A long-anticipated loosening of the availability of medicinal cannabis is expected to offer new treatments and choice for a range of patients.

New South Wales doctors can legally prescribe medicinal cannabis for their patients from Monday when new regulations come into effect.

Under the amendments to the Poisons and Therapeutic Goods regulations, cannabis-based medications will be available to a range of people for whom more mainstream treatments are not effective.

Cannabis-based medicines were previously only available to patients enrolled in clinical trials in NSW, but Premier Mike Baird said under the regulatory changes the drugs could be prescribed for patients who have exhausted standard treatment options.

“People who are seriously ill should be able to access these medicines if they are the most appropriate next step in their treatment,” Mr Baird said on Sunday.

The Poisons and Therapeutic Goods Amendment Regulation will allow doctors to apply to the NSW Health Board to prescribe cannabis-based products that are not currently on the Australian Register of Therapeutic Goods.

See the conditions and uses for medicinal cannabis below:

Source: Medicinal Cannabis in Australia: Science, Regulation & Industry

Among the potential uses for medical cannabis is the treatment of arthritis, epilepsy, glaucoma, schizophrenia, Crohn’s disease and sleep disorders.

“This change increases the options available for doctors as it means a broader range of cannabis-based medicines can be prescribed – while we continue our evidence-based research looking further into the role medicinal cannabis can play,” Mr Baird said.

Medicinal cannabis can be taken orally, smoked, used as an oil and in some cases injected.

Medicinal cannabis is legal in 20 US states. Photo: Getty

Medical cannabis is legal in 20 US states, while recreational cannabis can be sold legally in Colorado and Washington states.

Medical Research Minister Pru Goward was quoted by News Ltd as saying NSW was regulating cannabis-based medicines in the same manner as any other emerging medicine.

“Patients wishing to investigate the use of cannabis-based medicines will need to talk with their doctor about suitability,” Ms Goward said.

“There is still a lot to learn about safety and efficacy for different patient conditions and groups, which is why we are investing $21 million to further world-leading … research.”

Australian Medical Association NSW spokesman Associate Professor Saxon Smith told News Ltd that doctors will need approval from both the Commonwealth Therapeutic Goods Administration and NSW Health before they can prescribe an unregistered cannabis-based product.

“It is an important step forward to look after patients in terminal situations or suffering side effects from chemotherapy, so it adds to our arsenal,” he said. “This isn’t wholesale access to any type of cannabis. It’s about medication obtained legally and it doesn’t mean homemade tinctures and oils.”

A commercial cannabis farm operated by Canadian licensed supplier Tweed. Source: Tweed

Anecdotal reports say that in the absence of legal cannabis-based medicine, many patients have been forced to break the law by sourcing cannabis oil and medicine on the black market.

Last week, the NSW government gained approval to grow cannabis under licence from the federal government as part of research into the best way to cultivate the plant.

“This underpins the potential pharmaceutical supply of cannabis-based medicines made in Australia,” NSW Primary Industries Minister Niall Blair was quoted as saying by Fairfax. “We are the first state to be authorised by the Commonwealth to conduct cultivation research.”

The drug will be grown at a high-security facility under strict protocols.