Effects of Ginkgo biloba extract ingestion on the pharmacokinetics of talinolol in healthy Chinese volunteers.
BACKGROUND
Ginkgo biloba extract (GBE), the best selling herbal medicine in the world, has been reported to inhibit P-glycoprotein in vitro. However, the effects of GBE on P-glycoprotein activity in humans have not been clarified.


OBJECTIVE
To investigate the effects of single and repeated GBE ingestion on the oral pharmacokinetics of talinolol, a substrate drug for P-glycoprotein in humans.


METHODS
Ten unrelated healthy male volunteers were selected to participate in a 3-stage sequential study. Plasma concentrations of talinolol from 0 to 24 hours were measured by high-performance liquid chromatography after talinolol 100 mg was administrated alone, with a single oral dose of GBE (120 mg), and after 14 days of repeated GBE ingestion (360 mg/day).


RESULTS
A single oral dose of GBE did not affect the pharmacokinetics of talinolol. Repeated ingestion of GBE increased the talinolol maximum plasma concentration (C(max)) by 36% (90% CI 10 to 68; p = 0.025), the area under the concentration-time curve (AUC)(0-24) by 26% (90% CI 11 to 43; p = 0.008) and AUC(0-infinity) by 22% (90% CI 8 to 37; p = 0.014), respectively, without significant changes in elimination half-life and the time to C(max).


CONCLUSIONS
Our results suggest that long-term use of GBE significantly influenced talinolol disposition in humans, likely by affecting the activity of P-glycoprotein and/or other drug transporters.
Fan
Lan
L
Pharmacogenetics Research Institute, Institute of Clinical Pharmacology, Central South University, Changsha, Hunan, China.
Tao
Gong-You
GY
Wang
Guo
G
Chen
Yao
Y
Zhang
Wei
W
He
Yi-Jing
YJ
Li
Qing
Q
Lei
He-Ping
HP
Jiang
Feng
F
Hu
Dong-Li
DL
Huang
Yuan-Fei
YF
Zhou
Hong-Hao
HH
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000378:metabolism; D000319:Adrenergic beta-Antagonists / Q000493:pharmacokinetics; D000328:Adult; D044466:Asian People; D004365:Drugs, Chinese Herbal / Q000008:administration & dosage* / Q000009:adverse effects*; D020441:Ginkgo biloba / Q000009:adverse effects*; D041743:Herb-Drug Interactions; D006801:Humans; D008297:Male; D011412:Propanolamines / Q000493:pharmacokinetics*; D013997:Time Factors
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D000319:Adrenergic beta-Antagonists; D004365:Drugs, Chinese Herbal; D011412:Propanolamines; C011550:talinolol