If you are thinking about using tadalafil please discuss it with your doctor. The FDA has also approved tadalafil for treatment of both benign prostatic hypertrophy and erectile dysfunction where the two conditions co-exist. How can I buy tadalafil? One advantage Cialis has over Viagra and Levitra is its Your doctor will discuss the best treatment plan for you.Cialis is available only by prescription. It’s not available over the counter. Generally, Medicare does not cover Cialis, since it’s not considered medically necessary. Do Cialis side effects vary based on whether I’m taking a high or low dose ( mg, 5 mg, 10 mg, or 20 mg)? Yes, side effects caused by Cialis can vary depending on the strength you’re taking.