Pharmacokinetic interactions study between carvedilol and some antidepressants in rat liver microsomes - a comparative study.

BACKGROUND AND AIMS: Cardiovascular diseases and depressive disorders are some of the most frequent diseases. The probability of concomitant prescription of antihypertensive and antidepressive medication is increasing. The aim of this study was to investigate the enzyme inhibition by bupropion, sertraline and fluvoxamine on the metabolism of carvedilol using rat pooled liver microsomes and to assess the importance of these interactions from the pharmacokinetic mechanism point of view. METHODS: Two substrate concentrations (0.5 and 1 µM) and four inhibitor concentrations (0, 0.1, 0.75 and 1.5 µM) were used for each tested inhibitor. RESULTS: The results of the in vitro experiments showed a significant decrease of the metabolic rate of carvedilol to 4'-hydroxyphenyl carvedilol, for all tested inhibitors, when the inhibitor was added to the incubation mixture containing the substrate. Moreover, an increase of the area under the concentration-time curve for carvedilol was observed after incubation with each tested inhibitor compared with the control state (no inhibitor). The most potent inhibitor was sertraline, followed by fluvoxamine and bupropion. CONCLUSION: The co-administration of tested antidepressants led to a significant alteration of carvedilol's metabolism in vitro. CYP2D6 inhibition is the main pharmacokinetic mechanism that can explain these drug-drug interactions, with possible clinical implications.

Inhibitory Effect of Citalopram on the Pharmacokinetics of Carvedilol in Rats and in vitro Models.

BACKGROUND/AIMS: The aim of this study was to investigate the drug-drug interaction between carvedilol and citalopram based on carvedilol metabolism in vitro and his pharmacokinetics (PKs) in vivo after the oral administration of the single drug and both drugs, and reveal citalopram effects on the PKs of carvedilol. METHODS: Each rat was cannulated on the femoral vein, prior to being connected to BASi Culex ABC®. Carvedilol was orally administrated in rats (3.57 mg/kg body weight [b.w.]) in the absence of citalopram or after a pre-treatment with multiple oral doses of citalopram (1.42 mg/kg b.w.). Plasma concentrations of carvedilol were determined using high-performance liquid chromatography-MS at the designated time points after drug administration, and the main PK parameters were calculated by noncompartmental analysis. In addition, effects of citalopram on the metabolic rate of carvedilol were investigated using rat-pooled liver microsome incubation systems. RESULTS: During co-administration, significant increases of the area under the plasma concentration-time curve as well as of the peak plasma concentration were observed. The rat-pooled liver microsome incubation experiment indicated that citalopram could decrease the metabolic rate of carvedilol. CONCLUSION: Citalopram co-administration led to a significant alteration of carvedilol's PK profile in rats; it also demonstrated, in vitro, these effects could be explained by the existence of a drug-drug interaction mediated by CYP2D6 inhibition.

The Pharmacokinetic Interaction Study between Carvedilol and Bupropion in Rats.

BACKGROUND/AIMS: The effects of multiple-dose bupropion on the pharmacokinetics of single-dose carvedilol were investigated in order to evaluate this possible drug-drug interaction. METHODS: A preclinical study was conducted among white male Wistar rats. Each rat was cannulated on the femoral vein prior to being connected to BASi Culex ABC®. During the reference period, each rat received an intravenous and an oral dose of 3.57 mg/kg body weight (b.w.) carvedilol, at 2 days distance. After 5 days of pretreatment with 21.42 mg/kg b.w. bupropion (by oral route, twice a day - given in order to reach the steady state), during the sixth day, 3.57 mg/kg b.w. carvedilol and 21.42 mg/kg b.w. bupropion were orally co-administrated (test period). After each administration of carvedilol, several samples of 200 µL blood were collected. The pharmacokinetic parameters of carvedilol were analyzed by the noncompartmental method. RESULTS: The 5 days pretreatment with bupropion increased the exposure to carvedilol in rats by 180%, considering the modifications observed in the area under the curve of carvedilol. Carvedilol was shown to have higher plasma concentrations, delay in maximum concentration, and a prolonged half-life, after being pretreated with bupropion. CONCLUSION: The administration of multiple-dose bupropion influences the pharmacokinetics of carvedilol (single oral dose) in rats.