The two drugs have been touted as potential treatments for COVID-19, but months of testing is needed.

Pharmacists are being ordered not to dispense two drugs touted as a potential "cures" for coronavirus.

Key points: There has been a major rush for the drugs hydroxychloroquine and chloroquine, triggering a shortage

Early tests of the drugs have shown "positive signals" in the fight against COVID-19, but scientists say their effect remains unproven

Pharmacists have warned of a disturbing trend of doctors, nurses and dentists prescribing to friends, family and the community

The directive came after Australian pharmacies saw a rush of people presenting scripts for the drugs hydroxychloroquine — sold as Plaquenil — and chloroquine from their GPs, or asking to buy it over the counter.

Demand skyrocketed following a press conference by US President Donald Trump last week, in which he touted the drugs as a "game changer" — comments based on a World Health Organisation report labelling the drugs a "potentially useful" preventative and curative treatment for COVID-19.

Pharmaceutical Society of Australia president Chris Freeman said Australian pharmacies had seen unprecedented demand for the medications, creating a shortage for patients who actually needed them.

He said while there were "positive signals" from the drugs in the fight against coronavirus he called on people not to "buy into the hype".

"I think the worst thing that could happen is people start using these medicines in the hope it will prevent the virus, and then relax on other measures to prevent [it]," he said.

Both drugs are used to treat rheumatoid arthritis — a disease where patients can spend years trialling drugs until they find one that is right for them.

If too much pressure is put on supplies, potential shortages will mean patients who miss out on their regular drugs may experience painful flare-ups, experts say.

Dr Freeman has asked pharmacists to keep their supplies of hydroxychloroquine safe, and pharmacists have written to the Australian Medical Association (AMA) and Royal Australian College of GPs (RACGP) to ask their members to stop prescribing it.

The Australian Medical Association backed the pharmacists' call.

AMA committee member Chris Moy told the ABC the drugs were not widely used in Australia and warned regulation may be needed to limit their supply to the patients who actually needed them.

"There's only some limited evidence of (COVID-19) benefits, in conjunction with other drugs," Dr Moy said.

So, do they work?

In laboratory tests chloroquine has been found to be effective against some viruses such as chikungunya, dengue, and influenza.

But the WHO report, released earlier this month, said in studies with animals and in randomised controlled trials with humans the medication had been largely disappointing against COVID-19.

Medical experts say the advantage of chloroquine — approved for inflammatory conditions and the suppression and treatment of malaria — is that it is relatively safe, has few side effects and is cheap to produce.

David Paterson, from the University of Queensland, said chloroquine, along with an older HIV medication, had been found to kill coronavirus in laboratory tests.

"There's certainly positive signals either this [HIV drug] or this anti-malaria drug actually work really well against COVID-19," Professor Paterson said.

"We know that in the test tube and in the patients they have studied so far they've been able to recover and there's no more evidence of virus in [their] system."

His team at the Centre for Clinical Research hopes to start human trials in as little as three months.

Clinical trials in patients are also underway in China, the US, UK and Spain.

Scientists are also investigating whether hydroxychloroquine and chloroquine might be useful as a preventative treatment.

Up to 20,000 international healthcare workers will be recruited and given a small daily dose of chloroquine for three months.

Dodgy prescriptions

Dr Freeman said the rush for hydroxychloroquine and chloroquine, and the number of prescriptions in the system, were part of a disturbing trend.

"Unfortunately we're seeing some pretty non-evidence based practice at the moment," he said.

"We're seeing doctors prescribing for other doctors and their families. We're even seeing dentists prescribing to the community outside the context of dental work.

"We're seeing other non-medical prescribers like nurse practitioners starting to prescribe some of these things."

Dr Freeman is calling on pharmacists to only dispense the drugs to patients they know require them.

"If a patient has been coming into the pharmacy for quite a while and has been using those medicines in the past, then they are able to get a supply of that medicine," he said.

"We're calling all prescribers to stop prescribing these in the short term until we have some more evidence on whether these medicines are effective in these conditions and are safe to do so.

"We need to go back to what we were doing previously and make sure clinical trials are conducted to make sure these things are effective before we start using them."