A leading endocrinologist says patients with type 2 diabetes may have to revert to older treatments as a global shortage of dulaglutide begins to bite following a sharp rise in demand.

Last week, the TGA warned there would not be enough of the GLP-1 receptor agonist to fill all scripts until at least early 2023 and urged affected patients to be reassessed by a doctor as soon as possible.

The regulator said the dulaglutide (Trulicity) shortage was dependent on the availability of semaglutide (Ozempic), which has also been in short supply because of a surge in off-label use for obesity management.

Associate Professor Neale Cohen, head of diabetes clinical research at the Baker Heart and Diabetes Institute in Melbourne, said the limited supply was having an impact on patient care.