In 2015, the total amount spent on prescription drugs in the U.S. was $425 billion (12.2% higher than 2014).
In 2015, the total amount spent on OTC (over-the-counter) drugs in the U.S. was $32.1 billion ( a modest 4.6% increase).
It's common knowledge that prescription drugs are more expensive in the U.S. than in other countries. A great article in the Wall Street Journal summarizes the problem: Why The US Pays More Than Other Countries (check out the comparison to Norway).
But did you know that OTC (over-the-counter) medicines such as Tylenol, Zantac, and many others are also more expensive in the U.S.? Probably not. When drugs like Zantac, Allegra, Claritin got approved for OTC, it wound up costing consumers more to use the same drugs than if they were getting the generic prescription version.
Even commonplace medications such as Tylenol cost more in the U.S. Why? Mostly, the answer is just "because". In other words, Americans are asked to spend more just because the drug companies decided that they should. This is one reason why medical tourism is so high. Sometimes, it's the only way to afford expensive, life-saving, medication. (And don't get me started on the whole Epi-Pen situation.)