title: Effects of ephedra water decoction and cough tablets containing ephedra and liquorice on CYP1A2 and the pharmacokinetics of theophylline in rats.
abstract: Ephedra water decoction (EWD) and cough tablets containing ephedra and liquorice (maxing cough tablets, MXCT) have been used widely in the treatment of asthma. In the clinic, EWD and MXCT may be prescribed with theophylline, one of the most popular antiasthmatic drugs and a typical substrate of cytochrome P450 (CYP) 1A2. So in the present study the potential effects of EWD and MXCT on CYP1A2 activity and the pharmacokinetics of theophylline in rats were evaluated. In the in vivo CYP1A2 activity research, the rats were given oral caffeine (10 mg/kg) after a 14 day pretreatment with EWD (18 g/kg) and MXCT (0.1, 0.2 or 0.4 g/kg). Then the CYP 1A2 activity was expressed by using the caffeine metabolic ratio (CMR). The results showed that the CMR increased markedly compared with the control groups. In the pharmacokinetics experiment, the rats were given oral theophylline (10 mg/kg) after a 14 day pretreatment with EWD (18 g/kg) and MXCT (0.2 g/kg). The results showed that the AUC(0-24 h) and C(max) of theophylline were reduced markedly compared with the control groups. These results demonstrated that EWD or MXCT pretreatment obviously induced CYP1A2 activity, therefore, speeding up the metabolism of theophylline. The concomitant use of EWD or MXCT may decrease the effect of theophylline in rats.
authors.affiliation: Department of Pharmaceutics, School of Pharmacy, Harbin Medical University, Harbin 150086, China.
authors.forename: Jingling
authors.initials: J
authors.lastname: Tang
authors.forename: Xiaoyan
authors.initials: X
authors.lastname: Zhou
authors.forename: Hongyu
authors.initials: H
authors.lastname: Ji
authors.forename: Daling
authors.initials: D
authors.lastname: Zhu
authors.forename: Linhua
authors.initials: L
authors.lastname: Wu
mesh_terms: D000818:Animals; D002110:Caffeine / Q000008:administration & dosage; D019388:Cytochrome P-450 CYP1A2 / Q000737:chemistry*; D065609:Cytochrome P-450 CYP1A2 Inhibitors; D004789:Enzyme Activation; D004791:Enzyme Inhibitors / Q000737:chemistry / Q000494:pharmacology; D029789:Ephedra / Q000737:chemistry*; D006035:Glycyrrhiza / Q000737:chemistry*; D008099:Liver / Q000737:chemistry / Q000187:drug effects / Q000201:enzymology; D008297:Male; D011897:Random Allocation; D051381:Rats; D017208:Rats, Wistar; D013607:Tablets / Q000737:chemistry; D013806:Theophylline / Q000008:administration & dosage / Q000737:chemistry / Q000493:pharmacokinetics*; D013997:Time Factors; D014867:Water / Q000737:chemistry
chemical_list: D065609:Cytochrome P-450 CYP1A2 Inhibitors; D004791:Enzyme Inhibitors; D013607:Tablets; D014867:Water; D002110:Caffeine; D013806:Theophylline; D019388:Cytochrome P-450 CYP1A2