The number drug overdose deaths in the U.S. has been rising steadily for well over a decade, with the Centers for Disease Control and Prevention announcing in 2010 that the figure had increased for an 11th consecutive year, hitting 38,329. By 2013, this had leapt to 43,982. However, there is a little-known medication that actually reverses the effects of opioid overdoses, and efforts are now being made to increase its availability.

Opioids are substances that dull feelings of pain by binding to opiate receptors throughout the brain and body. They include a range of prescription painkillers as well as illegal drugs such as heroin. Their effects can be cancelled out by a substance called naloxone, which is a competitive opioid antagonist. This means that it binds to opiate receptors without activating them, effectively blocking them and thereby reducing the effects of any opioid-containing drugs. However, it has to be administered pretty quickly, since death usually occurs less than three hours after overdose. For this reason, global laws regulating the use of naloxone are being revised in order to ensure that drug users have sufficient access to the medication.

For instance, in the U.K., a new law came into effect on October 1st allowing anyone working in a drug treatment service to administer naloxone without a prescription. In Australia, meanwhile, an interim ruling was passed last month downgrading naloxone from a Schedule 4 substance – referring to prescription-only medications – to Schedule 3, which would allow all pharmacists to supply it over the counter.

However, a spokesperson for Public Health England told IFLScience that, as long as naxolone remains an injectable, it is unlikely to become an over-the-counter treatment in the U.K. In order to overcome this obstacle, several companies around the world are now developing naloxone nasal sprays and sublingual (under the tongue) sprays. The U.S. Food and Drug Administration (FDA) has even fast-tracked the development of one particular sub-lingual version of the substance.

The potential of naloxone to reduce opioid overdose deaths has been highlighted in a number of studies, one of which indicated how administration of the medication by bystanders significantly increased the odds of recovery after overdose. This lends weight to the argument that all drug users and their relatives should have ready access to naloxone, so that it can be applied as quickly as possible during an emergency.

While opiates are not responsible for all drug overdoses, they are involved in a large number of cases. For instance, in 2013, more than 16,000 deaths in the U.S. were caused by prescription opioids, while a further 8,000 resulted from heroin overdoses.