Publications

Glucagon-like peptide-1 receptor agonists: stay hydrated

Published: 5 June 2025
Prescriber Update 46(2): 24–25
June 2025

Glucagon-like peptide-1 (GLP-1) receptor agonists are indicated for type 2 diabetes mellitus and weight management.
Vomiting and diarrhoea are common adverse reactions associated with GLP-1 receptor agonists, which can lead to dehydration and renal impairment.

Glucagon-like peptide-1 (GLP-1) receptor agonists are indicated for type 2 diabetes mellitus and weight management. ^1-5 These medicines mimic the hormone GLP-1,^1-5 and increase insulin secretion, suppress glucagon secretion and slow gastric emptying.¹ For the treatment of type 2 diabetes mellitus, GLP-1 receptor agonists may be used as monotherapy or in combination with other diabetes medicines.¹

The GLP-1 receptor agonists currently approved in New Zealand are:

dulaglutide (Trulicity)
liraglutide (Saxenda, Victoza)
semaglutide (Ozempic, Wegovy).

Gastrointestinal side effects are common

Gastrointestinal disorders are common, and usually non-serious, adverse reactions associated with GLP-1 receptor agonists.^1-5 However, nausea, vomiting and diarrhoea, especially at the initiation of treatment, can persist for several days. If the patient becomes dehydrated, they are at risk of an acute renal injury or worsening of chronic renal failure.^1,6

Advise patients to stay well hydrated by drinking plenty of fluids (eg, water) and inform them of the potential risks associated with dehydration.^1,6 Also advise patients to seek medical attention if gastrointestinal symptoms are severe or persistent.⁷

Prescribers should consider delaying dose escalation or reducing to a lower maintenance dose if significant gastrointestinal symptoms occur in patients.⁵Also consider delaying administration if acute gastrointestinal illness is present on the day that the dose is due. Advise patients to follow their ‘sick day management plan’.^8,9

The data sheets contain information about dehydration and renal impairment.

New Zealand case reports

Between May 2007 (when the first GLP-1 receptor agonist was approved in New Zealand) and 31 March 2025, there were 111 case reports where a GLP-1 receptor agonist was reported to be the suspect medicine. Of these 111 reports, 63 were for dulaglutide, 38 for liraglutide, 5 for semaglutide (not currently marketed) and 5 for exenatide (approval lapsed).

The most frequently reported reactions were nausea (29 reports), vomiting (24) and diarrhoea (20).

There were 11 reports of renal adverse drug reactions, 7 of which were for dulaglutide, 3 for liraglutide and 1 for exenatide.

Additional information

See the specific GLP-1 receptor agonist data sheets for more information.

References

Eli Lilly and Company (NZ) Limited. 2021. Trulicity New Zealand Data Sheet 29 January 2025. URL: www.medsafe.govt.nz/profs/Datasheet/t/trulicityinj.pdf (accessed 17 April 2025).
Novo Nordisk Pharmaceuticals. 2023. Ozempic New Zealand Data Sheet 15 November 2024. URL: www.medsafe.govt.nz/profs/Datasheet/o/Ozempicinj.pdf (accessed 17 April 2025).
Novo Nordisk Pharmaceuticals. 2016. Saxenda New Zealand Data Sheet 27 January 2025. URL: www.medsafe.govt.nz/profs/Datasheet/s/saxendainj.pdf (accessed 17 April 2025).
Novo Nordisk Pharmaceuticals. 2010. Victoza New Zealand Data Sheet 27 January 2025. URL: www.medsafe.govt.nz/profs/Datasheet/v/Victozainj.pdf (accessed 17 April 2025).
Novo Nordisk Pharmaceuticals. 2025. Wegovy New Zealand Data Sheet 20 March 2025. URL: www.medsafe.govt.nz/profs/Datasheet/w/wegovyinjection.pdf (accessed 17 April 2025).
Medicines and Healthcare products Regulatory Agency. 2024. GLP-1 receptor agonists: reminder of the potential side effects and to be aware of the potential for misuse. MHRA Safety Update 18(3): 1. URL: www.gov.uk/drug-safety-update/glp-1-receptor-agonists-reminder-of-the-potential-side-effects-and-to-be-aware-of-the-potential-for-misuse (accessed 17 April 2025).
Eli Lilly and Company (NZ) Limited. 2024. Trulicity Consumer Medicine Information May 2024. URL: www.medsafe.govt.nz/Consumers/CMI/t/trulicity.pdf (accessed 24 April 2025).
New Zealand Formulary (NZF). 2025. NZF v155: Glucagon-like peptide 1 receptor agonists (diabetes mellitus) 1 May 2025. URL: nzf.org.nz/nzf_70808 (accessed 7 May 2025).
Healthify. 2022. Diabetes – type 2 sick day plan updated 25 September 2024. URL: healthify.nz/health-a-z/d/diabetes-type-2-sick-day-plan (accessed 7 May 2025).