Viagra is used when treating male erection problems. Take it orally with a glass of water. The dose is usually taken 1 hour before sexual activity.
Cialis is used for the treatment of male erection problems. It is also currently undergoing Phase 3 of clinical trials for the treatment of pulmonary arterial hypertension.
Levitra is used for the treatment of men’s erection problems. It works faster than Sildenafil (Viagra®) and it has lower chance to cause visual disturbance side effect.