If you were asked to name the best-selling medication in the United States last year, what would your guess be? Not the most prescribed drug, but the medication with the most revenue, mind you. I know what you are thinking — it must be a cardiac drug, due to the prevalence of heart disease. Lipitor? Close, but that would be the lifetime sales king ($141 billion). Maybe a diabetic drug? There are obese people with diabetes everywhere. No, wait, an opioid — that has been in the news all over the place in the last year. Well, the answer is not exactly clear cut, depending on what source you quote. However, it does appear that between July 2013 and June 2014 the best-selling medication in this country was aripiprazole (Abilify), with sales of $7.2 billion, and the most prescribed medication was levothyroxine (Synthroid), with 22.6 million prescriptions written.