Herb-drug InteractionsPhase 1NCT07823140
Effects of Kudzu Root (Gegen) on Drug-Metabolizing Enzymes and Blood Clotting in Healthy Volunteers
A Phase 1 study testing Arm 1: Radix Puerariae lobatae (Gegen), Arm 1: Six-probe drug cocktail and Arm 2: Radix Puerariae lobatae (Gegen) in people with Herb-drug Interactions, run by Chinese University of Hong Kong at 1 site in Hong Kong.
Trial summary
Purpose: The purpose of this study is to understand how the traditional herbal medicine kudzu root (Gegen, Radix Puerariae lobatae) affects the activity of drug metabolizing enzymes in the body, and whether this could lead to interactions with other medicines. Read more about this study
- Who is it for?
- Ages 20 to 45 yearsHealthy volunteers can take part
- Conditions the study is for
- Herb-drug Interactions
- What is being tested?
- Arm 1: Radix Puerariae lobatae (Gegen), Arm 1: Six-probe drug cocktail and Arm 2: Radix Puerariae lobatae (Gegen)
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 56 participants
- Where
- 1 siteHong Kong
- Study dates
- 8 Aug 2022to 28 Apr 2023
- Phase
- Phase 1
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 20 to 45 years
- All sexes
- Healthy volunteers accepted
- Adult
Who may be able to join
- Male and non-pregnant female Chinese subjects, 20 - 45 years of age.
- Body weight within 15% of ideal weight (according to the Metropolitan Insurance Company Bulletin).
- Accessible vein for blood sampling.
- High probability for compliance and completion of the study.
- Female subjects who are surgically sterile or post-menopausal. Or female subjects of child bearing potential agree to practice abstinence or take effective contraceptive methods (e.g. non-hormonal intra-uterine device, consistent condom plus spermicide use or consistent cervical cap with spermicide) from the start of screening until two weeks of last dose administration to prevent pregnancy.
- Male subjects agree to practice abstinence or take effective contraceptive method (refer to the aforementioned) from the start of screening until two weeks of last dose administration to prevent his partner pregnant.
- Subjects agree to abstain from any prescription or non-prescription medications 2 weeks before the first dosing and throughout the study (except those allowed based on investigator's judgement).
- Have signed the written informed consent to participate in the study.
Who cannot join
- Clinically significant hepatic, renal, biliary, cardiovascular, gastrointestinal, haematological and other chronic and acute diseases within 3 months prior to the study.
- Clinically significant abnormality in physical examination, ECG evaluation, urine test, blood chemistry or haematological test.
- Tobacco uses in any forms.
- Positive results of hepatitis B.
- Regular consumer of alcohol (on average more than one drink per day within 1 month prior to the start of first dosing).
- Consumer of Asian vegetables, fruits or other herb medicine which are known to contain moderate to high levels of furanocoumarins, such as grapefruit juice, or herbal teas that naturally contain coumadin or coumadin-like substances such as Chamomile tea.
Show all 15Show fewer
- Have lost or donate more than 350 ml blood donation within 4 weeks prior to the start of the study.
- Administer any prescription or non-prescription medications which is likely to be required during the course of the study (except those allowed based on investigator's judgement).
- Treatment of Gegen or the studied probe drugs (caffeine, losartan, omeprazole, metoprolol, midazolam, efavirenz) within 2 weeks before the study.
- Volunteer in any clinical drug study within 1 month prior to this study
- History of allergy or hypersensitivity to Gegen or the studied probe drugs (caffeine, losartan, omeprazole, metoprolol, midazolam, efavirenz) and other drugs in its class.
- History of drug abuse in any form.
- Female subjects who are breastfeeding or pregnancy.
- Subjects who are considered not suitable in participating the study due to other unfavourable factors determined by investigators.
- History or presence of problem in swallowing capsules and/or Chinese medicine.
Trial locations and contacts
1 site in 1 country.
Hong Kong1 site
The Chinese University of Hong Kong Phase 1 Clinical Trial Centre
Hong Kong
About this study
Official title: Clinical Evaluations of CYP 450 Inhibition and Anticoagulation Biomarker Alteration by Radix Puerariae Lobatae (Gegen): Impact on Its Potential Herb-drug Interactions
Purpose:
The purpose of this study is to understand how the traditional herbal medicine kudzu root (Gegen, Radix Puerariae lobatae) affects the activity of drug metabolizing enzymes in the body, and whether this could lead to interactions with other medicines.
Read more
Background:
Many medicines are broken down in the body by enzymes called cytochrome P450 (CYP) enzymes. Preclinical data suggest that Gegen can inhibit CYP enzymes, which may lead to herb-drug interactions; however, robust clinical evidence in humans remains insufficient.
Participants:
This study recruited 56 healthy Chinese adults, who were randomly assigned to parallel low and high dose Gegen groups; 52 participants finished the study.
Interventions:
Participants took a mixture of probe medicines known as a CYP probe cocktail to measure baseline CYP enzyme activity. After receiving either low or high dose Gegen, they received the probe cocktail again to detect changes in enzyme activity. Blood samples were collected to test the probe medicines, their breakdown products, and markers for blood clotting and blood vessel health.
Outcome Measures:
Primary outcomes include changes in blood levels and metabolic ratios of probe medicines. These values reflect differences in CYP enzyme activity with and without Gegen, and are compared across low and high dose groups.
Hypothesis:
The study hypothesized that Gegen alters CYP enzyme activity, and that the magnitude of this effect varies with Gegen dose.
Read the detailed description
Gegen (Radix Puerariae lobatae) is a common traditional Chinese herbal medicine. Preclinical data indicate its potential to inhibit cytochrome P450 enzymes, which may lead to herb-drug interactions. However, robust clinical evidence in humans remains insufficient.This randomized, two-period study enrolled healthy Chinese adults, with participants allocated to parallel low-dose and high-dose Gegen groups. A six-probe drug cocktail was administered before and after Gegen intake to characterize in vivo CYP enzyme activity under intervention and control conditions.Serial blood samples were collected to quantify probe substrates and metabolites for CYP phenotyping, and to measure circulating biomarkers of coagulation and endothelial function for safety assessment. This study evaluated Gegen's effects on six key human CYP isoforms (CYP1A2, CYP2B6, CYP2C9, CYP2C19, CYP2D6 and CYP3A). Enzyme activity was assessed using metabolic ratios and AUC-based drug exposure comparisons. Specific coagulation and endothelial biomarkers, including thromboxane B2 and soluble thrombomodulin, were examined. Adverse events were monitored throughout the study.The results of this study provide insight into the isoform-specific modulation of CYP enzymes by Gegen and its potential implications for herb-drug interactions involving CYP-metabolized medications.
- Conditions
- Herb-drug Interactions
- Being tested
- Arm 1: Radix Puerariae lobatae (Gegen), Arm 1: Six-probe drug cocktail, Arm 2: Radix Puerariae lobatae (Gegen), Arm 2: Six-probe drug cocktail
- Keywords
- Kudzu root, Gegen, Pueraria lobata, Herb-drug interaction, Cytochrome P450, CYP2C19, Probe drug cocktail, Traditional Chinese medicine
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Arm 1: Radix Puerariae lobatae (Gegen)Drug
Also called Puerariae Lobatae Radix, Kudzu Root, Lobed Kudzuvine Root
Granules of the dried root of Pueraria lobata (listed in the Hong Kong Chinese Materia Medica Standards; Chinese Pharmacopoeia monograph Radix Puerariae Lobatae).
Arm 1: Six-probe drug cocktailDrug
Also called caffeine, efavirenz, losartan, omeprazole
Single oral dose of a cocktail comprising caffeine (CYP1A2), efavirenz (CYP2B6), losartan (CYP2C9), omeprazole (CYP2C19), metoprolol (CYP2D6), and midazolam (CYP3A4).
Arm 2: Radix Puerariae lobatae (Gegen)Drug
Also called Puerariae Lobatae Radix, Kudzu Root, Lobed Kudzuvine Root
Granules of the dried root of Pueraria lobata (listed in the Hong Kong Chinese Materia Medica Standards; Chinese Pharmacopoeia monograph Radix Puerariae Lobatae).
Arm 2: Six-probe drug cocktailDrug
Also called caffeine, efavirenz, losartan, omeprazole
Single oral dose of a cocktail comprising caffeine (CYP1A2), efavirenz (CYP2B6), losartan (CYP2C9), omeprazole (CYP2C19), metoprolol (CYP2D6), and midazolam (CYP3A4).
| Study group | Role | What they receive |
|---|---|---|
| Low dose Gegen | Experimental | Participants received the low-dose (3.3 g) Gegen regimen for 14 days; the six-probe drug cocktail was administered once before (Session I, baseline) and once after (Session II) Gegen dosing for CYP phenotyping. Receives: Drug: Arm 1: Radix Puerariae lobatae (Gegen); Drug: Arm 1: Six-probe drug cocktail |
| High dose Gegen | Experimental | Participants received the high-dose (5 g) Gegen regimen for 14 days; the six-probe drug cocktail was administered once before (Session I, baseline) and once after (Session II) Gegen dosing for CYP phenotyping. Receives: Drug: Arm 2: Radix Puerariae lobatae (Gegen); Drug: Arm 2: Six-probe drug cocktail |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change in CYP1A2 phenotypic activity
Plasma concentrations of caffeine and its metabolite paraxanthine were quantified by validated LC-MS/MS. CYP1A2 activity was expressed as the AUC0-t derived metabolite-to-parent ratio (unit of measure: ratio).
Measured: Session I (baseline) and Session II (after 14 days of Gegen administration); within each session, blood samples were collected at pre-dose (0 hour) and 0.25, 0.5, 0.75, 1, 2, 3, 4, 6, 8, 12, 24, 48, and 72 hours after dosing of cocktail probe drugs.
Change in CYP2B6 phenotypic activity
Plasma concentrations of efavirenz and its metabolite 8-Hydroxy-efavirenz were quantified by validated LC-MS/MS. CYP1A2 activity was expressed as the AUC0-t derived metabolite-to-parent ratio (unit of measure: ratio).
Measured: Session I (baseline) and Session II (after 14 days of Gegen administration); within each session, blood samples were collected at pre-dose (0 hour) and 0.25, 0.5, 0.75, 1, 2, 3, 4, 6, 8, 12, 24, 48, and 72 hours after dosing of cocktail probe drugs.
Change in CYP2C9 phenotypic activity
Plasma concentrations of losartan and its metabolite E-3174 were quantified by validated LC-MS/MS. CYP1A2 activity was expressed as the AUC0-t derived metabolite-to-parent ratio (unit of measure: ratio).
Measured: Session I (baseline) and Session II (after 14 days of Gegen administration); within each session, blood samples were collected at pre-dose (0 hour) and 0.25, 0.5, 0.75, 1, 2, 3, 4, 6, 8, 12, 24, 48, and 72 hours after dosing of cocktail probe drugs.
Change in CYP2C19 phenotypic activity
Plasma concentrations of omeprazole and its metabolite 5-Hydroxy-omeprazole were quantified by validated LC-MS/MS. CYP1A2 activity was expressed as the AUC0-t derived metabolite-to-parent ratio (unit of measure: ratio).
Measured: Session I (baseline) and Session II (after 14 days of Gegen administration); within each session, blood samples were collected at pre-dose (0 hour) and 0.25, 0.5, 0.75, 1, 2, 3, 4, 6, 8, 12, 24, 48, and 72 hours after dosing of cocktail probe drugs.
Change in CYP2D6 phenotypic activity
Plasma concentrations of metoprolol and its metabolite α-Hydroxy-metoprolol were quantified by validated LC-MS/MS. CYP1A2 activity was expressed as the AUC0-t derived metabolite-to-parent ratio (unit of measure: ratio).
Measured: Session I (baseline) and Session II (after 14 days of Gegen administration); within each session, blood samples were collected at pre-dose (0 hour) and 0.25, 0.5, 0.75, 1, 2, 3, 4, 6, 8, 12, 24, 48, and 72 hours after dosing of cocktail probe drugs.
Change in CYP3A4 phenotypic activity
Plasma concentrations of midazolam and its metabolite 1'-Hydroxy-midazolam were quantified by validated LC-MS/MS. CYP1A2 activity was expressed as the AUC0-t derived metabolite-to-parent ratio (unit of measure: ratio).
Measured: Session I (baseline) and Session II (after 14 days of Gegen administration); within each session, blood samples were collected at pre-dose (0 hour) and 0.25, 0.5, 0.75, 1, 2, 3, 4, 6, 8, 12, 24, 48, and 72 hours after dosing of cocktail probe drugs.
Change in thromboxane B2 concentration
Plasma concentration of thromboxane B2, a biomarker of platelet activation and coagulation, was quantified by enzyme-linked immunosorbent assay (unit of measure: ng/mL).
Measured: Blood samples collected at pre-dose (0 hour) in Session I (baseline) and 72 hours post-cocktail-dose in Session II (after 14 days of Gegen dosing)
Change in soluble thrombomodulin concentration
Plasma concentration of soluble thrombomodulin, a biomarker of endothelial function, was quantified by enzyme-linked immunosorbent assay (unit of measure: ng/mL).
Measured: Blood samples collected at pre-dose (0 hour) in Session I (baseline) and 72 hours post-cocktail-dose in Session II (after 14 days of Gegen dosing)
Change in prothrombin time
Plasma prothrombin time, a coagulation parameter, was measured by standard clotting assay on an automated coagulometer (unit of measure: seconds).
Measured: Blood samples collected at pre-dose (0 hour) in Session I (baseline) and 72 hours post-cocktail-dose in Session II (after 14 days of Gegen dosing)
Secondary outcomes (1)
Incidence of adverse events
Number and percentage of participants with at least one adverse event, assessed by physical examination (general appearance, skin, head, eye, ear, nose, throat, neck, heart, chest, central neurologic system, abdomen, extremity), vital signs (body temperature, pulse, respirations, sitting systolic and diastolic pressures), 12-lead electrocardiogram (heart rate, PR interval, QRS duration, QT interval), and laboratory safety tests (haematology, blood chemistry, urinalysis).
Measured: From enrolment until the final visit (72 hours after the Session II probe cocktail administration)
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted16 Sep 2026
- Study start8 Aug 2022
- Primary completion21 Apr 2023
- Study completion28 Apr 2023
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Herb-drug InteractionsStudies of the same condition, open and under way.
- More trials run by Chinese University of Hong KongThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 1
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Enrolment
- 56 participants (actual)
Sponsor and investigators
- Lead sponsor
- Chinese University of Hong Kong
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Zhong Zuo, Chinese University of Hong Kong
- Investigators
- Zhong Zuo, PhD, Principal investigator, Chinese University of Hong Kong
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07823140
- Sponsor's protocol ID
- ZUO-P19-004
- Status last verified
- Sep 2026
- First submitted
- 4 Sep 2026
- Last updated
- 5 Oct 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No: Dataset includes identifiable genotype information.
Study at a glance
From the registry record, last updated by the sponsor on 5 Oct 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Clinical Evaluations of CYP 450 Inhibition and Anticoagulation Biomarker Alteration by Radix Puerariae Lobatae (Gegen): Impact on Its Potential Herb-drug Interactions
- ClinicalTrials.gov ID
- NCT07823140
- Acronym / sponsor ID
- ZUO-P19-004
- Conditions
- Herb-drug Interactions
- Keywords
- Kudzu root, Gegen, Pueraria lobata, Herb-drug interaction, Cytochrome P450, CYP2C19, Probe drug cocktail, Traditional Chinese medicine
- Phase
- Phase 1
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 56 participants (actual)
- Lead sponsor
- Chinese University of Hong KongUniversity, hospital or other
- Study start
- 8 Aug 2022 (actual)
- Primary completion
- 21 Apr 2023 (actual)
- Study completion
- 28 Apr 2023 (actual)
- First posted
- 16 Sep 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Purpose:
The purpose of this study is to understand how the traditional herbal medicine kudzu root (Gegen, Radix Puerariae lobatae) affects the activity of drug metabolizing enzymes in the body, and whether this could lead to interactions with other medicines.
Background:
Many medicines are broken down in the body by enzymes called cytochrome P450 (CYP) enzymes. Preclinical data suggest that Gegen can inhibit CYP enzymes, which may lead to herb-drug interactions; however, robust clinical evidence in humans remains insufficient.
Participants:
This study recruited 56 healthy Chinese adults, who were randomly assigned to parallel low and high dose Gegen groups; 52 participants finished the study.
Interventions:
Participants took a mixture of probe medicines known as a CYP probe cocktail to measure baseline CYP enzyme activity. After receiving either low or high dose Gegen, they received the probe cocktail again to detect changes in enzyme activity. Blood samples were collected to test the probe medicines, their breakdown products, and markers for blood clotting and blood vessel health.
Outcome Measures:
Primary outcomes include changes in blood levels and metabolic ratios of probe medicines. These values reflect differences in CYP enzyme activity with and without Gegen, and are compared across low and high dose groups.
Hypothesis:
The study hypothesized that Gegen alters CYP enzyme activity, and that the magnitude of this effect varies with Gegen dose.
Detailed description
Gegen (Radix Puerariae lobatae) is a common traditional Chinese herbal medicine. Preclinical data indicate its potential to inhibit cytochrome P450 enzymes, which may lead to herb-drug interactions. However, robust clinical evidence in humans remains insufficient.This randomized, two-period study enrolled healthy Chinese adults, with participants allocated to parallel low-dose and high-dose Gegen groups. A six-probe drug cocktail was administered before and after Gegen intake to characterize in vivo CYP enzyme activity under intervention and control conditions.Serial blood samples were collected to quantify probe substrates and metabolites for CYP phenotyping, and to measure circulating biomarkers of coagulation and endothelial function for safety assessment. This study evaluated Gegen's effects on six key human CYP isoforms (CYP1A2, CYP2B6, CYP2C9, CYP2C19, CYP2D6 and CYP3A). Enzyme activity was assessed using metabolic ratios and AUC-based drug exposure comparisons. Specific coagulation and endothelial biomarkers, including thromboxane B2 and soluble thrombomodulin, were examined. Adverse events were monitored throughout the study.The results of this study provide insight into the isoform-specific modulation of CYP enzymes by Gegen and its potential implications for herb-drug interactions involving CYP-metabolized medications.
Study design
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Low dose Gegen | Experimental | Drug: Arm 1: Radix Puerariae lobatae (Gegen), Drug: Arm 1: Six-probe drug cocktailParticipants received the low-dose (3.3 g) Gegen regimen for 14 days; the six-probe drug cocktail was administered once before (Session I, baseline) and once after (Session II) Gegen dosing for CYP phenotyping. |
| High dose Gegen | Experimental | Drug: Arm 2: Radix Puerariae lobatae (Gegen), Drug: Arm 2: Six-probe drug cocktailParticipants received the high-dose (5 g) Gegen regimen for 14 days; the six-probe drug cocktail was administered once before (Session I, baseline) and once after (Session II) Gegen dosing for CYP phenotyping. |
Who may qualify
- Ages
- 20 to 45 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (8 listed)
- Male and non-pregnant female Chinese subjects, 20 - 45 years of age.
- Body weight within 15% of ideal weight (according to the Metropolitan Insurance Company Bulletin).
- Accessible vein for blood sampling.
- High probability for compliance and completion of the study.
- Female subjects who are surgically sterile or post-menopausal. Or female subjects of child bearing potential agree to practice abstinence or take effective contraceptive methods (e.g. non-hormonal intra-uterine device, consistent condom plus spermicide use or consistent cervical cap with spermicide) from the start of screening until two weeks of last dose administration to prevent pregnancy.
Key exclusion criteria (15 listed)
- Clinically significant hepatic, renal, biliary, cardiovascular, gastrointestinal, haematological and other chronic and acute diseases within 3 months prior to the study.
- Clinically significant abnormality in physical examination, ECG evaluation, urine test, blood chemistry or haematological test.
- Tobacco uses in any forms.
- Positive results of hepatitis B.
- Regular consumer of alcohol (on average more than one drink per day within 1 month prior to the start of first dosing).
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Arm 1: Radix Puerariae lobatae (Gegen)Also: Puerariae Lobatae Radix, Kudzu Root, Lobed Kudzuvine RootGranules of the dried root of Pueraria lobata (listed in the Hong Kong Chinese Materia Medica Standards; Chinese Pharmacopoeia monograph Radix Puerariae Lobatae). | Drug | Low dose Gegen |
| Arm 1: Six-probe drug cocktailAlso: caffeine, efavirenz, losartan, omeprazoleSingle oral dose of a cocktail comprising caffeine (CYP1A2), efavirenz (CYP2B6), losartan (CYP2C9), omeprazole (CYP2C19), metoprolol (CYP2D6), and midazolam (CYP3A4). | Drug | Low dose Gegen |
| Arm 2: Radix Puerariae lobatae (Gegen)Also: Puerariae Lobatae Radix, Kudzu Root, Lobed Kudzuvine RootGranules of the dried root of Pueraria lobata (listed in the Hong Kong Chinese Materia Medica Standards; Chinese Pharmacopoeia monograph Radix Puerariae Lobatae). | Drug | High dose Gegen |
| Arm 2: Six-probe drug cocktailAlso: caffeine, efavirenz, losartan, omeprazoleSingle oral dose of a cocktail comprising caffeine (CYP1A2), efavirenz (CYP2B6), losartan (CYP2C9), omeprazole (CYP2C19), metoprolol (CYP2D6), and midazolam (CYP3A4). | Drug | High dose Gegen |
Primary outcome
Change in CYP1A2 phenotypic activity
Time frame: Session I (baseline) and Session II (after 14 days of Gegen administration); within each session, blood samples were collected at pre-dose (0 hour) and 0.25, 0.5, 0.75, 1, 2, 3, 4, 6, 8, 12, 24, 48, and 72 hours after dosing of cocktail probe drugs.
Plasma concentrations of caffeine and its metabolite paraxanthine were quantified by validated LC-MS/MS. CYP1A2 activity was expressed as the AUC0-t derived metabolite-to-parent ratio (unit of measure: ratio).
Change in CYP2B6 phenotypic activity
Time frame: Session I (baseline) and Session II (after 14 days of Gegen administration); within each session, blood samples were collected at pre-dose (0 hour) and 0.25, 0.5, 0.75, 1, 2, 3, 4, 6, 8, 12, 24, 48, and 72 hours after dosing of cocktail probe drugs.
Plasma concentrations of efavirenz and its metabolite 8-Hydroxy-efavirenz were quantified by validated LC-MS/MS. CYP1A2 activity was expressed as the AUC0-t derived metabolite-to-parent ratio (unit of measure: ratio).
Change in CYP2C9 phenotypic activity
Time frame: Session I (baseline) and Session II (after 14 days of Gegen administration); within each session, blood samples were collected at pre-dose (0 hour) and 0.25, 0.5, 0.75, 1, 2, 3, 4, 6, 8, 12, 24, 48, and 72 hours after dosing of cocktail probe drugs.
Plasma concentrations of losartan and its metabolite E-3174 were quantified by validated LC-MS/MS. CYP1A2 activity was expressed as the AUC0-t derived metabolite-to-parent ratio (unit of measure: ratio).
Change in CYP2C19 phenotypic activity
Time frame: Session I (baseline) and Session II (after 14 days of Gegen administration); within each session, blood samples were collected at pre-dose (0 hour) and 0.25, 0.5, 0.75, 1, 2, 3, 4, 6, 8, 12, 24, 48, and 72 hours after dosing of cocktail probe drugs.
Plasma concentrations of omeprazole and its metabolite 5-Hydroxy-omeprazole were quantified by validated LC-MS/MS. CYP1A2 activity was expressed as the AUC0-t derived metabolite-to-parent ratio (unit of measure: ratio).
Change in CYP2D6 phenotypic activity
Time frame: Session I (baseline) and Session II (after 14 days of Gegen administration); within each session, blood samples were collected at pre-dose (0 hour) and 0.25, 0.5, 0.75, 1, 2, 3, 4, 6, 8, 12, 24, 48, and 72 hours after dosing of cocktail probe drugs.
Plasma concentrations of metoprolol and its metabolite α-Hydroxy-metoprolol were quantified by validated LC-MS/MS. CYP1A2 activity was expressed as the AUC0-t derived metabolite-to-parent ratio (unit of measure: ratio).
Change in CYP3A4 phenotypic activity
Time frame: Session I (baseline) and Session II (after 14 days of Gegen administration); within each session, blood samples were collected at pre-dose (0 hour) and 0.25, 0.5, 0.75, 1, 2, 3, 4, 6, 8, 12, 24, 48, and 72 hours after dosing of cocktail probe drugs.
Plasma concentrations of midazolam and its metabolite 1'-Hydroxy-midazolam were quantified by validated LC-MS/MS. CYP1A2 activity was expressed as the AUC0-t derived metabolite-to-parent ratio (unit of measure: ratio).
Change in thromboxane B2 concentration
Time frame: Blood samples collected at pre-dose (0 hour) in Session I (baseline) and 72 hours post-cocktail-dose in Session II (after 14 days of Gegen dosing)
Plasma concentration of thromboxane B2, a biomarker of platelet activation and coagulation, was quantified by enzyme-linked immunosorbent assay (unit of measure: ng/mL).
Change in soluble thrombomodulin concentration
Time frame: Blood samples collected at pre-dose (0 hour) in Session I (baseline) and 72 hours post-cocktail-dose in Session II (after 14 days of Gegen dosing)
Plasma concentration of soluble thrombomodulin, a biomarker of endothelial function, was quantified by enzyme-linked immunosorbent assay (unit of measure: ng/mL).
Change in prothrombin time
Time frame: Blood samples collected at pre-dose (0 hour) in Session I (baseline) and 72 hours post-cocktail-dose in Session II (after 14 days of Gegen dosing)
Plasma prothrombin time, a coagulation parameter, was measured by standard clotting assay on an automated coagulometer (unit of measure: seconds).
1 secondary outcome
Incidence of adverse events
Time frame: From enrolment until the final visit (72 hours after the Session II probe cocktail administration)
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 5 Oct 2026.
- Individual participant dataSharing planned: No. Dataset includes identifiable genotype information.
Related trials for Herb-drug Interactions
RecruitingObservational study
Developing a Methodological Framework and a Dissemination Plan for Herb-drug Interactions-related Clinical Practice Guidelines
Herb-drug Interactions
Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Zhong Zuo, PhD principal investigator
Chinese University of Hong Kong
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 1 study testing Arm 1: Radix Puerariae lobatae (Gegen), Arm 1: Six-probe drug cocktail and Arm 2: Radix Puerariae lobatae (Gegen) in people with Herb-drug Interactions, run by Chinese University of Hong Kong at 1 site in Hong Kong.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 8 inclusion and 15 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 5 Oct 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Hong Kong. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 1 studies test a treatment in a small group of people for the first time or in a new way, mainly to check safety and find the right dose.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Change in CYP1A2 phenotypic activity (time frame: Session I (baseline) and Session II (after 14 days of Gegen administration); within each session, blood samples were collected at pre-dose (0 hour) and 0.25, 0.5, 0.75, 1, 2, 3, 4, 6, 8, 12, 24, 48, and 72 hours after dosing of cocktail probe drugs.). The study lists 9 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 5 Oct 2026.