Drug users have been urged to be extra careful following a high number of likely heroin overdoses.

Public Health England (PHE) has issued a warning of a sharp rise in the number of overdoses linked to people using drugs in several areas across England.

The national health authority said there are signs that the overdoses may be caused by heroin mixed with a potent and dangerous synthetic opioid, but further work is needed to confirm any links between the cases.

To date, there have been at least 46 poisonings resulting in 16 deaths but investigations are still ongoing. The areas affected include South London, the South East, South West and East of England.

‘We are urging drug users to be extra careful following reports of a sharp rise in the number of overdoses potentially connected to heroin, tragically with some deaths. We are urgently investigating with the police and local partners,’ said Rosanna O’ Connor, director of Drugs, Alcohol, Tobacco and Justice at PHE.

‘We strongly advise anyone using drugs not to use alone and to test a small amount first.

‘People need to look out for each other and be alert to any signs of an opioid overdose, such as shallow breathing, loss of consciousness and blue lips or fingertips.

‘If someone does overdose it’s vital to act fast, call for an ambulance immediately and if possible use the opioid antidote, naloxone, which can save lives.

‘We strongly advise all drug users to get support from local drug services, as being in treatment greatly reduces the risks of harm and overdose.’