Many men wonder whether sildenafil increases stamina during sexual activity. Sildenafil, widely known as Viagra, is a phosphodiesterase type 5 (PDE5) inhibitor licensed in the UK for treating erectile dysfunction. Whilst it effectively facilitates achieving and maintaining an erection, it does not directly enhance physical endurance or delay ejaculation. Understanding what sildenafil does—and does not do—is essential for safe, appropriate use. This article examines the evidence surrounding sildenafil's effects on sexual performance, addresses common misconceptions, and outlines NHS guidance for safe prescribing and use of this widely prescribed medication.

What Is Sildenafil and How Does It Work?

Sildenafil is a prescription medication primarily used to treat erectile dysfunction (ED) in men. It belongs to a class of drugs called phosphodiesterase type 5 (PDE5) inhibitors. Originally developed by Pfizer, sildenafil is widely known by its brand name Viagra, though generic versions are now available throughout the UK. In the UK, sildenafil is available as a prescription medicine, while Viagra Connect (50mg) can be supplied by pharmacists following an assessment, without requiring a GP prescription.

The mechanism of action of sildenafil is highly specific to the physiological process of achieving an erection. During sexual stimulation, the body releases nitric oxide in the erectile tissue of the penis. This triggers the production of cyclic guanosine monophosphate (cGMP), a chemical messenger that relaxes smooth muscle cells in the blood vessels of the penis, allowing increased blood flow. Sildenafil works by inhibiting the PDE5 enzyme, which normally breaks down cGMP. By blocking this enzyme, sildenafil helps maintain higher levels of cGMP, thereby enhancing and prolonging the blood flow necessary for an erection.

It is crucial to understand that sildenafil does not work without sexual stimulation—it does not create spontaneous erections or increase sexual desire. The medication typically begins to work within 30 to 60 minutes of oral administration, with effects lasting approximately four to six hours. High-fat meals can delay the onset of action. The standard starting dose in the UK is 50mg, which may be adjusted by a healthcare professional based on efficacy and tolerability. Sildenafil should not be taken more than once per day.

Sildenafil is also licensed under the brand name Revatio for treating pulmonary arterial hypertension, though at different dosages. For erectile dysfunction, it is indicated for adult men only and is not licensed for use by women or those under 18 years of age.

Sildenafil's Effects on Sexual Performance and Duration

A common question surrounding sildenafil concerns whether it increases sexual stamina or prolongs the duration of sexual activity. It is important to clarify what sildenafil does and does not do in terms of sexual performance. Sildenafil is designed specifically to facilitate the achievement and maintenance of an erection sufficient for sexual intercourse—it does not directly affect ejaculation timing, sexual endurance, or overall stamina.

Clinical studies demonstrate that sildenafil significantly improves erectile function in men with ED. Men taking sildenafil often report improved confidence and reduced performance anxiety, which may indirectly contribute to a more satisfying sexual experience. However, there is no established link between sildenafil use and increased physical stamina or delayed ejaculation.

Some men may perceive that sildenafil increases their stamina because the improved erectile function allows them to engage in sexual activity for longer periods without losing their erection. This is fundamentally different from increasing physical endurance or delaying climax. The medication addresses the mechanical aspect of erectile function rather than affecting the neurological or psychological components of sexual stamina.

For men experiencing premature ejaculation alongside erectile dysfunction, sildenafil alone may not provide adequate treatment. UK clinical guidance suggests that premature ejaculation requires different therapeutic approaches, potentially including dapoxetine (a licensed SSRI specifically for premature ejaculation), topical anaesthetics such as lidocaine/prilocaine spray, or in some cases, off-label use of daily SSRIs. Men concerned about both conditions should discuss comprehensive treatment options with their GP, as combination approaches may sometimes be appropriate under medical supervision.

Some individuals report anecdotally that they can achieve a second erection more quickly after orgasm when using sildenafil, though this varies considerably between individuals and is not a primary indication for the medication.

Common Misconceptions About Sildenafil and Stamina

Several widespread misconceptions exist regarding sildenafil's effects on sexual stamina and performance, which can lead to unrealistic expectations or inappropriate use of the medication. Understanding these misconceptions is essential for safe and effective treatment.

Misconception 1: Sildenafil acts as an aphrodisiac or increases libido

Sildenafil does not increase sexual desire or arousal. It works purely on the physical mechanism of erection and requires sexual stimulation to be effective. Men with low libido due to hormonal imbalances, psychological factors, or other medical conditions will not experience increased desire from taking sildenafil alone.

Misconception 2: Sildenafil delays ejaculation or treats premature ejaculation

There is no robust clinical evidence that sildenafil directly delays ejaculation or increases ejaculatory control. Whilst some men may feel more relaxed and less anxious about their performance when erectile function improves, this is an indirect psychological benefit rather than a pharmacological effect on ejaculation timing.

Misconception 3: Higher doses provide better stamina or performance

Taking more than the prescribed dose does not enhance stamina and significantly increases the risk of adverse effects. The maximum recommended dose is 100mg in a 24-hour period, and sildenafil should not be taken more than once daily. Any dose adjustments should be made by or with advice from a healthcare professional. Exceeding the recommended dose provides no additional benefit and may cause serious side effects including severe hypotension, priapism, or cardiovascular complications.

Misconception 4: Sildenafil is suitable for recreational use by men without ED

Using sildenafil without a medical need carries unnecessary risks and provides no proven benefit to sexual stamina in men with normal erectile function. Recreational use may mask underlying health conditions and exposes users to potential adverse effects without medical supervision.

Misconception 5: Sildenafil works immediately and continuously

Sildenafil requires time to be absorbed and metabolised, typically taking 30-60 minutes to become effective. High-fat meals can delay this onset further. Its effects are temporary, lasting approximately four to six hours, and it does not provide continuous erectile function throughout this period—sexual stimulation is still required for each erection.

Safe Use of Sildenafil: NHS Guidelines and Precautions

Safe use of sildenafil requires adherence to NHS and MHRA guidelines, proper medical assessment, and awareness of potential contraindications and adverse effects. Sildenafil should only be used following a thorough consultation with a qualified healthcare professional or, for Viagra Connect 50mg, after assessment by a pharmacist.

Prescribing and Assessment

Before prescribing sildenafil, healthcare professionals should conduct a comprehensive assessment including:

• Medical history, particularly cardiovascular conditions

• Current medications to identify potential drug interactions

• Blood pressure measurement

• Assessment of underlying causes of erectile dysfunction

• Discussion of lifestyle factors (smoking, alcohol, exercise)

• Consider basic investigations: blood glucose/HbA1c, lipid profile, and morning testosterone if hypogonadism is suspected

NICE guidance recommends that men with ED should be evaluated for cardiovascular risk factors, as erectile dysfunction can be an early indicator of cardiovascular disease. Referral to cardiology may be appropriate for men with high cardiovascular risk, and to urology for refractory cases, penile deformity, or complex presentations.

Contraindications and Cautions

Sildenafil is contraindicated in men:

• Taking nitrate medications (such as glyceryl trinitrate for angina)

• Taking nicorandil

• Taking riociguat (a soluble guanylate cyclase stimulator)

• For whom sexual activity is inadvisable due to cardiovascular status

Sildenafil should be used with caution in men with:

• Recent stroke or myocardial infarction (within 6 months)

• Unstable angina or severe heart failure

• Severe hepatic impairment (consider starting at 25mg)

• Hereditary retinal disorders

• Alpha-blockers (ensure haemodynamic stability, start at 25mg, consider temporal separation of doses)

Important Drug Interactions

• Potent CYP3A4 inhibitors (e.g., ketoconazole, ritonavir, cobicistat, clarithromycin): maximum dose 25mg; with ritonavir, do not exceed 25mg within 48 hours

• Grapefruit juice: may increase sildenafil levels; avoid

• Amyl nitrite ('poppers'): dangerous hypotension; strictly avoid

Common Adverse Effects

The most frequently reported side effects include:

• Headache (affecting approximately 10-15% of users)

• Facial flushing

• Indigestion or dyspepsia

• Nasal congestion

• Visual disturbances (blue tinge to vision, increased light sensitivity)

These effects are generally mild to moderate and transient.

When to Seek Urgent Medical Attention

Patients should contact emergency services or attend A&E immediately if they experience:

• An erection lasting more than four hours (priapism)

• Sudden vision loss

• Sudden hearing loss

• Chest pain during sexual activity

• Severe allergic reactions

Patients should report suspected adverse reactions to the MHRA through the Yellow Card Scheme.

Practical Safety Advice

Patients should take sildenafil approximately one hour before planned sexual activity (allowing longer if taken with food), avoid excessive alcohol consumption (which can impair erectile function), and never exceed the prescribed dose. Sildenafil should not be taken more than once daily. It should be stored safely away from children and never shared with others. Men should only obtain sildenafil through legitimate sources—purchasing from unregulated online suppliers carries significant risks including counterfeit medications containing dangerous substances.

Regular review with a healthcare professional is advisable to assess ongoing efficacy, tolerability, and any changes in overall health status that might affect treatment suitability.

Frequently Asked Questions