Drug company promotion negatively affects how doctors prescribe: Insights from a new Cochrane review

When you seek medical care, you hope that your doctor will present you with treatment options that are proven to be effective for your condition, that harms do not outweigh benefits and that recommended treatments are affordable and account for your personal situation.

But if your doctor has been influenced by messages, payments or gifts from drug companies, that is unlikely to be the case, as our team from Australia, Canada, the United Kingdom and the United States found.

Pharmaceutical industry promotion is a global phenomenon.

In the mid 2010s, companies in the U.S. spent just under US$30 billion annually to convince doctors to prescribe their products.

Figures in other countries are harder to come by but in the mid 2010s, close to CA$500 million was being spent in Canada on advertising in medical journals and on sales representatives who visit doctors’ offices.

Between 2015 to 2024, 17,519 Australian doctors received AU$148.7 million from pharmaceutical companies for conferences, travel costs or consultancy fees.

In 2020, seven of the top 10 largest pharmaceutical companies globally spent more on marketing than on developing new drugs .

Our research examines the relationship between pharmaceutical promotion and doctors’ prescribing.

Evidence shows the effects of promotion Our Cochrane systematic review looked at the results of 93 studies involving millions of doctors and published largely over the past two decades.

Due to their rigour, Cochrane reviews are considered the gold standard for evidence synthesis.

We examined what happens to the appropriateness, quantity and cost of prescriptions when doctors accept payments or meals from the pharmaceutical industry or rely on pharmaceutical representatives for their education or prescribing information.

We looked at the effects of a range of types of promotion: advertising and industry-sponsored education, gifts such as free meals and payments for consulting or advisory board membership and free drug samples.

The result is not good news for patients.

Doctors who receive gifts or payments prescribe less appropriately and issue more prescriptions — and those prescriptions tend to be more costly.