These are the findings of a systematic review by Dr Geoffrey Spurling from The University of Queensland's School of Medicine, and colleagues from eight other institutions, to be published in this week's PLoS Medicine.
"We found no benefit for doctors from pharmaceutical promotion," Dr Spurling said.
"So doctors need to recognise these tactics and should instead use information sources that are independent of pharmaceutical companies."
The researchers reviewed all the available literature that has looked at information from pharmaceutical companies and how this influences doctors.
They found that in almost all cases studied, information from pharmaceutical companies could be associated with higher prescribing frequency, higher costs, and lower prescribing quality.
For example, one study found that doctors with low prescribing costs were more likely to have rarely or never read promotional mail or journal advertisements from pharmaceutical companies than doctors with high prescribing costs.
However, because most of the studies included in the review were observational studies - the doctors in the studies were not randomly selected to receive or not receive drug company information - it was not possible to conclude that exposure to pharmaceutical information actually caused any changes in physician behaviour.
The study focused on 58 studies and is the first article to exhaustively evaluate all the available literature on this topic.
Pharmaceutical expenditure on promotion totalled $57 billion in the US in 2004.
Pharmaceutical promotion is a controversial topic amongst doctors and this issue is gaining a higher profile in the general public because of the potential conflict of interest it presents to doctors.
As a result of this review Dr Spurling suggests that drug companies should do what they do best - take basic scientific discoveries and turn them into medications.
"If companies want to contribute to medical education then they should put their money into a common pool that would be administered by an independent organisation," Dr Spurling said.
Dr Spurling said that policy makers should devise payment systems that rewarded companies for improving appropriate use of their products rather than for increasing sales.
Regulation of promotion should be overseen by an independent organisation established through legislation.
Finally, policy makers should put significant resources into independent sources of information for prescribers.
