Actually, big pharma does both. Marketing to doctors is sometimes even more sinister, because of (often implied) incentives for pushing more of a medication on the physician's patients.

Some resources:

[1] https://www.sciencedaily.com/releases/2018/05/180514132441.h...

[2] https://www.pewtrusts.org/en/research-and-analysis/fact-shee...

Plus, this classic Scrubs clip describing a particularly chauvinistic (but truth-in-television) take on the practice: https://www.youtube.com/watch?v=VMXa0U4WZyU