Key Takeaways: How to Use Sildenafil Safely

Optimal Timing: Take 30-60 minutes before sexual activity
Starting Dose: 50mg is standard, adjust based on response and tolerability
Frequency: Maximum once every 24 hours
Food Effect: Take on empty stomach for fastest onset (1 hour delay with high-fat meal)
Essential Requirement: Sexual stimulation needed for medication to work
Absolute Contraindication: Never take with nitrate medications (dangerous blood pressure drop)

Sildenafil requires proper timing and administration to work effectively for erectile dysfunction. Following the correct usage guidelines ensures you get the maximum benefit while minimising potential side effects and risks.

Emergency Medical Warning

If you experience chest pain, an erection lasting more than 4 hours (priapism), sudden vision loss, or severe allergic reaction while taking sildenafil, seek immediate medical attention. Do not take sildenafil with nitrate medications.

How to Take Sildenafil: Step by Step Usage Guide

Following these steps ensures you use sildenafil correctly and safely for optimal results in treating erectile dysfunction.

Consultation & Prescription

Speak with a UK-registered doctor who will assess your suitability for sildenafil. Never use sildenafil without a proper prescription, as it requires medical evaluation of your heart health and medication interactions.

Dose Selection

Start with the prescribed dose (usually 50mg). Your doctor may recommend starting with 25mg if you're over 65, have liver or kidney problems, or are taking certain other medications.

Timing & Planning

Take sildenafil approximately 30-60 minutes before planned sexual activity. The medication typically remains effective for 4-6 hours after taking, but works best within the first few hours.

Administration

Swallow the tablet whole with a glass of water. Do not crush, chew, or break the tablet. Sildenafil can be taken with or without food, but avoid heavy, high-fat meals before taking.

Sexual Stimulation

Remember that sildenafil requires sexual stimulation to work. The medication enhances your body's natural response but doesn't cause an erection spontaneously.

Dose Adjustment

If 50mg is too strong or causes side effects, reduce to 25mg. If ineffective, your doctor may increase to 100mg. Never take more than 100mg in 24 hours.

🗒️ Important Reminder: Sildenafil should only be taken once per day. Taking more frequent doses won't increase effectiveness and significantly increases the risk of side effects. If a dose doesn't work as expected, wait until the next day to try again.

Sildenafil Dosage Guide

Sildenafil comes in three strengths: 25mg, 50mg, and 100mg tablets. The correct dose depends on your individual response, tolerance, and medical circumstances.

Standard Dosage Recommendations

Dose Strength	Recommended For	Timing & Frequency	Maximum Effect
25mg	Elderly (≥65), liver/kidney impairment, those on CYP3A4 inhibitors	30-60 mins before activity, once daily max	Mild to moderate ED, good for first-time users testing tolerance
50mg	Most adults with ED (standard starting dose)	30-60 mins before activity, once daily max	Effective for majority of ED cases, balanced efficacy/safety
100mg	When 50mg ineffective, severe ED cases (doctor's advice only)	30-60 mins before activity, once daily max	Maximum therapeutic effect, higher side effect risk

Dosage Adjustment Scenarios

If Dose is Too Strong

Experiencing headaches, flushing, indigestion
Vision changes (blue tint, light sensitivity)
Dizziness or nasal congestion
Action: Reduce to next lower dose

If Dose is Too Weak

Insufficient erection for sexual activity
Erection doesn't last long enough
No noticeable effect after 1 hour
Action: Consult doctor about increasing dose

If No Effect at All

No improvement after 2-3 attempts
Remember: Requires sexual stimulation
May need different ED treatment
Action: Consult doctor for reassessment

🗒️ Dosage Warning: Never exceed 100mg in 24 hours. Higher doses don't increase efficacy and significantly raise the risk of serious side effects including priapism (painful prolonged erection), severe hypotension, and vision changes.

Who Should Use Sildenafil

Sildenafil is specifically designed for certain individuals with erectile dysfunction and should only be used under medical supervision.

Appropriate Candidates for Sildenafil

Primary Indication

Adult men with erectile dysfunction - difficulty achieving or maintaining an erection sufficient for satisfactory sexual activity.

Age Group

Men aged 18 years and older - Not approved for use in children or adolescents.

ED Causes

Suitable for ED from various causes: psychological, vasculogenic, diabetes-related, or mixed etiology.

Medical Evaluation Requirements

Assessment Needed	Reason	Typical Evaluation
Cardiovascular Health	Sildenafil affects blood pressure; heart must withstand sexual activity	Blood pressure check, heart history, stress test if indicated
Current Medications	Dangerous interactions with nitrates and some other drugs	Complete medication review including over-the-counter medicines
ED Underlying Cause	To ensure appropriate treatment and rule out reversible causes	Medical history, possible blood tests (testosterone, glucose)
Vision Assessment	Rare risk of vision changes, especially with pre-existing eye conditions	Discussion of eye health history, particularly NAION risk factors

🗒️ Clinical Insight: Good candidates for sildenafil typically have at least some intact nitric oxide production (needed for the medication to work). Those with severe nerve damage or very poor blood flow may respond less effectively.

Who Should Not Use Sildenafil

Certain individuals must absolutely avoid sildenafil due to potentially life-threatening risks and complications.

Absolute Contraindications

Nitrate Users

Absolute prohibition with any nitrate medication (for angina) or recreational poppers (amyl nitrite). Combination causes dangerous blood pressure drop.

Rictoiguat Users

Contraindicated with rictoiguat (for pulmonary hypertension). Combined use can cause severe hypotension.

Recent Cardiovascular Events

Avoid if recent heart attack, stroke, or life-threatening arrhythmia. Sexual activity may strain compromised cardiovascular system.

Additional Precautions and Warnings

Condition	Risk Level	Precaution Needed
Severe Liver Impairment	High	Maximum 25mg dose, close monitoring required
Severe Kidney Impairment	High	Maximum 25mg dose, creatinine clearance <30 mL/min
Hypotension (low blood pressure)	High	Sildenafil may further lower blood pressure
Hypertension (high blood pressure)	Medium	Ensure blood pressure controlled before use
Anatomical Penile Deformity	Medium	Risk of priapism; includes Peyronie's disease
Bleeding Disorders	Medium	Increased bleeding risk (e.g., haemophilia)
Stomach Ulcers	Medium	May exacerbate gastrointestinal bleeding
Retinitis Pigmentosa	Medium	Genetic eye disorder - use with extreme caution

🗒️ Safety Alert: Sildenafil is not for use by women, children, or men without erectile dysfunction. Using it recreationally or for enhancement without medical need is dangerous and medically inappropriate.

To Be Taken With or Without Food

Food significantly affects how quickly sildenafil starts working, but doesn't prevent it from working eventually.

How Food Affects Sildenafil Absorption

Empty Stomach (Recommended)

Onset Time: 30-60 minutes

Peak Concentration: Maximum absorption

Effectiveness: Optimal

Best For: Fastest results, predictable timing

With Light Meal

Onset Time: 45-75 minutes

Peak Concentration: Slightly reduced

Effectiveness: Good

Best For: Those prone to stomach upset

With High-Fat Meal

Onset Time: Delayed by 1+ hours

Peak Concentration: Reduced by 30%

Effectiveness: Reduced and unpredictable

Recommendation: Avoid for optimal results

Food Interaction Guidelines

Food Type	Effect on Sildenafil	Recommendation
High-fat meals (burgers, chips, fried foods)	Delays absorption by 60+ minutes, reduces peak concentration by 30%	Avoid within 2 hours of taking sildenafil
Light meals (sandwich, salad, fruit)	Minimal delay (15-30 minutes), slight absorption reduction	Acceptable if needed to prevent stomach upset
Grapefruit juice	Inhibits metabolism, increases sildenafil levels and side effect risk	Avoid completely on days taking sildenafil
Alcohol	Can impair erection ability, increases dizziness and blood pressure drop risk	Limit alcohol, avoid excessive consumption

🗒️ Practical Tip: If you've eaten a heavy meal and need to take sildenafil, wait at least 2 hours after eating, or plan sexual activity for 2-3 hours after taking the medication to allow for delayed absorption.

Special Conditions: Pregnancy, Breastfeeding & Other Considerations

While sildenafil is not indicated for women, understanding its use in special populations and conditions is important for comprehensive patient care.

Pregnancy and Breastfeeding

Pregnancy Category

Not indicated for use in women - Sildenafil is not approved for use during pregnancy. Some specialised hospital settings may use it for specific pregnancy-related conditions under close supervision, but this is not relevant for ED treatment.

Breastfeeding

Not indicated for use in women - Since sildenafil is not prescribed to women for erectile dysfunction, breastfeeding considerations don't apply. However, if accidentally ingested by a breastfeeding woman, consult a doctor immediately.

Other Special Considerations

Special Condition	Consideration	Recommendation
Elderly (≥65 years)	Reduced clearance, increased sensitivity	Start with 25mg dose, monitor closely for side effects
Hepatic Impairment	Reduced metabolism, increased exposure	Severe impairment: max 25mg; mild-moderate: consider 25mg starting dose
Renal Impairment	Reduced elimination, increased exposure	Creatinine clearance <30 mL/min: max 25mg; 30-50 mL/min: consider 25mg start
Diabetes	May have reduced response due to neuropathy/vascular changes	May require higher dose (100mg), monitor blood glucose effects
Prostate Problems	Alpha-blockers interaction risk	Separate doses by 4+ hours if taking alpha-blockers for prostate
Driving & Machinery	May cause dizziness, visual disturbances	Don't drive/operate machinery until you know how it affects you

Lactose and Sodium Content

Lactose Content

Sildenafil tablets contain lactose monohydrate. If you have lactose intolerance or galactose intolerance, consult your doctor before use.

Sodium Content

Each tablet contains less than 1 mmol sodium (23 mg), which is essentially 'sodium-free' and suitable for low-sodium diets.

🗒️ Storage Information: Store sildenafil at room temperature (15-30°C), in original packaging, away from moisture and direct sunlight. Keep out of sight and reach of children. Do not use after expiry date printed on packaging.

Sildenafil Usage FAQs

How long before sex should I take sildenafil?

Take sildenafil 30-60 minutes before planned sexual activity. If taken on an empty stomach, it may work in 30 minutes; with a heavy meal, it could take 2 hours. The effects typically last 4-6 hours.

Can I take sildenafil every day?

No, sildenafil should not be taken daily for erectile dysfunction. Maximum frequency is once per 24 hours. Daily use is only for specific pulmonary hypertension treatment with different dosing.

What should I do if sildenafil doesn't work?

If ineffective after 2-3 attempts: 1) Ensure sexual stimulation, 2) Take on empty stomach, 3) Try different timing, 4) Consult your doctor about dose adjustment or alternative treatments.

Can I cut sildenafil tablets in half?

Tablets should be swallowed whole with water. However, if prescribed a lower dose, your doctor can prescribe the appropriate strength. Don't split tablets unless advised by your doctor.

Is it safe to drink alcohol with sildenafil?

Limit alcohol as it can impair erection ability and increase side effects like dizziness and blood pressure drops. Heavy drinking with sildenafil is not recommended.

Ready to Start Sildenafil Treatment?

If you're experiencing erectile dysfunction and believe sildenafil could help, speak with a UK-registered doctor through our confidential online consultation service. Get genuine medication with proper medical supervision.