Abstract: OBJECTIVE To investigate the influences of five dihydropyridin calcium antagonists on the metabolism of lovastatin. METHODS The lovastatin was incubated with different concentrations of nifedipine felodipin, lacidipine, lercanidipine, and nimodipine in rat liver microsomes in vitro. The metabolic reaction was started by adding NADP/NADPH (0.9 mmol·L^-1/0.2 mmol·L^-1) after microsomal incubates being prewarmed for 5 min, continued at 37 ℃ for several periods in a shaking water bath. Then the reaction was terminated and protein was precipitated by ice acetonitrile. After the super-speed centrifugation, the supernatant was analyzed by HPLC. The inhibition parameters (IC₅₀) were calculated. RESULTS The results indicated that different dihydropyridin calcium antagonists showed different influences on the metabolism of lovastatin. The inhibition of nifedipine was mild weakest (IC₅₀=53.98 μmol·L^-1), and nimodipine was strongest(IC₅₀=2.01 μmol·L^-1). The structural analysis indicated that the LogP was positively correlated with the IC50, otherwise, the mass amu and surface area grid were negatively correlated. CONCLUSION When lovastatin and dihydropyridin calcium antagonists were administered together to treat dyslipidemia and hypertension simutanously, drug interactions with significant clinical consequences may occur. And we should choose the dihydropyridin calcium antagonist with the greater LogP and less mass amu, surface area grid, such as nifedipine and felodipin.