Every question you have about weight-loss injections, answered.

The public debate around weight-loss drugs has never been louder than it is right now.

Initially created to help control blood sugar levels in patients such as those with type 2 diabetes, the rise of 'off-label' usage – such as those who use the drugs for weight loss rather than their intended original purpose – is being blamed for a shortage in their availability.

The Therapeutic Goods Association (TGA) has advised that supply for the rest of 2023 and 2024 will be limited, stating that supplies should be conserved for patients with type 2 diabetes who are stabilised on the drug.

The topic has proven polarising: some have praised the injectable drugs, while others are warning against their use, and recent headlines have suggested they can even be deadly.

From supply to side effects, below are the answers to all the questions you might have about these weight-loss drugs amid their shortage.

Listen: Mamamia's daily news podcast The Quicky. Post continues below audio.

What does 'off-label' use mean?

Patients with type 2 diabetes may be prescribed these medications through the pharmaceutical benefits scheme (PBS), which means the government will provide a rebate. This drastically subsidises the cost of the prescriptions.

However, off-label usage refers to anyone being prescribed the medication for other reasons, including weight loss. These prescriptions are not covered by the PBS, and patients will foot the full cost.

"It's not got across the line in Australia as far as being used for that purpose, or economically viable for the country for that purpose," Dr McKay told The Quicky.

Who is being prioritised during this drug shortage?

The TGA is advising doctors not to initiate new patients onto these medications unless there are no suitable alternatives or a compelling medical reason to do so — meaning that type 2 diabetics will be prioritised over anyone requesting off-label usage.

"From a GP perspective like myself, we're told [to] try not to prescribe semaglutide [the active ingredient in these drugs] for new patients'. If everything else has failed and your patient has diabetes, then our hand is forced to give that medication that could keep someone alive," he said.

"But if you're going into your GP for weight loss, they're not going to be prescribing that for you off-label at this time."

What is a compounding chemist?

Dr McKay said many pharmacists will only have a small shipment of medication, which they will allocate to patients that need it for their blood sugar levels.

With the shortage of these medicines, many people are being recommended a 'compounding chemist'. 

In Australia, a compounding pharmacy is a pharmacy that is licensed and qualified to make medicine and other health care products, at their own local facility, using raw pharmaceutical ingredients.

Dr McKay said these pharmacies may pay top dollar to import the drugs into Australia, and then pass on that cost to consumers, and so far in Australia, the medications have been genuine.

"But there are some stories around the world where counterfeit supply has been coming in and a number of stories around the world where people have either bought the medication online or even bought the medication through another pharmacy and it hasn't been what's on the label," he said.

"This is where we are getting into really dangerous territory. If you're injecting yourself with a drug that isn't what's written on the packet, it can be a disaster – and has been a disaster for many people.

"So far in Australia, no counterfeits are being sold, [but] you've just got to be very careful online. I would be very prudent with your research if you were trying to do that."

What are the dangers of off-label usage?

Australians may have seen headlines around 56-year-old Trish Webster, who died of acute gastrointestinal illness in January. She had been taking weight loss medications in preparation for her daughter's wedding, and her husband told 60 Minutes she had returned to her GP a couple of times with stomach and gut issues.

Her death is not currently linked to the drugs she was taking.

Dr McKay said that, as with any medication, there are possible side effects to be aware of.

"Any of the drugs in this group can cause your gut to slow down. So one of the common side effects from using them is to get constipation," he told The Quicky.

"It can also cause lots of nausea and, in extreme cases, it has been known to cause what's known as an ileus. This is when the gut slows down so much, [and] you get so constipated, that it just stops. Then fluid builds up.

"It's a medical emergency when this does happen. Often people need to be in hospital and need to have fluids put through a drip, and stop the medication and get their bowel back to normal over time."

Is the TGA reconsidering weight-loss drug approvals in Australia?

On November 11, the TGA confirmed it was reviewing an application to recognise a drug that has the active ingredient tirzepatide as a weight-loss medication.

Currently, Dr McKay said this class of drugs is getting "tweaked" as time goes on.

"These drugs are, overall, well tolerated and can also be amazingly remarkable for keeping people's sugars under control."

As for the off-label side of things? "As we're looking more and more into the weight loss aspects of it, it also looks really favourable."

What should people worried about supply do in the face of this shortage?

For those who are taking these drugs for type 2 diabetes, these shortages can be really scary. There have been reports of people scouring pharmacies in search of the very limited supply.

Dr McKay said the best course of action is to speak to your GP, as there are likely changes that can be made to prescriptions to try to keep up with shortages.

For those who are using it off-label, the immediate health issues are not as dire.

"If you are just using the medication as weight loss – using it 'off-label' – then if you stop the medication, it's not going to be the end of the world," he said.

"You just need to be careful over time and then recommence it later on when stocks do become available."

Feature image: Getty.