The International Narcotics Control Board (INCB) said detailed instructions for how to make designer drugs, which are slightly altered to bypass existing control systems, are often shared via the Internet.

The report said the problem was “escalating out of control” and “major efforts” were needed to counter it.

“Given the health risks posed by the abuse of designer drugs, we urge governments to adopt national control measures to prevent the manufacture, trafficking in and abuse of these substances,” Hamid Ghodse, the INCB’s president, said at a briefing in London as the board’s annual report was published.

To address the problem of designers quickly changing a single component of a drug to avoid bans, some governments have adopted measures to control entire groups of structurally related synthetic compounds, the INCB said, recommending that others follow suit.

The INCB’s report cited the designer drug 4-methyl-methcathinone, known as “mephedrone,” which it said is being abused in a growing number of countries and regions.

Designer drugs are often produced by slightly modifying the molecular structure of controlled drugs, making a new drug with similar effects which can elude national and international bans.

Mephedrone is available through the Internet and also through retail outlets known as “smart shops,” sometimes advertised as bath salt, plant food or research chemical to avoid detection and legal proceedings.

The drug has effects similar to cocaine, amphetamine and MDMA, or “ecstasy.” A number of reports of deaths from using it have been reported in recent years in Britain and Europe.

“Mephedrone has now become a problem drug of abuse in Europe, North America, Southeast Asia and in Australia and New Zealand,” the INCB report said.

It added that mephedrone was just “one example of a large number of designer drugs that are being abused.”

In Europe alone there are 15 other designer cathinones — the class of drugs that includes mephedrone — currently being monitored by the European Monitoring Center for Drugs and Drug Addiction, and in Japan 51 drugs have been recently placed under control.

The INCB called on governments to remain vigilant in monitoring trends in drug abuse and in identifying new drugs of abuse. “Bilateral and international cooperation is essential in sharing information on this cross-border phenomenon,” it said.