| onset of action | duration of action (hours) | doses | |
| sildenafil | 20-30 minutes; peak action 60 minutes | 4-6 | 25-50-100mg | 
| tadalafil | 60-120 minutes; peak action 120 minutes | 36-48 | 10-20mg | 
| vardenafil | 20-30 minutes; peak action 60 minutes | 4-6 | 5-10-20 mg | 
The respective summary of products must be consulted before prescribing any of the drugs mentioned.
Reference:
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