Effect of Cinnamomum verum Extract on the Pharmacokinetics and Pharmacodynamics of Amlodipine in Hypertensive Rats

Abstract

Context: Hyperlipidaemia and hypertension are often treated together with Cinnamomum verum and amlodipine. It is necessary to investigate the drug-drug interaction between Cinnamomum verum and amlodipine.
Objective: Cinnamomum verum and amlodipine interaction was investigated in rats and with rat liver microsomes.
Methods: The pharmacokinetics of amlodipine (1 mg/kg) was investigated in rats with or without Cinnamomum verum pre-treatment (2 mg/kg), six rats in each group. The metabolic stability of amlodipine was investigated with rat liver microsomes.
Results: Cinnamomum verum significantly increased the Cmax (28.18 ± 1.91 versus 19.90 ± 1.86 lg/L), AUC(0-t) (486.29 ± 70.16 versus 274.56 ± 78.78 lgh/L), and t1/2 (16.76 ± 1.94 versus 16.57 ± 2.40 h) of amlodipine (p < 0.05). The metabolic stability of amlodipine was significantly increased with the half-life time in rat liver microsomes increased from 36.78 ± 4.28 to 45.76 ± 7.56 min, and the intrinsic rate decreased from 56.13 ± 2.29 to 43.19 ± 3.67 lL/min/mg protein.
Discussion and conclusions: These results indicated that drug-drug interaction might appear during the co-administration of Cinnamomum verum and amlodipine. The potential mechanism may be due to the inhibition of CYP3A4 by Cinnamomum verum. Thus, this interaction should be given special attention in the clinic and needs further experiments to characterize the effect in humans.