Summary Cialis and Viagra are both pills for treating erectile dysfunction. BUT be careful — like tadalafil, vardenafil, and other phosphodiesterase type 5 inhibitors, Viagra should be prescribed and taken under the medical advice of a healthcare professional. Talk with your healthcare provider about which might be best for you. The survival rate is now 80 per cent, but it could be higher. However, the dosage can range from 25— mg. Stop taking VIAGRA and call your healthcare provider right away if you have any sudden vision loss sudden hearing decrease or hearing loss. Viagra generally only stays in your system for four to six hours.Find a Walgreens store near you. Your go-to for Pharmacy, Health & Wellness and Photo products. Refill prescriptions online, order items for delivery or store pickup, and create Photo Gifts. 7 Over The Counter Medications for ED. Depending on the cause of erectile dysfunction, the most effective treatment can vary. Typically, the best way to treat erectile dysfunction is to address the underlying cause. Second is by using oral medications like Viagra® (sildenafil), Cialis® (tadalafil), or Levitra® (vardenafil), all of which are.