Does mirtazapine interfere with naturalistic diabetes treatment?

Mirtazapine is known to induce weight gain and possibly leads to exacerbation of diabetic profiles. However, many cases of diabetic patients, who complained of insomnia and depression, were treated with mirtazapine in the clinical situations. Thus, this study aimed to assess any negative effects that treatment with mirtazapine may incur in diabetic patients.This study included 33 patients enrolled in naturalistic diabetes treatment that had also been diagnosed with depression and prescribed mirtazapine for at least 6 months. Another 33 diabetic patients who had not taken any psychiatric medicines were included as a control group. Body mass index, fasting plasma glucose, HbA1c, total cholesterol, triglyceride levels, high-density lipoprotein, and low-density lipoprotein were assessed at baseline, 3 months, and 6 months.The dose of mirtazapine at baseline was 24.3 ± 14.0 mg/d in the mirtazapine group, and the 2 groups did not differ in any baseline characteristics except for total cholesterol levels. Body mass index increased in both groups, and the change in the mirtazapine group (1.0 ± 0.6 kg/m) was significantly greater than that in the control group (0.3 ± 0.4 kg/m, P < 0.001) at 6 months. Only the control group exhibited a decrease in fasting plasma glucose, whereas both groups showed a decrease in HbA1c, low-density lipoprotein, and total cholesterol, an increase in high-density lipoprotein, and no change in triglyceride levels. None of the differences between the groups were statistically significant.In conclusion, mirtazapine increased the weight gain of diabetic patients; however, other diabetic and lipid markers generally did not worsen during the 6-month treatment period. These results suggest that, at least in the short term, mirtazapine is safe for diabetic patients in a stable state and are undergoing appropriate diabetic treatment.