The doctors not only prescribe the pharmaceuticals to their own patients, they also speak to patient groups and other doctors about those medications.
In return, the drug companies pay them. They have become important ambassadors for the drug companies, with the increasing number of drugs on the market each year. With their high patient loads, doctors increasingly rely on these "speakers bureaus, because they often have little time to personally research the new medications.
Pro Publica, a public interest journalists group, has now researched and published a list of the top recipients of those dollars.
It gathered the names through public records. Reporters say many of those records were confusing, and hard to decipher.
The group's investigation concludes that fewer than half of the top "speakers" are at major teaching or research centers, or leaders in their specialty's medical societies. And the reporters had a hard time finding information on the credentials of some of them.
43 of the 394 doctors on the ProPublica list earned more than $200,000 from the companies.
You can look at the entire list at ProPublica Dollars For Docs database.