A global taskforce to fight drug counterfeiting needs to be set up, the World Health Organization has said.
Fake lifestyle drugs are frequently for sale in European countries
Fake drugs are thought to account for one in 10 drugs sold worldwide, and medicines counterfeiting is a growing and lucrative business, it says.
It urged customs, police and drug enforcements agencies to shut down the sophisticated production networks.
The call comes as a meeting of regulatory, pharmaceutical and consumer representatives takes place in Rome.
Howard Zucker, the assistant director-general for the WHO for health technology and pharmaceuticals, said fake drugs could be deadly.
He said: "People don't die from carrying a fake handbag or wearing a fake t-shirt. They can die from taking a counterfeit medicine."
The WHO suggests that bar-coding medicines, increasing surveillance methods and improving both patient and healthcare worker education could help ensure fewer people take fake drugs.
The United Nations health agency also wants those charged with tracking down the culprits to work together and share more information.
Drugs counterfeiting is most common in developing countries where life-saving drugs can be sold on the streets.
But there are a growing number of cases of fake medicines being discovered in Europe - although these tend to be lifestyle drugs.
A spokeswoman for the WHO medicines and health technology department fake Tami-flu had been found in the Netherlands and Spain.
"The counterfeiters are getting more sophisticated and fake drugs are now even entering the official distribution systems," she warned.
She said there was also a need for a universal approach as in some countries drug counterfeiting was not even considered a crime or was thought of as an offence that was not very serious.
"But this is a crime that can kill people," she said.
A spokeswoman for the Medicines and Healthcare Products Regulatory Agency said there had been four cases of fake drugs being discovered in Britain the past 10 years. The last one was in July, she said.
"There are nearly 650 million prescriptions issued in the UK every year so four cases in the last 10 years is minimal.
"But we recognise that there's an increasing problem, and have our own anti-counterfeiting strategy."
The agency also assists eastern European countries in their fight against drugs counterfeiting.
The spokeswoman added that a suspicious batch of anti-flu drug Tamiflu seized in the UK last month by the agency had turned out to be illegally imported rather than counterfeited.