Lipid lowering efficacy between morning and evening simvastatin treatment: a randomized double-blind study.

OBJECTIVES To compare lipid-lowering efficacy and high sensitive C-reactive protein (hsCRP) level between morning and evening simvastatin administration in hyperlipidemia subjects. MATERIAL AND METHOD A randomized double blind controlled trial was conducted in 52 dyslipidemia subjects. A group of twenty five subjects received 10 mg simvastatin in the morning and placebo in the evening. The other group of twenty seven subjects received vice versa. Serum lipid profiles were evaluated every 4 weeks for the total course of 12 weeks. High sensitive CRP was measured at the beginning and the end of the study. RESULTS Baseline LDL levels were similar in both groups (p = 0.95). The evening simvastatin group had significantly less low density lipoprotein level (LDL) than the morning group at 4 weeks (112 +/- 26.1 mg/dl vs. 136.3 +/- 32 mg/dl, p = 0.001) and 8 weeks after treatment (109.7 +/- 28 mg/dl vs. 129.5 +/- 27 mg/dl, p = 0.006). Difference in LDL after 12th week between two groups was not significant (p = 0.23). Triglyceride and HDL level were not different in both groups. Only evening simvastatin administration could significantly decrease hsCRP (p = 0.03). CONCLUSION Simvastatin should be taken in the evening. Although lipid profiles were not statistically different in morning and nighttime simvastatin, the inflammatory marker (hsCRP level) is significantly reduced as a result of evening simvastatin administration.