Viagra was the drug that changed the world in 1998 and revolutionised treatment for men with erectile dysfunction (ED). Cialis was the second ED drug brought to market and earned the nickname The Weekend Pill as it’s duration of action is 36 hours (Viagra lasts for 4 hours). Other tablets to treat ED are Levitra and Spedra.
Viagra has been ‘off patent’ since 2013 which means legal copies of the drug can now be sold in the UK as generics called sildenafil, and there are now many brands of sildenafil available. The patent for Cialis expired November 2017 and lower cost generic Tadalafil is also now available.
Both treatments are available on prescription only following an erectile dysfunction consultation.
Compare Viagra and Cialis
Studies suggest patients and their partners have a preference for tadalafil (Cialis) over sildenafil (Viagra) for the treatment of erectile dysfunction.
| Viagra | Cialis | |
|---|---|---|
| Chemical name | Sildenafil | Tadalafil |
| Starting dose | 50mg | 10mg |
| Low dose | 25mg | 2.5mg–5mg |
| Maximum dose | 100mg | 20mg |
| Onset time | 40 minutes | 30 minutes |
| Duration of action | 4 hours | 36 hours |
| Common side effects | Headache, palpitation, indigestion, dizziness, congestion, flushing, blurred vision | Headache, muscle pain, indigestion, congestion, flushing, dizziness |
| Cautions and interactions | Any nitrate-based medication, low blood pressure, retinitis pigmentosa, recent myocardial infarction, angina | Any nitrate-based medication, low blood pressure, recent myocardial infarction, angina |
| Patient leaflet | View PDF | View PDF |
| UK patent | Expired June 2013 | Expires November 2017 |
| Branded price | From £5.13 per tablet | From £2.29 per tablet |
| Generic price | From 97 per tablet | From 82p per tablet |
| Available on NHS | Yes as generic sildenafil (usually 4 tablets per month) | Not usually |