Are senior doctors who help drug companies sell their drugs independent experts or just drug representatives in disguise, asks Ray Moynihan from the University of Newcastle in Australia, in this week's BMJ.

Pharmaceutical companies regularly sponsor leading specialists with "generous fees to peddle influence" and promote drugs to the profession and the public, writes Moynihan.

Drug companies will pay influential doctors up to $400 an hour to act as key opinion leaders, and some doctors earn more than $25 000 a year in advisory fees.

Kimberly Elliot, a former award-winning drug company sales representative interviewed by Moynihan, says that drug companies desperately need key opinion leaders in order for doctors to believe what they are saying and prescribe their products, because drug representatives are often not believed. Essentially, she says, key opinion leaders are also salespeople.

So how independent are these doctors who have long term financial arrangements with drug companies?

According to Richard Tiner, medical director at the Association of the British Pharmaceutical Industry, although "the work might help to promote a particular medicine" it should be considered payment for work done, and not a bribe. The best antidote to concerns about independence would be more transparency—all company payments to speakers should be routinely disclosed at medical meetings, he adds.

But David Blumenthal, from Harvard University, believes that payments to key opinion leaders are not in the public interest or in the interests of the patients served by these doctors, and calls for a major cutback in industry influence over the medical profession and its education.

In an accompanying head to head, Charlie Buckwell, Chief Executive of the Complete Medical Group and Professor Giovannii Fava, from the University of Bologna, debate whether drug companies' use of medical experts is essential for medical advancement or whether it risks scientific integrity.