IngentaConnect Effects of green tea extract administration on the pharmacokineti...

Authors: E.H. Jang¹; J.Y. Choi¹; C.S. Park¹; S.-K. Lee¹; C.E. Kim²; H.J. Park¹; J.S. Kang¹; J.W. Lee³; J.H. Kang³

Source: Journal of Pharmacy and Pharmacology, Volume 57, Number 3, March 2005 , pp. 311-316(6)

Abstract:

The pharmacokinetic interaction between clozapine, an atypical antipsychotic with metabolic complications, including weight gain, and green tea consumption has not been evaluated, although green tea is responsible for beneficial effects, including weight reduction, and is widely consumed in the world. Commercial green tea extract (175 mg kg^-1) or saline was administered orally for 4 days before the oral administration of clozapine (20 mg kg^-1 ) to rats. Plasma concentrations of clozapine were measured up to 5 h after clozapine administration, and then hepatic CYP1A2 expression and activity were determined. There was no significant difference in the elimination half-life of clozapine between the green tea extract and saline groups. However, the time to reach peak concentration (T_max) was significantly increased by green tea extract. The mean total area under the plasma concentration–time curve (AUC_0- infin

) and maximal peak plasma concentration (C_max ) of clozapine in the green tea extract group were significantly lower than those of controls. Green tea extract induced a ~2-fold increase in hepatic CYP1A2 levels, while the activity increased slightly (by 10% of control). Because of this reduction in AUC and T_max of clozapine by green tea extract pretreatment, we suggest that both the rate and amount of absorption of clozapine may be reduced by green tea extract, although the hepatic elimination phase may not be significantly altered. Therefore, the clinical implications of the effects of green tea on the bioavailability of clozapine in patients should be further evaluated.

Document Type: Research article

DOI: 10.1211/0022357055687

Affiliations: 1: Department of Pharmacology and Medicinal Toxicology Research Center, CDIR, College of Medicine, Inha Research Institute for Medical Science, Inha University, Incheon, Korea 2: Department of Psychiatry, College of Medicine, Inha University Hospital, Inha University, Incheon, Korea 3: Department of Pharmacology, College of Medicine, Hanyang University, Seoul, Korea

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Effects of green tea extract administration on the pharmacokinetics of clozapine in rats