A new medication has become available in Australia to help people with obesity lose weight, bringing the total number of drugs available from three to four.
Australians struggling with obesity have a new drug available to them to treat the condition, following its approval for use.
The listing of the weight loss medication on the Australian Register of Therapeutic Goods is a "rare" step that will help more people access treatment that works for them, according to a leading obesity researcher.
Contrave, which is intended to be used alongside a reduced calorie diet and increased exercise, combines two drugs already used in Australia, often to help people shake dependence on smoking and alcohol.
The pill affects the central nervous system, by both suppressing appetite and reducing food cravings.
It has been shown in clinical trials to help people lose on average five per cent of their body weight.
That may not sound like a lot, but it is enough to improve people's metabolic health and reduce rates of cardiovascular disease, diabetes and lipid disorders, according to the drug's Australian inventor.
Researcher Michael Cowley - now Head of the Monash Biomedicine Discovery Institute's Department of Physiology - discovered the drug while he was working in the United States.
Professor Cowley says he hopes the extra medication on the market, which has been approved for use in the US since 2014, will help people realise there are effective medical treatments available.
That will also help break down inappropriate social stigma, he believes.
"There is a sector of the medical community and a sector of the Australian political community who regard obesity as a moral failing," he told AAP.
"Most of the rest of the world has acknowledged it as a disease and applies normally clinical judgement to treating diseases."
Head of Clinical Obesity Research at Melbourne's Baker Heart and Diabetes Institute, John Dixon, says Contrave's listing lifts the number of obesity drugs available in Australia from three to four.
That comes as almost a third (28 per cent) of Australian adults are obese, with Professor Dixon saying "hardly any of them" are receiving effective weight loss therapy.
Some medications work for some people and not others, so increasing the available choices is important, Prof Dixon said, particularly given changing lifestyle factors is only effective for one-in-20 people.
"For those who really need it, and that's a lot of them out there, we need to see doctors actually treating obesity actively, with medical treatments," Prof Dixon told AAP.
"We wouldn't treat heart disease or diabetes or cancer just with lifestyle interventions, and yet that's the prescription for managing weight."
Contrave is not listed on Pharmaceutical Benefits Scheme - meaning the federal government is not subsidising it - and will cost those who use it about $230 to $250 per month.
Prof Dixon said no medications to treat obesity are listed on the PBS, despite plenty being listed to treat complications for the condition such as diabetes, hypertension, some cancers and sleep apnea.
"It's abysmal. This is called obesity stigma blame," he said.
The drug's side effects - established in clinical trials - include headache, constipation, dizziness, vomiting and dry mouth.