Background: The novel antidepressant mirtazapine has been linked to elevated random plasma total cholesterol (TC) levels. The purpose of this study was to evaluate in a more controlled and precise approach the putative effects of mirtazapine on plasma lipids.
Method: In a double-blind design, 50 healthy subjects (30 women and 20 men) were randomized to receive either mirtazapine (N = 28) or placebo (N = 22) for a 4-week period. The study was conducted from June 1997 to September 1998. The initial dose for the mirtazapine group was 15 mg daily, which was increased to 30 mg daily at the beginning of the second week. Body weight and plasma lipoprotein profiles, including TC, low-density lipoproteins (LDL), high-density lipoproteins (HDL), and triglycerides, were determined at baseline and at weekly intervals throughout the study period.
Results: At baseline, there were no group differences in any of the measures. There was a statistically significant increase of 2.5% in mean body weight over the course of the study in the mirtazapine group that appeared to reach a plateau at 3 weeks, while no increase was observed in the placebo group. Mirtazapine subjects also showed significantly increased TC at week 4 (p =.016) and a transient rise in triglycerides that normalized by week 4. No significant changes in any of the other lipid parameters, including HDL, LDL, and TC/HDL ratios, were observed within either group. Changes in TC were significantly and positively correlated with changes in weight (p <.01).
Conclusion: These results suggest that while mirtazapine may be associated with increased TC, it does not increase LDL levels or affect the ratio of TC to HDL.