Aim To compare the effects of morning versus evening intake of simvastatin on lipid profile and high-sensitivity C-reactive protein(hs-CRP) in patients with combined hyperlipidemia.Methods103 patients were randomly assigned to receive 20 mg simvastatin orally each morning(n=52) or evening(n=51).The treatment period lasted 6 months.Lipid profiles,physical and laboratory investigations for adverse effects,and hs-CRP were assessed.ResultsSerum total cholesterol(TC),low density lipoprotein cholesterol(LDLC) and triglyceride(TG) levels decreased significantly in both treatment groups,while simvastatin in the morning administration resulted in larger reductions in TG than dose evening administration(38% vs 19%,P=0.035).Moreover,morning administration reduced TC and LDLC by 21% and 31%,respectively.The success rates of TG and all three together(TC,LDLC and TG) were 51% and 36% in the morning administration,which were superior to the drug given in the evening(33% and 29%,respectively).Although serum hs-CRP levels decreased significantly from baseline in both morning and evening administration,similar hs-CRP reductions were observed between the two treatment groups(p<0.05).And the effects were cholesterolindependent.There were no adverse events during the treatment periods,and simvastatin was well tolerated in the morning or evening administration.ConclusionsThe results demonstrated that TG lowering effects of simvastatin in the morning administration were superior to that of evening administration.There is no diurnal variation in anti-inflammatory effects of this drug,therefore,morning or evening administration is equally effective in decreasing hs-CRP.