An emergency medicine perspective on weight-loss injections

While the benefits of GLP-1 medications are striking, emergency medicine doctors are seeing cases related to their use

They are some of the most talked-about medicines in a generation, and mostly for good reason. Let’s start with what these drugs actually do, because that tends to get lost somewhere between the headlines and the Instagram adverts.

GLP-1 receptor agonists imitate a hormone your gut releases after you eat. They nudge the pancreas to produce insulin when your blood sugar is high, they slow down how fast your stomach empties, and they turn down the appetite signals in your brain. Semaglutide and liraglutide act on one receptor; tirzepatide acts on two. They were designed for type 2 diabetes, and they remain among its most effective treatments. The surprise was the weight loss: Around 15 per cent of body weight with semaglutide (at a 2.4mg once weekly dose) over 68 weeks and about 21 per cent with the top dose of tirzepatide over 72 weeks. Nothing in the previous 50 years came close.

When you pool the big cardiovascular trials, you see around a tenth fewer heart failure admissions and roughly an eighth fewer deaths from any cause, with a similar reduction in cardiovascular death. The benefit holds up in people with obesity who do not have diabetes. In a country where about 1.2 million adults – a quarter of us – live with obesity that matters enormously. Prof Donal O’Shea, the HSE Clinical Lead for Obesity, has estimated that around 80,000 people here would be candidates for treatment if the State funded these drugs more broadly.

Liraglutide is currently the only weight-loss injection reimbursed here, and only through a managed access protocol for adults with a body mass index over 35 who also have prediabetes and high cardiovascular risk. Semaglutide is covered for diabetes under the Long-Term Illness scheme. Wegovy and Mounjaro, for weight, are private prescription only.

So most Irish people taking these drugs are paying for them out of pocket, and a worrying number are buying them somewhere that is not a pharmacy. The Health Products Regulatory Authority (HPRA) seized 1,582 illegal GLP-1 items in 2024. Last year, it seized 48,752, mostly ‘GLP-1 drops’ and microneedle patches. Neither of these is a real thing. When the HPRA tested a sample of the patches, there was no semaglutide in them at all.

So what do we actually see?

Here is an example of a female patient (41). She is three weeks into taking a GLP-1 medication and hasn’t been able to keep water down for a few days. At triage, she said she was not on any medications because she does not think of the GLP-1 injection as a medication. It arrived in a box. It is a vial rather than a pen, and she has been drawing it up in units, the way you would insulin, because that is what the syringe is marked in.

That is just one type of case. Symptoms can include nausea, vomiting, diarrhoea, tummy pain, and dehydration. The older woman who is dizzy because nobody adjusted her blood pressure tablets after she lost eight kilos. In August, RTÉ reported the HPRA has logged more than 1,500 reports of suspected side-effects from these drugs, overwhelmingly gastrointestinal, along with nine reports of deaths in people known to be taking them. The HPRA stressed that the reports don’t establish that the drugs caused the side-effects or deaths.

Looking overseas, a US study estimated that clinicians attributed about 24,500 emergency department (ED) visits to semaglutide across 2022 and 2023. That sounds enormous until you realise it worked out at fewer than four visits per thousand patients dispensed the drug in 2023. Roughly seven in 10 were gastrointestinal in nature, one in six was due to low blood sugar, and about one in 11 involved a medication error. Four-fifths happened in the second year alone, as use of the drug grew rapidly.

A small UK pilot study at an ED found that clinicians judged the drug responsible for the visit in 79 per cent of patients who reported taking a GLP-1.

Mistakes, not misuse

Another point is worth noting. When US poison centres reviewed six years of GLP-1 calls, about four in five were therapeutic errors, rather than someone intentionally misusing the drug. Someone draws up 10-times the dose because the vial is measured in units and the pen is not. Someone takes a weekly drug daily. Someone doubles up after missing a week. And counterfeit pens have turned up containing insulin instead. Regulators have confirmed falsified Ozempic and Saxenda pens, with some recipients hospitalised in hypoglycaemic shock. Which is why “are you on a weight-loss injection?” is not enough of a question any more for ED healthcare staff. We need to know what it is, where it came from, what dose, and how it was measured. And the low blood sugars, for what it is worth, are almost never the GLP-1 acting alone. It is usually a GLP-1 on top of insulin or a sulfonylurea that nobody thought to reduce.

We need to know what it is, where it came from, what dose, and how it was measured

The things worth worrying over

Pancreatitis is the issue everyone asks about. An early study suggested a striking increase; a later one that accounted for a person’s starting weight did not make the same finding, though it did confirm a link with gastroparesis and gallstones.

The UK regulator has captured nearly 1,300 reports, 19 of them fatal, set against some 25 million packs dispensed over five years. It has started a genetic study to work out why a small minority of people seem particularly vulnerable.

The European Medicines Agency has also flagged a very rare form of sudden optic nerve damage with semaglutide. These risks are genuinely small – but small across millions of people still adds up.

The other issue is in relation to the stomach itself. Slow emptying is not a side-effect of these drugs; it is how they work. Patients who have fasted properly before a procedure are still turning up with food in the stomach – in one study, 56 per cent of users versus 19 per cent of non-users. Actual choking events remain rare and the advice has shifted from stopping the drug beforehand to assessing each person individually, with an ultrasound of the stomach if there is any doubt.

Ultimately these drugs work, and they prevent serious illness. The people they keep out of hospital do not show up in our figures. What we are currently seeing is mostly sickness, vomiting, and dehydration, and the numbers are increasing as more people start these medications.

Because almost nothing is reimbursed here for weight loss, people are buying online. For patients attending the ED, it is important that they tell the doctor they are taking these products, especially before any procedure. It counts as a medication, even if it did not come from a pharmacy.

Mater Private Network Cork’s walk-in ED service is open Monday to Friday, 8am to 6pm. For GP referrals or information, the team can be contacted on 021 601 3333 or email mpced@materprivate.ie

References available on request