New figures show the State has spent almost 2.63 million euro on the diabetes drug Ozempic across the Shannonside region from January to August this year.
The highest costs were in Longford and Westmeath at almost 1.4 million euro combined.
Roscommon recorded spending of just under 548 thousand euro, with Sligo and Leitrim at just over 685 thousand euro.
Nationally, the figure stands at close to 40 million euro.
These figures cover prescriptions for patients with long-term illness and general medical services.