This is not true anymore, as advertising to patients has been the major driver of growth, perhaps due to Medicare and the rise of expensive biologics, leading to advertising to consumers becoming the predominant sink.
In 2016, pharma companies spent more on direct to consumer ads than they spend on marketing to doctors (excluding free samples, which are somewhere in between, though ultimately the drug being free is really of concern to the patient far more than the doctor), see: https://jamanetwork.com/journals/jama/fullarticle/2720029
In 2016, we have 9.6 billion in direct-to-consumer spending, 13.5 billion in free samples, and 6.8 billion in everything else. So clearly, advertising to consumers is the dominant venue.
In 2016, pharma companies spent more on direct to consumer ads than they spend on marketing to doctors (excluding free samples, which are somewhere in between, though ultimately the drug being free is really of concern to the patient far more than the doctor), see: https://jamanetwork.com/journals/jama/fullarticle/2720029
In 2016, we have 9.6 billion in direct-to-consumer spending, 13.5 billion in free samples, and 6.8 billion in everything else. So clearly, advertising to consumers is the dominant venue.