Pharmacokinetic-interaction of Vitex negundo Linn. & paracetamol.
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Date
2009-10
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Abstract
Background & objectives: Currently, herbal preparations are clinically used as functional food, food
supplements or as add on therapy, which affects the bioavailability and also the net therapeutic potential
of co-administered allopathic drugs. Therefore, it is important to assess the interaction among these two
classes of drugs. Here we studied the interaction between orally-administered ethanolic extract of leaves
of Vitex negundo Linn. (Verbenaceae) (VN extract) and paracetamol in albino rats.
Method: Solvent free dried extract of VN leaves was orally given to experimental rats in different doses
(62.5-1000 mg/kg/b.wt.), daily for six consecutive days. On days 3 and 6, paracetamol (100 mg/kg/b.wt.)
was orally administered to these extract treated rats and control rats (drug vector). At various time
intervals (5 min - 120 min), blood was collected from each animal and paracetamol concentration was
determined in plasma by using HPLC with UV detector at 249 nm. Various pharmacokinetic parameters
were calculated by non compartmental model.
Results:
A significant decline in plasma concentration of paracetamol with time-gap was recorded with
the increasing dose of VN extract, without affecting its Tmax (maximum time to achieve peak plasma
concentration). There was a significant decrease in the extent of absorption and decline in intensity of
therapeutic response (as evidenced by reduced AUC value and decline in Cmax). Further, compared to
control, the relative bioavailability of paracetamol, in presence of VN extract, decreased significantly.
Interpretation & conclusions: VN extract or its ayurvedic formulation if co-administered with allopathic
drug like paracetamol, the dose of allopathic drug needs to be adjusted in order to achieve desired therapeutic response of paracetamol.
Description
Keywords
Bioavailability, herb-drug interaction, paracetamol, pharmacokinetics, Vitex negundo
Citation
Tripathi Yamini Bhusan, Tiwari Om Prakash, Nagwani Santosh, Mishra Brahmeshwar. Pharmacokinetic-interaction of Vitex negundo Linn. & paracetamol. Indian Journal of Medical Research. 2009 Oct; 130(4): 479-483.