Yes, ED pills can cause side effects. Cialis tadalafil : This ED medication works with the same principle as Viagra, but lasts up to 36 hours. They have the same benefits and risks as their brand-name counterparts. Most online providers require a picture of a valid ID, a selfie showing your face, and a recent blood pressure reading taken with a home blood pressure monitor or by a medical provider. Most erectile dysfunction medications belong to the drug class known as PDE5 inhibitors , which help relax the muscles and increase blood flow to allow for a full erection. Levitra vardenafil : This medication is taken one hour before sex and can last up to 24 hours.Written by Benita Lee, MPH Updated on June 23, Key takeaways: Cialis (tadalafil) is a popular medication used to treat erectile dysfunction. It’s available in tablets ranging from . Sildenafil (Viagra) and tadalafil (Cialis) are the most commonly prescribed medications for ED, and they have the longest track record. For occasional use, most people start with . There are many options and few are one-size-fits-all, so here are our 12 top picks for online pharmacies for specific needs. Our 12 Picks for Online Pharmacies of For Hair .