TY - JOUR
T1 - The effect of the ingestion of Ginkgo biloba extract (EGb 761) on the pharmacokinetics of metformin in non-diabetic and type 2 diabetic subjects-A double blind placebo-controlled, crossover study
AU - Kudolo, George B.
AU - Wang, Wen
AU - Javors, Martin
AU - Blodgett, Janet
N1 - Funding Information:
The nursing and dietetic care provided by the staff of the Frederic C. Bartter General Clinical Research Center at the South Texas Veterans Health Care Systems—Audie Murphy Division is appreciated. This study was supported by funds from NIH grants M01-RR-01346 and R01-AT-00832 (National Center for Complementary and Alternative Medicine, NCCAM). Its contents are solely the responsibility of the authors and do not necessarily represent the official views of the NCCAM, or the National Institutes of Health.
PY - 2006/8
Y1 - 2006/8
N2 - Background & aims: Ginkgo biloba extract (EGb 761) has been shown to ameliorate some defects associated with the insulin resistance syndrome and so patients with Type 2 diabetes mellitus (T2DM) may be inclined to co-ingest the herb with their medications, such as metformin. This study was designed to determine if the co-ingestion of EGb 761 and metformin would alter the pharmacokinetic properties of metformin in T2DM patients and persons without diabetes, who may ingest it for other purposes. Method: Normal glucose tolerance (NGT) subjects (n = 10; age, 39.2±14.0 years; fasting plasma glucose (FPG), 90±7 mg/dl; body mass index (BMI), 24.1±3.7 kg/m2) and 10 T2DM patients (n = 10; age, 51.7±8.9 years; FPG, 150±7 mg/dl; BMI, 33.7±5.7 kg/m2) completed a randomized, double-blind, placebo-controlled crossover study. They ingested either EGb 761 (120 mg/day as a single dose) or a vegetable-based placebo during each arm for 3 months. At the end of each arm, the NGT subject ingested a single 500 mg dose of metformin (non-diabetics) and the T2DM subject took his/her prescribed metformin dose (250-850 mg) with 120 mg EGb 761. Blood and urine samples were collected over an 8-h period, and in the case of T2DM subjects, additionally over the first 2 h of the subsequent 3 days. Results: Ingestion of EGb 761 produced no significant changes in diagnostic laboratory tests in either group, except reducing glycosylated hemoglobin A1c levels (from 7.7±1.2 to 7.2±0.9%, P < 0.05) in T2DM the subjects. The pharmacokinetic parameters of metformin were all significantly different (P < 0.05) between the NGT (500 mg) and 8 out of 10 of the T2DM subjects who were prescribed 500 mg of metformin during the placebo cycles. During the EGb 761 cycles, only the elimination half-life in the T2DM subjects was significantly increased (0.117±0.085 to 0.141±0.100, P < 0.05). Conclusion: The co-ingestion of 120 mg of EGb 761 and 500 mg of metformin did not significantly affect the pharmacokinetic properties of metformin. Further studies are required to verify this observation for smaller and larger dose of metformin with other doses of EGb 761, since T2DM patients on medication constitute a very heterogeneous group.
AB - Background & aims: Ginkgo biloba extract (EGb 761) has been shown to ameliorate some defects associated with the insulin resistance syndrome and so patients with Type 2 diabetes mellitus (T2DM) may be inclined to co-ingest the herb with their medications, such as metformin. This study was designed to determine if the co-ingestion of EGb 761 and metformin would alter the pharmacokinetic properties of metformin in T2DM patients and persons without diabetes, who may ingest it for other purposes. Method: Normal glucose tolerance (NGT) subjects (n = 10; age, 39.2±14.0 years; fasting plasma glucose (FPG), 90±7 mg/dl; body mass index (BMI), 24.1±3.7 kg/m2) and 10 T2DM patients (n = 10; age, 51.7±8.9 years; FPG, 150±7 mg/dl; BMI, 33.7±5.7 kg/m2) completed a randomized, double-blind, placebo-controlled crossover study. They ingested either EGb 761 (120 mg/day as a single dose) or a vegetable-based placebo during each arm for 3 months. At the end of each arm, the NGT subject ingested a single 500 mg dose of metformin (non-diabetics) and the T2DM subject took his/her prescribed metformin dose (250-850 mg) with 120 mg EGb 761. Blood and urine samples were collected over an 8-h period, and in the case of T2DM subjects, additionally over the first 2 h of the subsequent 3 days. Results: Ingestion of EGb 761 produced no significant changes in diagnostic laboratory tests in either group, except reducing glycosylated hemoglobin A1c levels (from 7.7±1.2 to 7.2±0.9%, P < 0.05) in T2DM the subjects. The pharmacokinetic parameters of metformin were all significantly different (P < 0.05) between the NGT (500 mg) and 8 out of 10 of the T2DM subjects who were prescribed 500 mg of metformin during the placebo cycles. During the EGb 761 cycles, only the elimination half-life in the T2DM subjects was significantly increased (0.117±0.085 to 0.141±0.100, P < 0.05). Conclusion: The co-ingestion of 120 mg of EGb 761 and 500 mg of metformin did not significantly affect the pharmacokinetic properties of metformin. Further studies are required to verify this observation for smaller and larger dose of metformin with other doses of EGb 761, since T2DM patients on medication constitute a very heterogeneous group.
KW - Drug-herb interaction
KW - Ginkgo biloba extract
KW - Metformin
KW - Pharmacokinetics
KW - Type 2 diabetes
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U2 - 10.1016/j.clnu.2005.12.012
DO - 10.1016/j.clnu.2005.12.012
M3 - Article
C2 - 16698134
AN - SCOPUS:33746092899
SN - 0261-5614
VL - 25
SP - 606
EP - 616
JO - Clinical Nutrition
JF - Clinical Nutrition
IS - 4
ER -