Drug Metabolizing Enzyme and Transporter Function in Chronic Kidney Disease
Chronic Kidney Diseases, Deficiency, Vitamin D
About this trial
This is an interventional other trial for Chronic Kidney Diseases
Eligibility Criteria
Inclusion criteria for CKD patients:
- vitamin D deficient (<30 ng/mL)
- hemoglobin >10 g/dL
- willing to abstain from fruit juices or alcohol within 7 days of PK assessments
- no changes in prescription or nonprescription medications within 4 wks of study start
- age 18-70 yrs
- If a diagnosis of CKD, must be due to diabetes mellitus or hypertension
- Signed informed consent
Inclusion Criteria for Healthy Controls:
- vitamin D deficient (<30 ng/mL)
- hemoglobin >10 g/dL
- willing to abstain from fruit juices or alcohol within 7 days of PK assessments
- no changes in prescription or nonprescription medications within 4 wks of study start
- age 18-70 yrs
- Signed informed consent
Exclusion criteria for CKD patients:
- History of >14 alcoholic drinks/wk
- Not likely to be compliant with study visits
- Pregnant or lactating
- Predisposition to or history of hypercalcemia
- History of allergy, sensitivity, or contraindication to probe drugs (seizures, drug metabolism interactions, etc)
- Use of prescribed or nonprescribed therapies that could interact with probe drugs (including prototypical inhibitors or inducers)
- Active autoimmune disease or active/recent infections requiring antimicrobial treatment within the previous 4 wks will be excluded to minimize inflammatory-mediated changes in vitamin D status and patient heterogeneity.
- Presence of clinically significant hepatic insufficiency (total bilirubin greater than 1.5 times the upper limit of normal or transaminase (ALT, AST) elevations greater than 2 times the upper limit of the laboratory reference range or liver disease
- Active seizure disorder or those patients receiving large doses of medications that are known to reduce seizure threshold
- Currently receiving cholecalciferol or a vitamin D analogue
Exclusion Criteria for Healthy Controls:
- History of >14 alcoholic drinks/wk
- Not likely to be compliant with study visits
- Pregnant or lactating
- Predisposition to or history of hypercalcemia
- History of allergy, sensitivity, or contraindication to probe drugs (seizures, drug metabolism interactions, etc)
- Use of prescribed or nonprescribed therapies that could interact with probe drugs (including prototypical inhibitors or inducers)
- Active autoimmune disease or active/recent infections requiring antimicrobial treatment within the previous 4 wks will be excluded to minimize inflammatory-mediated changes in vitamin D status and patient heterogeneity.
- Presence of clinically significant hepatic insufficiency (total bilirubin greater than 1.5 times the upper limit of normal or transaminase (ALT, AST) elevations greater than 2 times the upper limit of the laboratory reference range or liver disease
- Active seizure disorder or those patients receiving large doses of medications that are known to reduce seizure threshold
- Currently receiving cholecalciferol or a vitamin D analogue
- Any clinical evidence of chronic kidney disease as defined by the National Kidney Foundation Dialysis Outcomes Quality Initiative (NKF DOQI) guidelines
Sites / Locations
- University of Colorado
- University of Pittsburgh
Arms of the Study
Arm 1
Arm 2
Experimental
Experimental
Arm 1: Drug Metabolism and Transport
Arm 2: Vitamin D Pharmacokinetics
The aim of Arm 1 is to determine the effect of vitamin D deficiency and repletion on xenobiotic clearance in vivo. The study will evaluate the in vivo function of targeted metabolism and transport pathways in 40 CKD and 18 healthy volunteer subjects (controls) under the influence of a vitamin D depleted state and repeated under a vitamin D replete state with cholecalciferol. The function of two major phase I drug metabolizing enzymes (CYP2B6, CYP3A), and three transporters [P-gp, MRP2, and MATE1/2K] will be assessed by administering oral bupropion, midazolam, olmesartan, and fexofenadine.
The aim of Arm 2 is to determine the effect of CKD on the in vivo function of individual CYP450s responsible for vitamin D metabolism and their functional relevance on the pharmacokinetics of cholecalciferol. A total of 90 CKD subjects will be enrolled [30 per group: group I (CKD stage 1/2), group II (CKD stage 3), and group III (CKD stage 4/5, pre-ESRD)], as well as 30 healthy controls.