Acute pancreatitis induced by methimazole in a patient with Graves' disease.

BACKGROUND

Antithyroid drugs such as methimazole (MMI), the mainstay of pharmacologic therapy for Graves' disease, can provoke a variety of adverse effects. MMI-induced acute pancreatitis is very rare, being described in only a few patients and never after more than two exposures as reported here. Here, we report an 18-year-old girl with Graves' disease who developed acute pancreatitis each time she received MMI.

SUMMARY: The patient was an 18-year-old girl with Graves' disease who took MMI on four occasions. Each time she promptly developed similar features consisting of high fever and left upper quadrant abdominal pain. On three occasions, serum lipase and amylase values were measured. Serum lipase was elevated on all three occasions and serum amylase was elevated once. Features resolved after MMI was stopped. We considered these episodes to be most consistent with pancreatitis, and to be induced by MMI administration.

CONCLUSION

MMI-induced acute pancreatitis is rare and easily misdiagnosed. Based on very limited experience, it should resolve after MMI is stopped. The pathogenesis of MMI-induced pancreatitis is not known. Clinicians should be aware of this entity so that MMI is promptly stopped if the features described here develop after MMI is started, and measures are taken to avoid future MMI treatment.