The doctors making the claims come from US government, universities, hospitals and big pharma. They also say that bad medicines contribute to the growing problem of antimicrobial resistance.
They have called the rise in falsified and substandard medicines a "public health emergency".
The article in The American Journal of Tropical Medicine and Hygiene claims that up to 10% of drugs in low or middle income countries are poor quality or fakes. They claim that this is costing the local economies between US$10bn and US$200bn a year.
The worst drugs are those intended to treat or prevent malaria, pneumonia, hepatitis, yellow fever and meningitis.
The doctors have called for more support for the World Health Organization's (WHO) drug surveillance programme. In addition, they want to see a global treaty on drug quality to obtain evidence on fake drug activities, and provide for extradition so that criminals can be charged.
The WHO recently issued a global alert about a fake cancer drug in Europe and the Americas, which was packaged to look like the drug Iclusig, but actually contained only paracetamol.
Bernard Naughton, an expert in falsified and counterfeit medicines at Oxford University, called fake medicine a "wicked problem" that needed to be tackled by combined effort from pharma, academia, governments, healthcare practitioners and the public.
He said the UK legitimate pharmaceutical supply chain was safe but it still needed constant monitoring. However, he was critical of online pharmacies and warned of poor understanding amongst patients about how to tell the difference between a legitimate and illegal online pharmacy.
The numbers here are staggering. The Falsified Medicines Directive was brought in to increase the safety of medicines in Europe. Whilst the academics say that there still needs to be better understanding in the developed world, the problems are far worse in the developing world. People making money by supplying fake drugs are doing so at the expense of hundreds of thousands of people's lives each year. The pharma industry, governments and others need to come together to do more to improve the situation.