Cannabidiol (CBD) is available as a prescription drug product for the treatment of seizures associated with Lennox-Gastaut syndrome, Dravet syndrome, or tuberous sclerosis complex. At labeled doses up to 25 mg/kg/day, an increased risk of liver enzyme elevation and drug-induced liver injury has been observed. However, only limited evaluations of the risk of liver enzyme elevation of daily, lower dose CBD use are available. The potential for liver enzyme elevations with lower CBD doses with unapproved consumer products highlights a need for further research. In addition, CBD has the capacity to inhibit cytochrome P450 enzymes and uridine 5'-diphospho-glucuronosyltransferases, leading to potential drug-drug interactions with multiple common medications. The clinical significance of many of these interactions is also unclear. Furthermore, nonclinical studies have suggested the potential for CBD to cause reproductive and endocrine effects. As such, additional high-quality clinical pharmacology studies are needed to further characterize CBD's safety profile. The objective of this study is to characterize the effects of daily CBD use at a dose within the range of what consumers are taking as unapproved CBD products on liver enzyme elevations, drug interactions, and endocrine measures.
The cannabis plant contains bioactive compounds known as cannabinoids; delta-9 tetrahydrocannabinol (THC) and cannabidiol (CBD) are the most prevalent cannabinoids in most varieties of cannabis. The Agricultural Improvement Act (Farm Bill) of 2018 removed hemp, defined as cannabis and derivatives of cannabis with extremely low concentrations of THC, from the definition of marijuana in the Controlled Substances Act. Following this, many CBD products have been made available to consumers. However, hemp products remain subject to regulation under the Federal Food Drug \& Cosmetic Act, when applicable (e.g., as drugs, foods, dietary supplements, cosmetics, veterinary products) and the growing CBD products market raises various safety concerns, especially with long-term use. CBD is available as a prescription drug product for the treatment of seizures associated with Lennox-Gastaut syndrome, Dravet syndrome, or tuberous sclerosis complex. At labeled doses up to 25 mg/kg/day, an increased risk of liver enzyme elevation and drug-induced liver injury has been observed. However, only limited evaluations of the risk of liver enzyme elevation of daily, lower dose CBD use are available. The potential for liver enzyme elevations with CBD doses in unapproved consumer products highlights a need for further research to quantify risks at these doses. In addition, CBD has the capacity to inhibit cytochrome P450 enzymes and uridine 5'-diphospho-glucuronosyltransferases, leading to potential drug-drug interactions with multiple common medications. The clinical significance of many of these interactions is also unclear. Furthermore, nonclinical studies have suggested the potential for CBD to cause reproductive and endocrine effects. As such, additional high-quality clinical pharmacology studies are needed to further characterize CBD's safety profile. This study will be divided into two parts. In Part 1, 200 healthy subjects will be randomized to 5 mg/kg/day of CBD (150 subjects) or placebo (50 subjects) for 4 weeks with weekly laboratory assessments to characterize the percentage of participants with liver enzyme elevation (primary endpoint) or meeting withdrawal criteria for potential drug-induced liver injury (secondary endpoint). Additional secondary endpoints include the change from baseline after 4 weeks of daily CBD dosing for male reproductive (testosterone and inhibin B) and thyroid hormones (thyroid stimulating hormone \[TSH\], triiodothyronine \[T3\] and thyroxine \[T4\]) as secondary endpoints. Exploratory endpoints include additional characterization of liver findings and other blood biomarkers. In Part 2, 40 healthy subjects will receive either oral citalopram (20 subjects) or morphine (20 subjects) at baseline and then again after receiving CBD 5 mg/kg/day to characterize the effect of daily cannabidiol use on the plasma concentration of citalopram and morphine. Citalopram was selected because it is a common prescription medication for depression and anxiety that is metabolized by CYP2C19 and CYP3A4, which CBD inhibits. Morphine was selected because it is a common opioid analgesic that is metabolized by UGT2B7, which CBD inhibits.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
OTHER
Masking
QUADRUPLE
Enrollment
241
Cannabidiol (Epidiolex) will be administered orally 2.5 mg/kg twice daily (5 mg/kg/day) for 28 days in Part 1 and for 9 days (morphine cohort) or 12 days (citalopram cohort) in Part 2.
Placebo will be administered orally twice daily for 28 days in Part 1
Citalopram (Celexa) will be administered once at 20 mg on days 1 and 13.
Morphine will be administered once at 15 mg on days 1, 4, and 11.
Spaulding Clinical Research
West Bend, Wisconsin, United States
Part 1 - Percentage of Participants With an Alanine Transaminase (ALT) or Aspartate Aminotransferase (AST) Liver Enzyme Elevation Greater Than Three Times the Upper Limit of Normal (> 3 × ULN).
The upper limit of normal (ULN), based on consensus criteria, for the liver transaminase ALT (Alanine transaminase) is defined as 33 U/L for males and 25 U/L for females. An ALT evaluation three times the ULN for males would be 99 U/L and 75 U/L for females.
Time frame: Days 1 through 35
Part 2 - Area Under the Plasma Concentration-time Curve (AUC) of Citalopram When Administered Alone Versus When Co-administered With Cannabidiol After 7 Days of CBD Dosing.
AUC will be determined by collecting pharmacokinetic (PK) blood samples and calculated using noncompartmental analysis. 13 PK samples will be obtained with each citalopram dose for a total number of 26 PK samples per citalopram cohort participant. The outcome measure reported will be the geometric mean ratio for citalopram alone compared to citalopram after 7 days of CBD dosing.
Time frame: 0, 1, 2, 3, 4, 6, 8, 12, 24, 48, 72, 96, and 120 hours after each citalopram dose (Days 1 and 13)
Part 2 - Maximum Concentration (Cmax) of Citalopram When Administered Alone Versus When Co-administered With CBD After 7 Days of Cannabidiol Dosing.
Cmax will be determined by collecting pharmacokinetic (PK) blood samples and calculated using noncompartmental analysis. 13 PK samples will be obtained with each citalopram dose for a total number of 26 PK samples per citalopram cohort participant. The outcome measure reported will be the geometric mean ratio for citalopram alone compared to citalopram after 7 days of CBD dosing.
Time frame: 0, 1, 2, 3, 4, 6, 8, 12, 24, 48, 72, 96, and 120 hours after each citalopram dose (Days 1 and 13)
Part 2 - Morphine AUC When Administered Alone Versus When Co-administered With the First Dose of Cannabidiol and After 7 Days of CBD Dosing.
AUC will be determined by collecting pharmacokinetic (PK) blood samples and calculated using noncompartmental analysis.13 PK samples will be obtained with each morphine dose for a total number of 39 PK samples per morphine cohort participant. The outcome measure reported will be the geometric mean ratio for morphine alone compared to morphine after 7 days of CBD dosing.
Time frame: 0, 0.25, 0.5, 0.75, 1, 1.5, 2, 3, 4, 6, 12, 24, and 48 hours after each morphine dose (Days 1, 4, and 11)
Part 2 - Morphine Cmax When Administered Alone Versus When Co-administered With the First Dose of Cannabidiol and After 7 Days of Cannabidiol Dosing.
Cmax will be determined by collecting pharmacokinetic (PK) blood samples and calculated using noncompartmental analysis.13 PK samples will be obtained with each morphine dose for a total number of 39 PK samples per morphine cohort participant. The outcome measure reported will be the geometric mean ratio for morphine alone compared to morphine after 7 days of CBD dosing.
Time frame: 0, 0.25, 0.5, 0.75, 1, 1.5, 2, 3, 4, 6, 12, 24, and 48 hours after each morphine dose (Days 1, 4, and 11)
Part 1 - Percentage of Participants Meeting Withdrawal Criteria for Potential Drug-induced Liver Injury (DILI).
Withdrawal criteria for potential drug-induced liver-injury: laboratory results meeting any of the following criteria. * ALT or AST \> 3 x ULN (ULN for ALT is 33 U/L for males and 25 U/L for females) with the appearance of fatigue, nausea, vomiting, right upper quadrant pain or tenderness, fever, rash, and/or eosinophilia (\> 5%) OR * ALT elevation ≥ 5 × ULN (ULN for ALT is 33 U/L for males and 25 U/L for females) OR * Alkaline phosphatase (ALP) elevation ≥ 2 × ULN (with accompanying elevations of gamma-glutamyl transpeptidase (GGT) in the absence of known bone pathology driving the rise in ALP level) OR * ALT elevation ≥ 3 × ULN and bilirubin concentration \> 2 × ULN
Time frame: Days 1 through 35
Part 1 - Change From Baseline in Total Testosterone in Male Participants After Cannabidiol Administration Compared to Placebo.
Endocrine assessments for total testosterone will be obtained through blood samples. A linear mixed effect model will be utilized to obtain least squares means for each treatment group.
Time frame: Days 1 and 29
Part 1 - Change From Baseline in Inhibin B in Male Participants After Cannabidiol Administration Compared to Placebo.
Endocrine assessments for inhibin B will be obtained through blood samples. A linear mixed effect model will be utilized to obtain least squares means for each treatment group.
Time frame: Days 1 and 29
Part 1 - Change From Baseline in Thyroid Stimulating Hormone (TSH) After Cannabidiol Administration Compared to Placebo.
Endocrine assessments for TSH will be obtained through blood samples. A linear mixed effect model will be utilized to obtain least squares means for each treatment group.
Time frame: Days 1 and 29
Part 1 - Change From Baseline in Total T3 After Cannabidiol Administration Compared to Placebo.
Endocrine assessments for total T3 will be obtained through blood samples. A linear mixed effect model will be utilized to obtain least squares means for each treatment group.
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Time frame: Days 1 and 29
Part 1 - Change From Baseline in Free T4 After Cannabidiol Administration Compared to Placebo.
Endocrine assessments for free T4 will be obtained through blood samples. A linear mixed effect model will be utilized to obtain least squares means for each treatment group.
Time frame: Days 1 and 29
Part 2 - Morphine-3-glucuronide (M3G) AUC When Morphine is Administered Alone Versus When Co-administered With Cannabidiol.
AUC will be determined by collecting pharmacokinetic (PK) blood samples and calculated using noncompartmental analysis.13 PK samples will be obtained with each morphine dose for a total number of 39 PK samples per morphine cohort participant. The outcome measure reported will be the geometric mean ratio for morphine-3-glucuronide (M3G) alone compared to morphine-3-glucuronide (M3G) after 7 days of CBD dosing.
Time frame: 0, 0.25, 0.5, 0.75, 1, 1.5, 2, 3, 4, 6, 12, 24, and 48 hours after each morphine dose (Days 1, 4, and 11)
Part 2 - M3G Cmax When Morphine is Administered Alone Versus When Co-administered With Cannabidiol.
Cmax will be determined by collecting pharmacokinetic (PK) blood samples and calculated using noncompartmental analysis.13 PK samples will be obtained with each morphine dose for a total number of 39 PK samples per morphine cohort participant. The outcome measure reported will be the geometric mean ratio for morphine-3-glucuronide (M3G) alone compared to morphine-3-glucuronide (M3G) after 7 days of CBD dosing.
Time frame: 0, 0.25, 0.5, 0.75, 1, 1.5, 2, 3, 4, 6, 12, 24, and 48 hours after each morphine dose (Days 1, 4, and 11)
Part 2 - Morphine-6-glucuronide (M6G) AUC When Morphine is Administered Alone Versus When Co-administered With Cannabidiol.
AUC will be determined by collecting pharmacokinetic (PK) blood samples and calculated using noncompartmental analysis.13 PK samples will be obtained with each morphine dose for a total number of 39 PK samples per morphine cohort participant. The outcome measure reported will be the geometric mean ratio for morphine-6-glucuronide (M6G) alone compared to morphine-6-glucuronide (M6G) after 7 days of CBD dosing.
Time frame: 0, 0.25, 0.5, 0.75, 1, 1.5, 2, 3, 4, 6, 12, 24, and 48 hours after each morphine dose (Days 1, 4, and 11)
Part 2 - M6G Cmax When Morphine is Administered Alone Versus When Co-administered With Cannabidiol.
Cmax will be determined by collecting pharmacokinetic (PK) blood samples and calculated using noncompartmental analysis.13 PK samples will be obtained with each morphine dose for a total number of 39 PK samples per morphine cohort participant. The outcome measure reported will be the geometric mean ratio for morphine-6-glucuronide (M6G) alone compared to morphine-6-glucuronide (M6G) after 7 days of CBD dosing.
Time frame: 0, 0.25, 0.5, 0.75, 1, 1.5, 2, 3, 4, 6, 12, 24, and 48 hours after each morphine dose (Days 1, 4, and 11)