How Does Viagra Work? UK Pharmacist Guide | Cured

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How Does Viagra Work? Understanding ED Treatment

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How Does Viagra Work? Understanding ED Treatment

Understanding how does viagra work for erectile dysfunction is essential before starting treatment. Viagra contains sildenafil citrate, a PDE5 inhibitor that enhances blood flow to the penis during sexual arousal, helping men achieve and maintain erections. At Cured Pharmacy, we offer genuine UK-licensed sildenafil from £0.45 per tablet, with free clinical assessment by UK prescribers.

The Science Behind How Viagra Works

Viagra works by inhibiting phosphodiesterase type 5 (PDE5), an enzyme that breaks down cyclic guanosine monophosphate (cGMP) in the smooth muscle cells of penile blood vessels [1]. When sexual stimulation occurs, nitric oxide is released in the corpus cavernosum, triggering cGMP production. By blocking PDE5, sildenafil allows cGMP levels to remain elevated, promoting smooth muscle relaxation and increased blood flow to the penis.

This mechanism means Viagra does not cause automatic erections — sexual arousal is still required for the medication to work effectively [1]. The drug essentially amplifies your body's natural erectile response rather than creating an artificial one. Clinical trials demonstrate that sildenafil significantly improves erectile function scores across all severities of ED, with approximately 70-80% of men reporting improved erections [2].

How Long Does Viagra Take to Work?

Sildenafil typically begins working within 30-60 minutes after oral administration, though this timeline can vary based on individual factors [1]. Taking Viagra on an empty stomach generally produces faster results, as high-fat meals can delay absorption by up to an hour. Peak plasma concentrations are reached approximately 60 minutes after dosing in most patients.

The effects of Viagra last for approximately 4-6 hours, though this does not mean you will have an erection for this entire duration [2]. Rather, during this window, you will find it easier to achieve and maintain an erection when sexually aroused. Some men report residual effects up to 8-12 hours after taking the medication, though effectiveness gradually diminishes over time.

Optimising Viagra's Effectiveness

To maximise how Viagra works, take the tablet 60 minutes before anticipated sexual activity on an empty stomach or after a light meal. Avoid excessive alcohol consumption, as this can impair erectile function and reduce sildenafil's effectiveness [3]. Starting with the 50mg dose allows your prescriber to adjust upward to 100mg or downward to 25mg based on your response and any side effects experienced.

Viagra Dosage: Finding Your Optimal Strength

Sildenafil is available in three strengths: 25mg, 50mg, and 100mg tablets. The standard starting dose recommended by NICE guidance is 50mg, taken approximately one hour before sexual activity [4]. Your UK prescriber may adjust this based on your response — if 50mg proves insufficient, the dose can be increased to 100mg, or reduced to 25mg if you experience side effects.

The maximum recommended dosing frequency is once per 24-hour period. Taking more than the prescribed dose does not enhance effectiveness and significantly increases the risk of adverse effects such as headaches, flushing, and visual disturbances [4]. At Cured Pharmacy, our clinical team assesses your medical history, current medications, and cardiovascular health to determine the safest and most effective dose for your individual circumstances.

Treatment Active Ingredient Duration of Action Starting Price
Sildenafil Sildenafil citrate 4-6 hours From £0.45
Tadalafil Tadalafil Up to 36 hours From £9.99
Viagra Connect Sildenafil citrate 4-6 hours From £11.49
Cialis Tadalafil Up to 36 hours From £53.00

Viagra vs Cialis: Understanding Your Treatment Options

While both Viagra (sildenafil) and Cialis (tadalafil) are PDE5 inhibitors that work through similar mechanisms, they differ significantly in their pharmacokinetic profiles [5]. Sildenafil has a shorter half-life of approximately 4 hours, making it ideal for planned sexual activity. Tadalafil, by contrast, remains active for up to 36 hours, offering greater spontaneity.

The choice between sildenafil and tadalafil often depends on lifestyle preferences and sexual activity patterns. Men who engage in sexual activity less frequently may prefer sildenafil's shorter duration, whilst those seeking more flexibility often opt for tadalafil [5]. Both medications demonstrate comparable efficacy in clinical trials, with success rates of 70-85% across ED severity grades.

Which PDE5 Inhibitor Is Right for You?

Your UK prescriber will consider several factors when recommending between sildenafil and tadalafil, including your sexual activity frequency, timing preferences, any existing medical conditions, and potential drug interactions. Some men trial both medications to determine which suits their lifestyle and produces the most favourable side effect profile. At Cured Pharmacy, we offer both sildenafil from £0.45 and tadalafil from £0.45, ensuring accessible options regardless of which treatment proves most suitable.

Common Side Effects and Safety Considerations

The most frequently reported side effects of sildenafil include headaches (affecting approximately 16% of users), facial flushing (10%), dyspepsia (7%), and nasal congestion (4%) [2]. These effects are generally mild to moderate and diminish with continued use. Visual disturbances, such as blue-tinged vision or increased light sensitivity, occur in approximately 3% of men taking higher doses.

Serious adverse effects are rare but require immediate medical attention. Priapism — a persistent erection lasting more than 4 hours — occurs in less than 0.1% of cases but constitutes a medical emergency [3]. Sildenafil is contraindicated in men taking nitrate medications for angina, as the combination can cause dangerous drops in blood pressure. Your Cured Pharmacy prescriber will review your full medication list during the clinical assessment to identify any potential interactions.

Getting Viagra Through Cured Pharmacy

Accessing ED treatment through Cured Pharmacy begins with a free online consultation that takes under 3 minutes to complete. Our UK-registered prescribers review your medical history, current medications, and cardiovascular health to determine whether sildenafil is safe and appropriate for you. All consultations are conducted by GPhC-registered clinicians, ensuring you receive the same standard of care as an in-person GP appointment.

Once approved, your prescription is dispensed by our UK-registered pharmacy (GPhC 9012511) and delivered in 100% discreet packaging. We offer genuine UK-licensed sildenafil from £0.45 per tablet, with transparent pricing displayed before you begin the consultation. Our superintendent pharmacist, Tarun Kumar (GPhC 2233073), oversees all clinical services to ensure compliance with MHRA and GPhC standards. If you have questions about your treatment, our pharmacy team is available on (+44) 116 4646009.

Why Choose Cured Pharmacy for ED Treatment

Cured Pharmacy guarantees the lowest prices in the UK for genuine, licensed ED medications. Unlike some online services, we display exact pricing before you complete the consultation, with no hidden fees or subscription requirements. Our clinical team includes experienced UK prescribers who specialise in men's health, providing personalised treatment recommendations based on your individual circumstances. All medications are sourced directly from licensed UK wholesalers and stored in our GPhC-registered facility, ensuring you receive authentic treatments that meet MHRA quality standards.

Scientific References

  1. Goldstein, I., Lue, T. F., Padma-Nathan, H., Rosen, R. C., Steers, W. D., & Wicker, P. A. (1998). Oral sildenafil in the treatment of erectile dysfunction. New England Journal of Medicine, 338(20), 1397-1404. https://doi.org/10.1056/NEJM199805143382001
  2. Carson, C. C., & Lue, T. F. (2005). Phosphodiesterase type 5 inhibitors for erectile dysfunction. BJU International, 96(3), 257-280. https://doi.org/10.1111/j.1464-410X.2005.05614.x
  3. Montorsi, F., Adaikan, G., Becher, E., Giuliano, F., Khoury, S., Lue, T. F., ... & Wasserman, M. (2010). Summary of the recommendations on sexual dysfunctions in men. Journal of Sexual Medicine, 7(11), 3572-3588. https://doi.org/10.1111/j.1743-6109.2010.02062.x
  4. National Institute for Health and Care Excellence. (2024). Erectile dysfunction: Sildenafil. NICE British National Formulary. https://bnf.nice.org.uk/drugs/sildenafil/
  5. Yuan, J., Zhang, R., Yang, Z., Lee, J., Liu, Y., Tian, J., ... & Lyseng-Williamson, K. A. (2013). Comparative effectiveness and safety of oral phosphodiesterase type 5 inhibitors for erectile dysfunction: a systematic review and network meta-analysis. European Urology, 63(5), 902-912. https://doi.org/10.1016/j.eururo.2013.01.012

Information on this page is for educational purposes only and is not medical advice. All prescription treatments require clinical assessment by a UK-registered prescriber. Always consult a qualified healthcare professional before starting any new medication.

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Faq

How does Viagra work in the body?
Viagra inhibits the PDE5 enzyme, allowing increased blood flow to the penis during sexual arousal by maintaining elevated cGMP levels in penile smooth muscle cells. Sexual stimulation is still required for the medication to produce an erection.
How long does it take for Viagra to work?
Sildenafil typically begins working within 30-60 minutes, with peak effectiveness around 60 minutes after administration. Taking it on an empty stomach may produce faster results compared to after high-fat meals.
How long do the effects of Viagra last?
The effects of Viagra last approximately 4-6 hours in most men, during which time achieving and maintaining erections becomes easier with sexual arousal. Some residual effects may persist up to 8-12 hours, though effectiveness gradually diminishes.
What is the correct Viagra dosage?
The standard starting dose is 50mg, taken approximately one hour before sexual activity. Your prescriber may adjust this to 25mg or 100mg based on effectiveness and tolerability, with a maximum of one dose per 24 hours.
Does Viagra work without sexual arousal?
No, Viagra requires sexual stimulation to work effectively. The medication enhances your body's natural erectile response but does not cause automatic erections without arousal.
What are the common side effects of Viagra?
The most common side effects include headaches (16%), facial flushing (10%), indigestion (7%), and nasal congestion (4%). These are typically mild and often diminish with continued use.
How does Viagra compare to Cialis?
Both are PDE5 inhibitors with similar efficacy, but Viagra lasts 4-6 hours whilst Cialis remains active for up to 36 hours. The choice depends on your sexual activity patterns and preference for spontaneity versus planned intimacy.
Can I get Viagra without seeing a doctor?
Viagra is a prescription-only medication in the UK and requires clinical assessment by a UK-registered prescriber. Cured Pharmacy offers a free online consultation under 3 minutes, providing the same standard of care as an in-person appointment.