Your point is well taken, and I agree that the burden of any responsibility would be on the pharmacy, doctors etc., not the marketer (you).
However, I don’t think your biggest issue would be with Govt. action, it would more likely come from a private action that would go after anyone associated with it. Even if you were not legally responsible, the costs associated with a defence could be huge.
I’m gonna approach Online Pharmacies with extreme caution and hope I can insulate myself from any liability if and when I start to actively promote them.