First, it is rather ludicrous to suggest the main difference in health care expenditures is linked to the US subsidising medicines. For example, while the US spend 17.1% of GDP in health, the UK spend 9.4 % (http://data.worldbank.org/indicator/SH.XPD.TOTL.ZS). The 8 points of GDP difference represents close to 300 billions $, which would be a significant proportion of the revenue of all the pharmaceutical combined (I did not look much for reliable statistics of combined revenue, but saw that: http://www.statista.com/topics/1764/global-pharmaceutical-in..., which suggests ~1 trillions USD).
It is also well documented that sales are significantly more expensive in the US than in Europe (marketing expenses are higher than R&D for most big pharmaceutical, and that proportion is significantly more so in the US). So without more analysis, you can't say from higher sales whether the US are subsidising European healthcare or marketing departments.
It is also well documented that sales are significantly more expensive in the US than in Europe (marketing expenses are higher than R&D for most big pharmaceutical, and that proportion is significantly more so in the US). So without more analysis, you can't say from higher sales whether the US are subsidising European healthcare or marketing departments.