Doctors don’t have a lot of choice when it comes to prescribing as we’re limited by insurance company formularies. Neither doctors nor patients are the consumers in the United States it’s really the insurance carriers. Until something is put on a formulary, physicians can’t and generally don’t prescribe it. So although drug companies do market generally to physicians and patients with direct to consumer advertising, where the real money is in lobbying the insurance carrier. I’ve been prescribing drugs for 20 years, and I get drug company ads in my mailbox all the time. But I really doubt that any of those ads, which are junk mail, are the result of my prescribing habits (which are mandated by whatever formulary the patient has which for me, fortunately working in a public health care system, are few).

That said, no question there are certainly insidious practices by drug companies, not the least of which are hiring doctors to create markets for drugs. Probably the most notorious example is the drug gabapentin or Neurontin. Gabapentin is an antiepileptic, but it’s a crappy anti-seizure drug and there were way better and cheaper ones out there (like the old standby dilantin). Pfizer needed to figure out a use for it. So they did a huge market campaign hiring a bunch of doctors to “educate” physicians in off label use of gabapentin for peripheral neuropathic pain, and it was HUGELY successful. It’s still used quite frequently and although it’s gone generic, it’s become a standard treatment. All because Pfizer had this drug sitting on their shelf they couldn’t sell. Here is a source. http://en.wikipedia.org/wiki/Off-label_use