Mirtazapine Therapy
A 44-year-old woman with a history of major depression and obsessive-compulsive disorder was prescribed mirtazapine. She came to the emergency department approximately 2 months after starting therapy; severe hypertriglyceridemia, acute pancreatitis, and diabetic ketoacidosis were diagnosed. Although these adverse effects have been reported in early clinical trials, we found only three published cases of subclinical pancreatitis possibly associated with mirtazapine therapy. We suspect that mirtazapine-associated hypertriglyceridemia had contributed to the development of acute pancreatitis and diabetic ketoacidosis in our patient. All these problems resolved with supportive care and discontinuation of mirtazapine. Her serum amylase, lipase, and lipid levels were normal 2 months after the acute event occurred. Health care providers should be aware of these possible adverse effects. Serum glucose and triglyceride levels should be measured at baseline and monitored regularly thereafter in all patients receiving mirtazapine therapy.

Mirtazapine is an antidepressant with a tetracyclic structure unrelated to the selective serotonin reuptake inhibitors, tricyclics, or monoamine oxidase inhibitors. Common adverse effects with mirtazapine reported in early clinical trials were somnolence (54%), dizziness (7%), increased appetite (17%), weight gain (8%), increased nonfasting serum cholesterol (15%) and triglyceride (6%) levels, elevated liver function (2%), constipation (13%), and dry mouth (25%). Other less commonly reported adverse effects (< 1%) were activation of mania or hypomania, asthenia, agranulocytosis, and neutropenia. Although both acute pancreatitis and new-onset diabetes mellitus possibly associated with mirtazapine therapy were reported in clinical trials, our literature search yielded only three cases of possible mirtazapine-induced pancreatitis without concurrent complications from diabetes.

We describe a patient who developed acute pancreatitis, new-onset diabetes mellitus, and markedly elevated serum cholesterol and triglyceride levels approximately 2 months after staring mirtazapine therapy.