Effects of Danshen tablets on pharmacokinetics of atorvastatin calcium in rats and its potential mechanism

Context: Danshen tablets (DST), an effective traditional Chinese multi-herbal formula, are often combined with atorvastatin calcium (AC) for treating coronary heart disease in the clinic. Objective: This study investigated the effects of DST on the pharmacokinetics of AC and the potential mechanism. Materials and methods: The pharmacokinetics of AC (1 mg/kg) with or without pretreatment of DST (100 mg/kg) were investigated using LC-MS/MS. The effects of DST (50 μg/mL) on the metabolic stability of AC were also investigated using rat liver microsome incubation systems. Results: The results indicated that C(max) (23.87 ± 4.27 vs. 38.94 ± 5.32 ng/mL), AUC((0–)(t)()) (41.01 ± 11.32 vs. 77.28 ± 12.92 ng h/mL), and t(1/2) (1.91 ± 0.18 vs. 2.74 ± 0.23 h) decreased significantly (p < 0.05) when DST and AC were co-administered, which suggested that DST might influence the pharmacokinetic behavior of AC when they are co-administered. The metabolic stability (t(1/2)) of AC was also decreased (25.7 ± 5.2 vs. 42.5 ± 6.1) with the pretreatment of DST. Discussion and conclusions: This study indicated that the main components in DST could accelerate the metabolism of AC in rat liver microsomes and change the pharmacokinetic behaviors of AC. So these results showed that the herb-drug interaction between DST and AC might occur when they were co-administered. Therefore, the clinical dose of AC should be adjusted when DST and AC are co-administered.