Of course, bear in mind the currently corrupt organizations putting out the following information (ie heavily promoting DTC in the case of NIH). Nonetheless there's a trove of good information on the history of DTC here.
"... Direct-to-consumer (DTC) advertising is a relatively new area of prescription drug promotion. No federal law has ever banned DTC advertising. Until the mid-1980s, drug companies gave information about prescription drugs only to doctors and pharmacists. When these professionals thought it appropriate, they gave that information to their patients. However, during the 1980s, some drug companies started to give the general public more direct access to this information through DTC ads ..."
Of course, bear in mind the currently corrupt organizations putting out the following information (ie heavily promoting DTC in the case of NIH). Nonetheless there's a trove of good information on the history of DTC here.
https://pmc.ncbi.nlm.nih.gov/articles/PMC3278148/
.
From the FDA website --
"... Direct-to-consumer (DTC) advertising is a relatively new area of prescription drug promotion. No federal law has ever banned DTC advertising. Until the mid-1980s, drug companies gave information about prescription drugs only to doctors and pharmacists. When these professionals thought it appropriate, they gave that information to their patients. However, during the 1980s, some drug companies started to give the general public more direct access to this information through DTC ads ..."
https://www.fda.gov/drugs/prescription-drug-advertising/background-drug-advertising