Risk of Acute Pancreatitis Real With Methimazole To further investigate the risk in a large population of methimazole users and the other most commonly used antithyroid drug, propylthiouracil (PTU), Hegedus and colleagues identified 118, 649 antithyroid drug users (defined as having at least one prescription of either agent) in national registries in Denmark from 1995 to 2018, including 103, 825 methimazole users and 14, 824 PTU users.