By Tom Miles

GENEVA (Reuters) - More than 20,000 deaths might be prevented every year in the United States alone if naloxone, used to counter drug overdoses, was more widely available, the World Health Organization said on Tuesday.

Few countries have such good data as the United States, but the WHO estimates about 69,000 people around the world die each year from overdoses of heroin or other opioids, with Iran, Russia and China known to have high numbers of opioid users.

Naloxone, a generic drug, is used to counter overdoses of heroin and prescription opioids including hydrocodone, oxycodone, codeine and tramadol.

Opioids are prescribed for chronic non-cancer pain such as lower back pain, but they are the most addictive substances in common use and the most commonly prescribed drugs in the United States, said WHO expert Nicolas Clark.

The United States has seen a tenfold increase in prescription opioid use in a decade, and they caused more than 16,500 deaths in 2010, while heroin deaths numbered about 4,000.

Most people overdose because they misjudge the dose or their own tolerance for the opioid and their death is often witnessed by a family member who would be on hand to administer naloxone, Clark said.

"If opioids are easily available in people's bathroom cabinets, it might make sense for naloxone to be equally available," Clark said.

Previously its use was limited by the need to inject it, but recent advances had shown it was effective as a nasal spray and it could work within 2-3 minutes, with no side effects.

"We're happy to recommend the intranasal approach as an effective approach," Clark said. "Naloxone is cheap but it's limited really to emergency departments and some ambulance departments."

Addiction experts writing in the British Medical Journal welcomed the new guidance, saying it would help save more lives among heroin addicts.

Last month, Scotland, the first to introduce a national program to provide naloxone, released results showing a marked reduction in opioid overdose deaths among people just released from prison, a particularly high risk group, from 9.8 percent in 2006 and 2010 to 4.7 percent in 2013.

Schemes to make naloxone available are being implemented around the world after Scotland's national take-home naloxone program began in 2011, with Wales's scheme starting the same year. City and state schemes have recently started in parts of the United States, Europe and Australia.


(Reporting by Tom Miles; additional reporting by Kate Kelland; Editing by Janet Lawrence)