The main participants:
Pfizer: 101 million prescriptions worth $2.7 billion
Merck: 39 million prescriptions worth $356 million
Wyeth 52 million prescriptions worth $64 million
(Wyeth was acquired by Pfizer)
Abbot: 16 million prescriptions worth $32 million
Of note, different companies accounted differently for prescription value (retail vs. acquisition cost) or prescription unit (per pill or per package).
What do the drug companies get for their samples?
They offer samples for high margin medicines. In most cases, physicians could prescribe lower cost (and therefore higher value) alternatives. Once a patient starts on the high-cost brand name, it's unlikely he or she will switch to a generic.
The two brand name drugs are mentioned in the WSJ article as samples that are often provided by Pfizer and Lilly cost around $5 per day. Generic medications cost as little as 50 cents per day (Source: Drugstore.com.) There is no evidence of increased efficacy of the (expensive) brand name medications.
Many physician offices have eliminated pharmaceutical detailing altogether. Those offices prescribe more generics, and leave their patients with lower overall drug bills. This disclosure, along with disclosure of pharmaceutical and medical device company payments to physicians for consulting and other services, can help drive public policy and ultimately decrease medical trend.