Viagra (sildenafil) is classified as a Prescription Only Medicine (POM) in the United Kingdom. Legally, you cannot purchase authentic Viagra without a valid prescription from a qualified healthcare professional. Despite widespread marketing claiming “cheap Viagra without prescription” or “order Viagra online without prescription,” reputable UK pharmacies such as Elstree Pharmacy require either a physical or electronic prescription before dispensing branded or generic sildenafil. Medicines supplied without a prescription may come from unregulated or potentially unsafe sources, increasing the risk of counterfeit products, incorrect dosing, harmful ingredients, or contamination. If you encounter offers of “buy cheap Viagra online without prescription,” exercise caution: these supplies often bypass essential safety checks and professional counselling. At Elstree Pharmacy, we prioritise patient safety and compliance with MHRA regulations. Our online service enables you to securely order Viagra only after providing a valid prescription, ensuring quality, authentic generic or branded sildenafil, appropriately packaged, and accompanied by professional advice and support. For patients seeking an easily accessible route, speak to your GP or use a registered online clinic that can issue a prescription following an appropriate assessment of your medical history, current medications, and any potential contraindications.
In the UK, human medicines are regulated under three main supply categories:
Viagra (sildenafil) is a POM, meaning it must be supplied against a valid prescription. Some generic alternatives are also POM. The classification ensures that patients receive professional assessment, counselling on correct use, awareness of contraindications, and identification of possible interactions. The term “over the counter” informally refers to medicines that do not require a prescription, but this does not automatically equate to GSL status. For P medications, including certain non-prescription PPIs and emergency contraception, you must consult a pharmacist who may refuse supply if the medicine is deemed inappropriate. Always verify classification before attempting to order medicine online.
Viagra is the brand name for sildenafil citrate, a pharmaceutical agent primarily used to treat erectile dysfunction (ED) in men. Developed by Pfizer and first approved in 1998, Viagra represents the first globally recognised therapy for ED and remains extensively prescribed.
Sildenafil is the active pharmaceutical ingredient. It belongs to a class of drugs known as phosphodiesterase type 5 (PDE5) inhibitors. Generic versions containing sildenafil citrate have been authorised after Pfizer’s original patent expired, enabling more affordable options.
By modulating molecular pathways that regulate smooth muscle relaxation in penile tissue, sildenafil facilitates increased blood flow during sexual stimulation. This enables the achievement and maintenance of an erection sufficient for satisfactory sexual performance in patients diagnosed with ED.
While branded Viagra and generic sildenafil tablets contain the same active ingredient and strength, inactive ingredients, tablet shape, colour, packaging, and excipients may differ. All authorised products must meet rigorous regulatory standards for quality, efficacy, and safety.
Sildenafil is also approved under other brand names (e.g., Revatio) for pulmonary arterial hypertension (PAH) at different dosage regimens. This article focuses on ED indications and UK supply.
Sildenafil inhibits the enzyme phosphodiesterase type 5 (PDE5) in smooth muscle cells of the corpus cavernosum. PDE5 normally degrades cyclic guanosine monophosphate (cGMP), a messenger that causes smooth muscle relaxation when elevated.
During sexual stimulation, nitric oxide (NO) is released in the corpus cavernosum, activating guanylate cyclase, which raises cGMP levels. Sildenafil enhances and prolongs this cGMP-mediated relaxation, allowing increased arterial blood flow into erectile tissue and resulting in an erection.
No. Sexual stimulation is required to initiate NO release. Sildenafil alone does not trigger an erection without sexual arousal.
Onset of action typically occurs within 30 to 60 minutes after oral administration, depending on factors such as food intake, dosage, age, and individual response.
Plasma concentrations decline over 4 to 6 hours, and most patients can achieve satisfactory erections within this window. Variability exists, and some individuals may experience shorter or longer durations.
Prices vary by brand, generic manufacturer, pack size, strength, and retailer. Branded Viagra 50 mg tablets typically cost more than generic sildenafil 50 mg. This section provides indicative pricing for comparison; current prices should be confirmed with Elstree Pharmacy.
Factors influencing price include patent expiry, manufacturer discounts, bulk purchasing, distribution agreements, pack presentation, and retailer promotions. Generic sildenafil can deliver significant savings while maintaining quality and efficacy.
| Product | Strength | Pack Size | Approximate Price | Status | Note |
|---|---|---|---|---|---|
| Branded Viagra | 50 mg | 4 tablets | £30–£40 | POM | Prescription required |
| Generic sildenafil A | 50 mg | 4 tablets | £10–£15 | POM | Ask Elstree Pharmacy for current price |
| Generic sildenafil B | 100 mg | 4 tablets | £15–£20 | POM | Higher dose option |
For the latest availability, offers on bulk packs, price-match or discount coupons, please contact the Elstree Pharmacy team directly.
ED formulations of sildenafil are commonly available in 25 mg, 50 mg and 100 mg strengths. The choice depends on clinical assessment, patient tolerance, and efficacy response.
Tablets are the standard oral form. Some products may have film-coated or dispersible tablet variations for patients with swallowing difficulties. The brand or generic name determines the coating and excipients used.
Regulatory classification is linked to pack size. Bulk packs of generic sildenafil may be supplied as POM with a larger maximum quantity, but the patient’s prescription specifies the number of tablets authorised.
Switching from branded Viagra to generic sildenafil is generally acceptable if the dose is equivalent. Pharmacists can advise on bioequivalence and possible differences in appearance or excipients.
Film coating helps protect the tablet, mask bitterness, and aid swallowing. All coated tablets must dissolve appropriately to release active drug in the gastrointestinal tract.
ED is the inability to achieve or maintain an erection sufficient for satisfactory sexual performance. It can have physical, psychological, neurological or vascular causes, often overlapping.
ED prevalence increases with age but can affect men of all ages. Common risk factors include cardiovascular disease, diabetes, hypertension, obesity, smoking, and certain medications.
Diagnosis typically involves medical history, symptom enquiry, physical examination, and selective laboratory tests. Psychological assessment may also be relevant.
Sildenafil is indicated for men with ED of organic, psychogenic or mixed origin. It may be used when ED interferes with quality of life and after appropriate evaluation by a healthcare professional.
Take sildenafil approximately one hour before sexual activity on an empty stomach or after a light meal. Do not exceed one dose per 24 hours. Follow dose adjustments as advised by your prescriber.
A Prescription Only Medicine requires a valid prescription from an authorised healthcare professional. Supply without such a prescription is illegal and unregulated.
No. Sildenafil remains POM in the UK, regardless of dose or pack size. Unlike some emergency contraceptives or low-dose PPIs, there is no non-prescription route for sildenafil.
Classification ensures patient safety by requiring professional oversight, proper diagnosis, dosage selection, monitoring of side effects, and checking for contraindications and interactions.
The Medicines and Healthcare products Regulatory Agency (MHRA) oversees classification, supply regulations, and enforcement to protect public health.
Lifestyle changes (weight loss, smoking cessation, pelvic floor exercises), vacuum erection devices, penile implants and psychological counselling may form part of an integrated management plan.
Alternatives may be chosen based on duration requirements, side effect profiles, ease of dosing, comorbid conditions, or previous response to treatment.
Sildenafil’s effective window spans approximately 4–6 hours. Tadalafil offers up to 36 hours of efficacy but may cause muscle aches more frequently.
Vardenafil has a similar duration to sildenafil but is sometimes better tolerated for specific patients. Dosage strength differs.
Avanafil has one of the fastest onsets (15–30 minutes) and a duration of about 6 hours. It may be preferred by patients seeking spontaneity.
| Feature | Sildenafil | Tadalafil | Avanafil |
| Drug class | PDE5 inhibitor | PDE5 inhibitor | PDE5 inhibitor |
| Onset | 30–60 min | 30–120 min | 15–30 min |
| Duration | 4–6 hrs | 24–36 hrs | 6–12 hrs |
| Prescription status UK | POM | POM | POM |
No. The choice of PDE5 inhibitor depends on individual patient preference, side effect profile, comorbidities, drug interactions and cost considerations.
A high-fat meal can delay absorption, reducing and delaying peak plasma levels. Taking sildenafil on an empty stomach or after a light meal is generally recommended.
Excessive alcohol consumption can impair erectile response, counteract therapeutic benefit, and increase side effect risks such as dizziness and low blood pressure.
Smoking contributes to vascular disease, which is a major cause of ED. Quitting smoking can improve overall vascular health and erectile function.
Obesity is a risk factor for ED. Weight management, exercise and healthy diet can improve response to pharmacological therapies.
Yes. Side effects range from mild to severe. Most are transient and resolve without intervention. Serious adverse reactions are rare but require prompt medical attention.
| Area | Examples |
| Cardiovascular | Flushing, palpitations, hypotension |
| Nervous system | Headache, dizziness |
| Visual | Blurred vision, changes in colour perception |
| Gastrointestinal | Dyspepsia, nausea |
| Musculoskeletal | Myalgia, back pain |
| Hypersensitivity | Rare severe allergic reactions |
Stop sildenafil and seek immediate medical care if you experience chest pain, sudden vision loss, priapism (erection >4 hours), severe dizziness or allergic signs.
Sildenafil can be used as needed up to once daily. Daily dosing regimens may be considered under specialist guidance but require monitoring.
Frequent high doses can increase risk of side effects, particularly cardiovascular or ocular events. Adherence to prescribed dose and frequency is essential.
Ongoing use for more than six months should prompt a review of efficacy, side effects, and any emerging health concerns by a healthcare professional.
Yes. Notable interactions include:
Professional assessment ensures safe integration of sildenafil with existing therapies and underlying health conditions, minimising the chance of adverse interactions.
A generic medicine contains the same active substance as the branded reference medicine (Viagra) and meets identical regulatory standards for quality, safety and efficacy. Generic tablets may differ in appearance and excipients.
Price differences among generic sildenafil products reflect manufacturer costs, brand recognition, distribution agreements, and retailer promotions.
Obtain Sildenafil only from MHRA-licensed pharmacies. Check packaging, batch numbers, expiry dates, and information leaflets. Avoid unverified online sources offering “no prescription” deals.
Consult the MHRA website, electronic Medicines Compendium (eMC), British National Formulary (BNF), and qualified healthcare professionals for official guidance on sildenafil products.
No. This article provides general information from Elstree Pharmacy (The Corner Shop B, High Street, Elstree, WD6 3BY). For personalised advice or clinical inquiries, please speak with our pharmacy team or your GP.
