Health officials have issued an alert over a number of illicit drugs that can increase suicidal thoughts and have potentially fatal consequences, especially when taken in conjunction with alcohol and certain painkillers.

Public Health England (PHE) said the bootlegged sedatives were being marketed as legitimate anti-anxiety medications commonly prescribed by doctors on the NHS.

It said evidence linked to toxicology results from recent hospital admissions and deaths, as well as from seized caches of the tablets, shows that the counterfeit drugs were causing harm.

Drug research charity Release said it is still unclear where the illegal drugs are coming from, but that many are being supplied to dealers via the dark web. It found that users are still primarily relying on face-to-face transactions to obtain the drugs and that some of the surge was being driven by people who are normally dependent on heroin.

PHE advised users to watch out for a tablet with ‘DAN 5620′ on one side and ’10’ on the other, as well as one marked ‘T-20’, ‘TEM 20’, ‘Bensedin’ and ‘MSJ’.

It said most of the dangerous tablets, sometimes referred to as ‘street benzos’, are blue but may come in other colours and may stain people’s mouths.

Often they have been packaged in blister packs or proper pharmacy tubs to make them appear legitimate, and may claim to contain a certain dose of approved drugs, such as diazepam.

In reality, they may not contain any genuine medicines and will instead have high-potency illicit benzodiazepines or another non-medical substance.

The strength of street benzos can vary widely, putting the user at risk of overdose as they have no reliable measure of their intake.

Benzodiazepines impact brain activity and slow the central nervous system, which affects breathing. They are even more dangerous when used with other substances that have the same effect, such as heroin and other opioids, as well as epilepsy medication and painkiller gabapentinoids.

Release’s executive director, Niamh Eastwood, said many herion users lost their income during lockdown and have turned to cheaper alternatives.

‘One of the drivers of the increase, in the early part of lockdown was that heroin users lost income and couldn’t buy it so shifted to benzos which are significantly cheaper,’ she said.

This was exacerbated by the bust of the ‘EncroChat’ crime network, which saw over 700 arrests and had also significantly disrupted the heroin market, causing many to switch to benzos.

Director of charity DrugWise, arry Shapiro, said the distribution of the drugs in industry-standard packaging allowed some dealers to convince buyers they were genuine medicines that had found their way onto the black market.

‘If you make something look legitimate people then either believe that it is or con themselves into believing that it is until they find out otherwise,’ he said.

PHE warned the drugs also impact mental health and can increase suicidal thoughts, particularly in young adults and people with alcohol or opioid addiction.