Perth's black market in prescription drugs is booming and health professionals say they cannot control it.

With a single tablet of the powerful painkiller oxycodone selling on the street for $50, trade is thriving and doctors and pharmacists say they do not have the powers or the tools they need to identify dealers and addicts.

"Every doctor and every pharmacy in this State has stand-alone computers, but these computers don't talk to each other so there is no simple centralised record of who is getting what," Lenette Mullen, of the Pharmacy Guild of WA, said.

Without that information there is no way to stop doctor-shopping - where people visit a string of GPs and collect numerous prescriptions for powerful drugs.

Addiction specialist Dr George O'Neil says he is seeing more and more people addicted to prescription drugs.

"Prescription drug addicts use doctors and pharmacists in the same way as heroin addicts use street dealers," he said.

Figures from the Pharmaceutical Benefits Scheme show nearly 134,000 scripts for oxycodone were dispensed in WA last year costing taxpayers $5.78 million.

No-one can say how many of these scripts ended up on the black market.

"Addicts get the same high from many prescription drugs as you get from heroin and we all know that doctors and pharmacists don't share their records - so doctor-shopping is a low-risk way of getting safe drugs," former drug addict and "doctor-shopper" Mike Desbouvrie said.

Pseudoephedrine is the only dangerous drug which is tracked in real time. It is found in cold and flu tablets and can be turned into methamphetamine.

Pharmacists are required to ask for photo identification from anyone buying pseudoephedrine and those details are kept on a computer record which all pharmacists can access.

The customer's details remain on file for several days and during that time that person will not be sold pseudoephedrine by any pharmacist.

"It's a simple system but it works very well," Ms Mullen said. "If that system was widened to include the prescription drugs which are targeted by addicts and dealers, that would go a long way towards stamping out people's ability to abuse the system."

Medicare receives a copy of all prescriptions dispensed by pharmacies and carries out checks. Seven WA doctors are under investigation for overprescribing narcotic painkillers.
"Pharmacists need a database where they can see instantly if someone is getting drugs faster than they could ever use them," Bassendean MP and anti-drugs campaigner Martin Whitely said. "Those people will be the dealers."