A black market in prescription and over-the-counter drugs – from methadone to cough syrup – is thriving behind a “cloak of anonymity” in Bradford, police warn.

Prescription drugs are bought on the internet, obtained falsely from GPs or passed on by addicts taking prescribed medication in recovery. One former addict told the Telegraph & Argus that methadone is even regurgitated and passed on to other people.

Among the most commonly used, and dangerous, drugs are diazepam, tramadol, benzodiazepine, known as ‘benzos’, and some anti-depressants.

And a Bradford pharmacist highlighted the dangers of some over-the-counter medication, such as painkillers, antihistamines and sleep aids, which can become addictive.

According to a police statement at a recent inquest into the deaths of two women who died from taking drugs not prescribed to them, the sale, swapping or handing out of such drugs is “rife”.

The women were found on the same day, half a mile from each other on Lower Grange estate, Allerton. Detective Sergeant Steve Wedge told the hearing that selling and swapping prescribed drugs is a normal part of everyday life in some parts of Bradford.

Dr Alun George, Clinical Lead at Unity Recovery Centre, part of Bradford drug treatment charity Bridge, said the rise in use of prescription drugs is largely because they are accessible online.

Unity’s recovery-based treatment, which involves prescribing and reducing substitute medication, is mostly for users of Class A drugs, but Dr George also sees people dependent on prescription drugs. He said pressures facing GPs leave them with little time to spend with patients, and many repeat prescriptions slip “under the radar”.

“We talk to GPs about prescription drug problems and some react immediately, some are slower,” he said. “They have a difficult job, under a lot of pressure. And drug companies are constantly trying to get doctors to prescribe their drugs.”

A spokesman for West Yorkshire Police said that because not every incident or death related to prescription drug use is labelled as such, since other factors are often involved too, there are no specific statistics for the scale of the problem.

And Bradford Coroner’s Court was unable to reveal figures for inquests into deaths caused specifically by prescription drugs.

But Bryan Dent, West Yorkshire police force drugs co-ordinator, said police were “very aware” of the scale of the problem, which he said reflected a national trend.

He said prescription drugs are often taken both as substitutes for and enhancements to Class A and B drugs.

“We’re alive to the national picture of prescription drug misuse, and the black market. Unfortunately, it is not until there is a fatal consequence that it comes to general notice,” said Mr Dent. “National statistics show an increase in the use of drugs such as tramadol and pregabalin. The internet plays an integral part, and when drugs are sold on, it’s often the case that people take them unaware that they’ve been mixed with other substances.”

He said the internet has exacerbated the problem of synthetic substances, containing potentially lethal combinations of ingredients.

“When you obtain drugs from the internet you have no knowledge of how strong or how impure it is, and there’s no recourse,” said Mr Dent. “Some drugs out there contain a mix of substances. You don’t always know what you’re taking.”

He said the misuse is difficult to police.

“It’s a grey area,” said Mr Dent. “A fair percentage of people get medication from friends, who have often obtained it from their GP. It tends to be obtained this way, rather than by using dealers, so it becomes difficult to police. A lot of the handing out takes place in a domestic setting, or with friends. It’s hidden behind a cloak of anonymity “Sometimes it’s a case of taking the remainder of a course of medication prescribed to a family member or partner.”

He added: “Unless medication has been prescribed to you, it carries a risk. GPs make assessments of individuals before administering prescriptions. People don’t realise how dangerous these drugs can be, in the wrong hands, and how quickly they can become addicted to them.

“Because they’re prescription drugs, some people regard them as not “dirty” like heroin, for example. But people may have underlying health issues that mean they shouldn’t be taking certain types of medication. There’s also the issue of mixing drugs, and mixing drugs with alcohol, both of which are potentially fatal combinations.”