Earlier this year the Washington Post did a nice job of outlining how big pharmaceutical companies actually spend their money. The WP's motivation was two-fold.
First, the biggest pharmaceuticals were arguing that drug prices are high because they spend so much on the research and development (R&D) of drug products. Second, HBO's John Oliver did a great job of highlighting how the pharmaceutical industry actually spends their money marketing.
I encourage you to read the WP piece, but the results of their report are pretty much summarized in the bubble graph below.
You can check out John Oliver's piece on the pharmaceutical industry's marketing policies by clicking here, or by watching the YouTube video below.