Levitra (generic version vardenafil) is common erectile dysfunction treatment. Similar to the other PDE-5 inhibitors, vardenafil is taken as needed before sexual activity and comes in four doses (2.5 mg, 5 mg, 10 mg, and 20 mg). Here’s more on what you need to know about vardenafil, its primary uses, and what side effects to be aware of before taking the drug.