VIAGRA VS CIALIS VS LEVITRA VS STENDRA
Viagra vs Cialis vs Levitra vs Stendra: Which ED Medication Is Right for You?
Medical disclaimer: This article is for informational purposes only. ED treatments are prescription-only medicines. Always complete a clinical consultation before use. Our prescribers are GPhC-registered pharmacist independent prescribers.
Viagra (sildenafil), Cialis (tadalafil), Levitra (vardenafil), and Stendra (avanafil) are the four main MHRA-approved oral medications for erectile dysfunction (ED) available in the UK. All four belong to the same drug class — phosphodiesterase type 5 (PDE5) inhibitors — and work through the same mechanism. However, there are important differences in how quickly they work, how long they last, and their side effect profiles. Understanding these differences helps you and your prescriber choose the most suitable option.
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Start Your Consultation →✓ GPhC-registered pharmacy #9011198 ✓ Pharmacist independent prescribers ✓ Discreet next-day deliveryHow PDE5 Inhibitors Work
All four medications inhibit an enzyme called phosphodiesterase type 5 (PDE5), which regulates blood flow in the penis. By blocking PDE5, these drugs allow the smooth muscle in penile blood vessels to relax more easily when sexually stimulated, enabling increased blood flow into the erectile tissue and facilitating an erection.
Important: PDE5 inhibitors do not cause erections on their own — sexual stimulation is still required. They enhance the body’s natural erectile response rather than bypassing it.
Comparison of All Four ED Medications
| Medication | Active Ingredient | Onset | Duration | Affected by Food? | Key Notes |
|---|---|---|---|---|---|
| Viagra | Sildenafil | 30–60 min | 4–6 hours | Yes — avoid large fatty meals | Most well-known; generic sildenafil available and equivalent |
| Levitra | Vardenafil | 25–60 min | 4–6 hours | Mildly | May work slightly faster than Viagra in some men |
| Cialis | Tadalafil | 30 min | Up to 36 hours | No | ‘Weekend pill’; also available as 5mg daily for continuous use |
| Stendra/Spedra | Avanafil | 15–30 min | Up to 6 hours | Minimal | Fastest onset of the four; newer agent |
Side Effects — What They Have in Common
As all four are PDE5 inhibitors, their side effect profiles are similar. Common side effects include:
- Headache
- Flushing of the face
- Nasal congestion
- Indigestion or stomach discomfort
- Dizziness
- Temporary visual changes (most common with sildenafil — slight blue tinge to vision)
Specific Side Effect Differences
| Medication | Notable Side Effects |
|---|---|
| Sildenafil (Viagra) | Flushing, stomach pain, headache; visual disturbances more common than with other agents |
| Tadalafil (Cialis) | Back pain and muscle aches (due to longer duration); low blood pressure with antihypertensives |
| Vardenafil (Levitra) | QT prolongation risk — not for use with certain cardiac medications; avoid in long QT syndrome |
| Avanafil (Stendra/Spedra) | Flushing, headache; rare priapism (seek care if erection >4 hours) |
Important Interactions — All Four Medications
- Nitrate medicines (glyceryl trinitrate, isosorbide mononitrate) — absolute contraindication; dangerous blood pressure drop
- Alpha-blockers — used for prostate or blood pressure; combination can lower blood pressure significantly
- Blood pressure medications — additive hypotensive effect; discuss with prescriber
- Grapefruit juice — affects drug metabolism; avoid with all four
- CYP3A4 inhibitors — certain antibiotics (clarithromycin) and antifungals (ketoconazole) increase drug levels
Access Doctor’s Range of ED Medications
Access Doctor stocks all major MHRA-approved ED medications including Viagra (sildenafil), Cialis (tadalafil), Spedra (avanafil), Levitra (vardenafil), and their generic equivalents. Our pharmacist independent prescribers will guide you on the most suitable choice based on your health history and preferences. For a detailed look at two of the most popular options, see our guide to tadalafil vs sildenafil.
When to seek urgent care: Seek immediate medical attention if you experience an erection lasting more than 4 hours (priapism), sudden vision loss, or sudden hearing loss after taking any ED medication. These are rare but require emergency treatment.
More Erectile Dysfunction Guides from Access Doctor
- ED: The Basics
- Kamagra Dangers: Why It’s Unsafe and What to Use Instead
- What Causes Erectile Dysfunction?
- What is Viagra? Your Complete Guide to Sildenafil
- Can Surgery Cause Erectile Dysfunction?
- Lifestyle Changes for Erectile Dysfunction
- Erectile Dysfunction in Young Men
- Tadalafil vs Sildenafil: Which is Better?
- What to Expect When Taking Viagra for the First Time
- Understanding and Overcoming Erectile Dysfunction
- Is Erectile Dysfunction Treatment Guaranteed?
- How to Know You May Have Erectile Dysfunction
Frequently Asked Questions
What is the difference between Viagra, Cialis, Levitra, and Stendra?
All four are PDE5 inhibitors that treat ED by increasing blood flow to the penis. The key differences are duration of action: Viagra (4–6 hours), Levitra (4–6 hours), Stendra/Spedra (up to 6 hours), and Cialis (up to 36 hours — making it the ‘weekend pill’). Stendra also tends to work fastest at around 15–30 minutes.
Which ED medication is strongest?
All four medications have comparable effectiveness for most men. Clinical studies show similar efficacy rates (80–85% success in achieving erections). The ‘best’ medication depends on individual factors including how quickly you want it to work, how long you need it to last, and your tolerance of side effects.
Can I drink alcohol with ED medication?
Small amounts of alcohol are generally considered acceptable with ED medication, but larger quantities can impair the ability to achieve an erection and increase side effects such as dizziness, flushing, and low blood pressure. Grapefruit juice should be avoided as it affects drug metabolism.
Are these ED medications safe with heart conditions?
PDE5 inhibitors must NOT be combined with nitrate medicines (prescribed for angina or chest pain) as this can cause a dangerous drop in blood pressure. If you have a heart condition, your prescriber will assess whether ED medication is appropriate. Men who are advised to avoid sexual activity due to cardiovascular risk should not take these medications.
Do I need a prescription for Viagra in the UK?
Since 2017, men in the UK can purchase a limited supply of sildenafil (Viagra Connect) without a full prescription from a pharmacy following a brief pharmacist consultation. However, for full prescribing flexibility (all doses and brands), a prescriber consultation via Access Doctor is the safest route.
Which ED medication lasts the longest?
Tadalafil (Cialis) lasts the longest — up to 36 hours — making it the most popular choice for men who prefer not to plan sexual activity around medication timing. Tadalafil is also available as a once-daily low-dose option (5mg daily) for continuous management.
References
- NICE. Erectile dysfunction — management. CKS 2023. cks.nice.org.uk/topics/erectile-dysfunction
- NHS. Erectile dysfunction (impotence). nhs.uk/conditions/erection-problems-erectile-dysfunction
- GPhC. Standards for registered pharmacies. pharmacyregulation.org
- Hatzimouratidis K et al. EAU Guidelines on erectile dysfunction. Eur Urol. 2010. pubmed.ncbi.nlm.nih.gov
- MHRA. Sildenafil (Viagra) — assessment report. gov.uk/mhra
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GPhC-registered online pharmacy. Pharmacist independent prescribers. Leading brands including Viagra (sildenafil), Cialis (tadalafil), Spedra (avanafil), and Levitra (vardenafil). Discreet delivery.
View ED Treatments →✓ GPhC-registered pharmacy #9011198 ✓ Pharmacist independent prescribers ✓ Discreet next-day deliveryAccess Doctor is a GPhC-registered online pharmacy (registration number 9011198). All prescriptions are issued by GPhC-registered pharmacist independent prescribers. Medicines supplied are MHRA-compliant UK-licensed products.
