PDE5 inhibition: Blocks the enzyme that breaks down cyclic guanosine monophosphate (cGMP)
- Erection facilitation: Maintains higher cGMP levels, supporting natural erection processes
Think of Sildenafil as a key that unlocks the natural physiological response to sexual stimulation, allowing for improved blood flow to the penis when you're sexually aroused.
What is Sildenafil Used For?
Sildenafil is indicated for the treatment of erectile dysfunction in adult men.
Approved Patient Groups
| Patient Group | Age Requirements | Additional Criteria |
|---|---|---|
| Adult men (≥18 years) | 18 years and older | Diagnosis of erectile dysfunction No contraindications for PDE5 inhibitors |
Important Safety Notice:
Discontinue immediately and seek medical help if you experience:
- Chest pain, dizziness, or nausea during sexual activity
- Erection lasting more than 4 hours (priapism)
- Sudden vision loss or hearing changes
- Allergic reactions (rash, itching, swelling)
Before Using Sildenafil
Essential considerations before initiating treatment:
Medical History Assessment
- Cardiovascular disease history
- Liver or kidney impairment
- Blood cell disorders (sickle cell anemia, leukemia)
- Penile deformities (Peyronie's disease)
- History of vision or hearing problems
- Stomach ulcers or bleeding disorders
Required Baseline Tests
- Cardiovascular assessment
- Blood pressure measurement
- Liver and kidney function tests (if indicated)
Sildenafil Contraindications
Absolute contraindications where Sildenafil must not be used:
Absolute Contraindications
- Concomitant use of nitrates (for chest pain)
- Hypersensitivity to sildenafil or excipients
- Severe cardiovascular disease
- Recent stroke or heart attack (within last 6 months)
Special Warnings
| Condition | Precaution |
|---|---|
| Cardiovascular disease | Sexual activity may pose cardiac risk |
| Liver impairment | Dose adjustment may be necessary |
| Kidney impairment | Dose adjustment may be necessary |
| Penile deformity | Increased risk of priapism |
Special Population Considerations
Elderly Patients (≥65 years)
- Increased sensitivity to effects
- May require lower starting dose
- Higher likelihood of concomitant medications
Renal Impairment
- Mild-moderate impairment: 25mg starting dose recommended
- Severe impairment: Use with caution
Hepatic Impairment
- Mild-moderate impairment: 25mg starting dose recommended
- Severe impairment: Maximum 25mg dose
Sildenafil and Other Medicines
Significant interactions requiring monitoring:
High-Risk Combinations
- Nitrates: Dangerous blood pressure drop - absolute contraindication
- Alpha-blockers: Increased hypotension risk - separate dosing times
- HIV protease inhibitors: Increased sildenafil levels - maximum 25mg in 48 hours
Other Interactions
- Antifungal medications (ketoconazole, itraconazole)
- Antibiotics (erythromycin, clarithromycin)
- Blood pressure medications
- Other erectile dysfunction treatments
Pregnancy & Breastfeeding
Pregnancy
- Not indicated for use in women
- No established safety profile during pregnancy
Breastfeeding
- Not indicated for use in women
- Unknown if sildenafil passes into breast milk
Driving & Machine Operation
- Possible dizziness or visual disturbances
- Caution advised when driving or operating machinery
- Do not drive if experiencing vision changes or dizziness
Sildenafil Ingredients
Active Substance
- Sildenafil citrate
Excipients
| Ingredient | Function |
|---|---|
| Microcrystalline cellulose | Filler |
| Calcium hydrogen phosphate | Filler |
| Croscarmellose sodium | Disintegrant |
| Magnesium stearate | Lubricant |
| Hypromellose | Coating agent |
| Titanium dioxide (E171) | Colorant |
| Lactose | Filler |
| Triacetin | Plasticizer |
Lactose Content
- Contains lactose
- Not suitable for lactose intolerant patients
How to Use Sildenafil
Administration Instructions
- Take tablet with a glass of water
- Approximately 30-60 minutes before sexual activity
- Can be taken with or without food
- Avoid high-fat meals which may delay absorption
Important Notes
- Sexual stimulation is required for effectiveness
- Do not take more than once daily
- Not an aphrodisiac - will not increase libido
Sildenafil Dosage Guidelines
Standard Dosing Schedule
| Patient Group | Starting Dose | Maximum Dose | Frequency |
|---|---|---|---|
| Most patients | 50mg | 100mg | Once daily |
| Elderly (≥65) | 25mg | 100mg | Once daily |
| Hepatic impairment | 25mg | 100mg | Once daily |
| Renal impairment | 25mg | 100mg | Once daily |
Dose Adjustment Criteria
- Increase to 100mg if 50mg is ineffective
- Decrease to 25mg if 50mg causes side effects
- Maximum recommended frequency: once per day
Missed Dose Management
General Principles
- Sildenafil is taken as needed, not regularly
- No fixed dosing schedule
- Take when needed for sexual activity
Timing Considerations
Take approximately 30-60 minutes before anticipated sexual activity. Effects may last up to 4-5 hours.
Overdose Information
Symptoms
- Severe headache
- Dizziness
- Fainting
- Prolonged erection
- Vision changes
Management
- Seek immediate medical attention
- Bring medication packaging
- Supportive treatment:
- Monitor blood pressure
- Treat symptoms as they occur
Possible Side Effects
Very Common (more than 1 in 10 people)
- Headache
- Facial flushing
Common (1 in 10 to 1 in 100 people)
- Dizziness
- Visual disturbances (blue tinge, light sensitivity)
- Nasal congestion
- Indigestion
- Nausea
Uncommon (1 in 100 to 1 in 1000 people)
- Fainting
- Eye pain
- Erection lasting more than 4 hours
- Allergic reactions
Rare (1 in 1000 to 1 in 10,000 people)
- Sudden vision loss
- Sudden hearing loss
- Heart attack
- Stroke
Serious Side Effects
| Effect | Frequency | Action Required |
|---|---|---|
| Priapism (prolonged erection) | Uncommon | Seek immediate medical help |
| Sudden vision loss | Rare | Discontinue and seek emergency care |
| Sudden hearing loss | Rare | Discontinue and seek medical advice |
| Severe allergic reaction | Rare | Seek emergency treatment |
How to Store Sildenafil
Storage Conditions
- Store below 25°C
- Keep in original packaging
- Protect from light and moisture
Disposal
- Return unused medication to pharmacy
- Do not dispose in household waste
- Keep out of reach of children
Sildenafil Pack Information
Pack Sizes
- 4 tablets
- 8 tablets
- 12 tablets
- 16 tablets
Appearance
- Round, blue, film-coated tablets
- Engraved with "PG" on one side
- Dose strength specific markings
Where Can I Buy Sildenafil Online in the UK
Secure Sildenafil Prescription & Next-Day Delivery Service
Order Sildenafil with confidence through our UK-registered medical prescribers, who review all requests within 4 working hours. We guarantee same-day prescription approval for eligible patients and dispatch orders placed before 3pm for next-day tracked delivery.
Our Sildenafil service combines competitive pricing with strict adherence to MHRA safety standards, ensuring your medication is dispensed through GPhC-registered pharmacies. Every purchase includes discreet packaging and a GDPR-compliant consultation process.
Our clinical team ensures:
- Comprehensive medical history review
- Cardiovascular risk assessment
- Drug interaction checks
- Personalised dosing guidance
Always consult your GP before starting treatment for erectile dysfunction. Not recommended for men with heart conditions or those taking nitrate medications.
Sildenafil FAQs
How does Sildenafil work for erectile dysfunction?
Sildenafil works by inhibiting the phosphodiesterase type 5 (PDE5) enzyme, which increases blood flow to the penis during sexual stimulation, helping to achieve and maintain an erection.
How long does it take for Sildenafil to work?
Sildenafil typically begins working within 30-60 minutes after taking the tablet, with optimal effects occurring when taken on an empty stomach.
How long do the effects of Sildenafil last?
The effects of Sildenafil can last for up to 4-5 hours, though the duration may vary between individuals.
Can I drink alcohol while taking Sildenafil?
Excessive alcohol consumption can impair your ability to get an erection and may increase the risk of side effects like dizziness. Moderate alcohol consumption is generally acceptable.
Should I take Sildenafil with food?
Sildenafil can be taken with or without food, but taking it with a high-fat meal may delay its absorption and onset of action.
What are the most common side effects of Sildenafil?
The most common side effects include headache, flushing, indigestion, nasal congestion, dizziness, and visual disturbances. These are usually mild and temporary.
Why can't I take Sildenafil with nitrates?
Sildenafil can significantly increase the blood pressure-lowering effects of nitrates, potentially leading to dangerous drops in blood pressure. This combination is contraindicated.
Can I take Sildenafil if I have heart problems?
Men with certain heart conditions may not be suitable candidates for Sildenafil. A thorough medical assessment is necessary to determine if it's safe for you.
What is the right dosage of Sildenafil for me?
The appropriate dosage depends on various factors including your age, overall health, and response to the medication. Typically, treatment starts with 50mg, which may be adjusted to 25mg or 100mg based on efficacy and tolerance.
How often can I take Sildenafil?
Sildenafil should not be taken more than once per day. Allow at least 24 hours between doses.
Related Guides
Medical Content Manager
Nabeel is a co-founder, and medical content manager of Chemist Doctor. He works closely with our medical team to ensure the information is accurate and up-to-date.
Medical Doctor
Dr. Waqas is a GMC registered doctor and medical reviewer at Chemist Doctor. He ensures clinical accuracy and reliability across health content.
Medical Director
Usman is a co-founder, and medical director of Chemist Doctor. He leads the organisation's strategic vision, bridging clinical and operational priorities.
Review Date: 08 May 2025
Next Review: 10 December 2025
Published on: 08 May 2025
Last Updated: 09 May 2025
Getting Sildenafil is quick and easy with our simple 4‑step process:
Start Consultation
Complete our brief health questionnaire about your medical history and current health.
Medical Review
UK‑registered clinicians review your consultation for safe prescribing.
Pharmacy Processing
If approved, our partner pharmacy prepares your medication.
Fast Dispatch
Your Sildenafil order is dispatched via your chosen delivery method.
At Chemist Doctor, we respect your privacy and ensure complete discretion at every step.
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All orders are sent in tamper‑evident, plain packaging.
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Private Consultations
All consultations are conducted privately by UK‑registered clinicians.
Anonymous Billing
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Will my GP be informed about my Sildenafil order?
Only with your consent. We recommend updating your GP for continuity of care.
We offer reliable delivery options for Sildenafil:
| Service Type | Delivery Speed | Order Cut‑off | Carrier |
|---|---|---|---|
| Standard Delivery | 2–3 business days | No cut‑off | Royal Mail |
| Premium Next‑Day Delivery | Next business day | 3 PM weekdays | Royal Mail 24 |
Next‑day delivery applies to orders approved before 3 PM within England, Scotland, Wales, and Northern Ireland.
Restrictions: We cannot deliver to Republic of Ireland, Continental Europe, USA, or Canada.
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How long do refunds take?
Card: Typically 3–5 days. Bank transfer: We’ll contact you to return funds.
Why was my order declined?
Declined orders are not charged. Card authorisations usually release in 3–5 days.
Can I return prescription medication?
No. UK law prohibits returns of dispensed prescription medicines.
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