Rate of Low‐Density Lipoprotein Cholesterol and Apolipoprotein B Changes on Initiation and Discontinuation of Atorvastatin Treatment

In a clinical trial, the changes in LDL cholesterol and in total apolipoprotein B with time were analyzed using a one-compartment model with constant input rate and first-order elimination rate constant after the initiation and discontinuation of treatment with atorvastatin. After initiation of treatment, input rate for total apoplipoprotein B (21 mg/dL/day) and elimination rate constants for both total apoplipoprotein B (0.36 days -1 ) and low-density lipoprotein (LDL) cholesterol (0.24 days -1 were similar to those reported for LDL-apolipoprotein B at steady state during treatment with other HMG-CoA reductase inhibitors. However, after discontinuation of treatment, very low elimination rate constants of 0.09 days ' for LDL cholesterol and 0.07 days -1 for total apolipoprotein B are obtained. A likely explanation is that the model incorrectly assumes an immediate return to the pretreatment state, whereas transient stimulation of hepatic cholesterol synthesis on discontinuation of therapy with HMG-CoA reductase inhibitors is known to occur.