On average, it can take between 30 and 60 minutes to activate. Boosting Psychological Well-being Beyond the physical realm, the emotional benefits of Cialis can’t be ignored. In a report from , researchers describe a patient who experienced sudden loss of hearing after using vardenafil to treat erectile dysfunction. Journal of Clinical Pharmacology and Therapeutics, 44 05 , — Clinical Interventions in Aging, 1 4 , —Vision changes. Muscle pain. But there are some differences. With Viagra, there is a higher risk of vision changes than with Cialis. Among people who take Viagra or sildenafil, 3% get blue vision that lasts a few hours. On the other hand, Cialis has a slightly higher risk of muscle pain than Viagra and vardenafil. Find patient medical information for Levitra oral on MD including its uses, side effects and safety, interactions, pictures, warnings and user ratings. You shouldn’t take more than one dose (typically 10 mg) of vardenafil per day. Taking too much can lead to dangerous side effects, like low blood pressure and vision problems. If you don’t think vardenafil is working well for you, speak to your provider. They might be able to adjust your dose or change you to a different medication.