FDA encourages anyone aware of a serious side effect, including consumers or patients, to make a MedWatch report. Can Cialis be used with other treatments for impotence? Will Cialis be prescription or OTC over-the-counter? If you have an erection that lasts for more than 4 hours, you should go to the nearest hospital emergency department. Prolonged erections can be dangerous.Tadalafil (Generic for Cialis) Tablets · 20mg · 6-day supply With insurance est. $ Estimated insurance price. Final price varies with your insurance. Without insurance $$ Prime member price, 6-day supply. FREE delivery Prescription Required Sildenafil (Generic for Viagra) Tablets · mg · 6-day supply With insurance est. $ Montelukast (Generic for Singulair, Oral Tablet) $ Prime member price, day supply. Insurance price and days’ supply options also available. Free Delivery. FSA or HSA eligible. Prescription required. Escitalopram (Generic for Lexapro, Oral Tablet) $ Cialis and generic tadalafil are available in four different strengths— mg, 5 mg, 10 mg and 20 mg—but which one should you take? If you’ve never tried Cialis before, your doctor will likely start you on a low dose, like mg or 5 mg. The 20 mg tablet is the highest strength and is often not preferred because it has the potential to Missing: amazon.