The chronologic effects of atorvastatin: Morning versus evening administration in hyperlipidemic adults

Objective. To compare the lipid lowering effects [total cholesterol (Total-C), low-density lipoprotein cholesterol (LDL-C), triglycerides (TG), and high-density lipoprotein cholesterol (HDL-C)], of a morning dose (before 12 PM) and an evening dose (after 6 PM and before 12 AM) of atorvastatin 40 mg, in veteran patients diagnosed with hyperlipidemia.;Methods. Sixty-four male patients, over the age of 50, from the New York Veterans Administration Harbor Health Care System (NYVAHHCS) ambulatory care clinic, were retrospectively (58 patients), and prospectively (6 patients), enrolled and evaluated. In the retrospective study, data on drug dosing, time of administration, and lipoprotein profiles were obtained from computerized records. Twenty-nine patients who received atorvastatin in the morning were compared to 29 patients who received atorvastatin in the evening. As for the patients prospectively enrolled, each patient was randomized to receive atorvastatin in the morning or in the evening. The baseline serum lipid parameters were compared to the follow-up values. Patients were excluded from the study if they were receiving any antihyperlipidemic medications other than atorvastatin, started on medications known to affect lipids (within last 4 months), and/or newly diagnosed with a disease known to affect serum lipoproteins. The various serum lipoprotein profiles for each patient were obtained for analysis. The two-tailed Student's t-test was utilized to compare the mean percent reduction in the lipid parameters between morning and evening atorvastatin administration. Statistical significance was set at 95 with a p < 0.05.;Results. Retrospective Study. The percent reduction following morning and evening atorvastatin administration were as follows: Total-C levels 34.7% vs 34.6% (p = .504), LDL-C levels 47.6% vs 46.6% (p = .942), TG levels 29.5% vs 28.1% (p = 0.228), respectively. The percent increase in HDL-C following morning and evening administration was 7.3 vs 7.6% (p = 0.331), respectively.;Prospective Study. The percent reduction following morning and evening atorvastatin administration were as follows: Total-C levels 34.5% vs 35%, LDL-C levels 47.2% vs 46.9%, TG levels 24.1% vs 25.7%, respectively. The percent increase in HDL-C following morning and evening administration was 4.8% vs 2.6%, respectively.;Conclusion. No statistically significant differences were found between the group that received atorvastatin in the morning versus the group that received atorvastatin in the evening. Morning and evening atorvastatin administration equally reduced the serum Total-C, LDL-C, and TG levels and equally increased serum HDL-C levels. The findings of this study indicate that atorvastatin exerts a similar effect on the lipoprotein parameters regardless of administration time.