STUDY OBJECTIVE: . To determine the influence of Echinacea purpurea on the pharmacokinetics of lopinavir-ritonavir and on cytochrome P450 (CYP) 3A and P-glycoprotein activity by using the probe substrates midazolam and fexofenadine, respectively. DESIGN: Open-label, single-sequence pharmacokinetic study. SETTING: Outpatient clinic in a federal government research center. SUBJECTS: Thirteen healthy volunteers (eight men, five women). INTERVENTION: Subjects received lopinavir 400 mg-ritonavir 100 mg twice/day with meals for 29.5 days. On day 16, subjects received E. purpurea 500 mg 3 times/day for 28 days: 14 days in combination with lopinavir-ritonavir and 14 days of E. purpurea alone. In order to assess CYP3A and P-glycoprotein activity, subjects received single oral doses of midazolam 8 mg and fexofenadine 120 mg, respectively, before and after the 28 days of E. purpurea. MEASUREMENTS AND MAIN RESULTS: On days 15 and 30 of lopinavir-ritonavir administration (before and after E. purpurea administration, respectively), serial blood samples were collected over 12 hours to determine lopinavir and ritonavir concentrations and subsequent pharmacokinetic parameters by using noncompartmental methods. Neither lopinavir nor ritonavir pharmacokinetics were significantly altered by 14 days of E. purpurea coadministration. The post-echinacea: pre-echinacea geometric mean ratios (GMRs) for lopinavir area under the concentration-time curve (AUC) from 0-12 hours and for maximum concentration were 0.96 (90% confidence interval [CI] 0.83-1.10, p=0.82) and 1.00 (90% CI 0.88-1.12, p=0.72), respectively. Conversely, GMRs for midazolam AUC from time zero extrapolated to infinity and oral clearance were 0.73 (90% CI 0.61-0.85, p=0.008) and 1.37 (90% CI 1.10-1.63, p=0.02), respectively. Fexofenadine pharmacokinetics did not significantly differ before and after E. purpurea administration (p>0.05). CONCLUSION: Echinacea purpurea induced CYP3A activity but did not alter lopinavir concentrations, most likely due to the presence of the potent CYP3A inhibitor, ritonavir. Echinacea purpurea is unlikely to alter the pharmacokinetics of ritonavir-boosted protease inhibitors but may cause modest decreases in plasma concentrations of other CYP3A substrates.
STUDY OBJECTIVE: . To determine the influence of Echinacea purpurea on the pharmacokinetics of lopinavir-ritonavir and on cytochrome P450 (CYP) 3A and P-glycoprotein activity by using the probe substrates midazolam and fexofenadine, respectively. DESIGN: Open-label, single-sequence pharmacokinetic study. SETTING:Outpatient clinic in a federal government research center. SUBJECTS: Thirteen healthy volunteers (eight men, five women). INTERVENTION: Subjects received lopinavir 400 mg-ritonavir 100 mg twice/day with meals for 29.5 days. On day 16, subjects received E. purpurea 500 mg 3 times/day for 28 days: 14 days in combination with lopinavir-ritonavir and 14 days of E. purpurea alone. In order to assess CYP3A and P-glycoprotein activity, subjects received single oral doses of midazolam 8 mg and fexofenadine 120 mg, respectively, before and after the 28 days of E. purpurea. MEASUREMENTS AND MAIN RESULTS: On days 15 and 30 of lopinavir-ritonavir administration (before and after E. purpurea administration, respectively), serial blood samples were collected over 12 hours to determine lopinavir and ritonavir concentrations and subsequent pharmacokinetic parameters by using noncompartmental methods. Neither lopinavir nor ritonavir pharmacokinetics were significantly altered by 14 days of E. purpurea coadministration. The post-echinacea: pre-echinacea geometric mean ratios (GMRs) for lopinavir area under the concentration-time curve (AUC) from 0-12 hours and for maximum concentration were 0.96 (90% confidence interval [CI] 0.83-1.10, p=0.82) and 1.00 (90% CI 0.88-1.12, p=0.72), respectively. Conversely, GMRs for midazolam AUC from time zero extrapolated to infinity and oral clearance were 0.73 (90% CI 0.61-0.85, p=0.008) and 1.37 (90% CI 1.10-1.63, p=0.02), respectively. Fexofenadine pharmacokinetics did not significantly differ before and after E. purpurea administration (p>0.05). CONCLUSION:Echinacea purpurea induced CYP3A activity but did not alter lopinavir concentrations, most likely due to the presence of the potent CYP3A inhibitor, ritonavir. Echinacea purpurea is unlikely to alter the pharmacokinetics of ritonavir-boosted protease inhibitors but may cause modest decreases in plasma concentrations of other CYP3A substrates.
Authors: Rosa F Yeh; Vincent E Gaver; Kristine B Patterson; Naser L Rezk; Faustina Baxter-Meheux; Michael J Blake; Joseph J Eron; Cheri E Klein; John C Rublein; Angela D M Kashuba Journal: J Acquir Immune Defic Syndr Date: 2006-05 Impact factor: 3.731
Authors: Gene D Morse; Susan Rosenkranz; Michael F Para; Yoninah Segal; Robin Difrancesco; Elizabeth Adams; Barbara Brizz; Kevin E Yarasheski; Richard C Reichman Journal: Antimicrob Agents Chemother Date: 2005-08 Impact factor: 5.191
Authors: Sarah M Robertson; Richard T Davey; Jocelyn Voell; Elizabeth Formentini; Raul M Alfaro; Scott R Penzak Journal: Curr Med Res Opin Date: 2008-02 Impact factor: 2.580
Authors: Mónica M Calderón; Cheryl L Chairez; Lori A Gordon; Raul M Alfaro; Joseph A Kovacs; Scott R Penzak Journal: Pharmacotherapy Date: 2014-08-20 Impact factor: 4.705
Authors: Christine Y Malati; Sarah M Robertson; Jennifer D Hunt; Cheryl Chairez; Raul M Alfaro; Joseph A Kovacs; Scott R Penzak Journal: J Clin Pharmacol Date: 2011-06-06 Impact factor: 3.126
Authors: Andrew K L Goey; Irma Meijerman; Hilde Rosing; Jacobus A Burgers; Marja Mergui-Roelvink; Marianne Keessen; Serena Marchetti; Jos H Beijnen; Jan H M Schellens Journal: Br J Clin Pharmacol Date: 2013-09 Impact factor: 4.335