Hypothyroidism Primary
Conditions
Brief summary
This study was a prospective, single-center, open-label, non-randomized, pharmacokinetic study using stable isotope carbon-13 labeled levothyroxine
Detailed description
Setting The study was conducted on the clinical research unit of an academic medical center. Participants Adults of any age being treated with levothyroxine for hypothyroidism were studied. Interventions A single dose of 13C- LT4 was administered to hypothyroid subjects taking levothyroxine replacement. Main Outcomes and Measures Eighteen serial plasma samples were collected. One sample was obtained before the 13C- LT4 dose and the remainder over the 312-hour period post-dosing. 13C- LT4 concentration was quantified using validated liquid chromatography tandem mass spectrometry methods. Pharmacokinetic analysis was conducted using linear log trapezoidal non-compartmental analysis using Phoenix 6.4.
Interventions
DRUGAdministration of stable Isotope labeled levothyroxine
Administration of single dose of stable isotope carbon-13 labeled levothyroxine and measurement of blood levels of stable isotope-labeled levothyroxine
Sponsors
Georgetown University
Study design
Allocation
NA
Intervention model
SINGLE_GROUP
Primary purpose
OTHER
Masking
NONE
Intervention model description
Open label prospective study
Eligibility
Sex/Gender
ALL
Age
21 Years to No maximum
Healthy volunteers
No
Inclusion criteria
* age \>21 years at the time of consent * euthyroidism while undergoing treatment with LT4 * no other serious illness * ability to give written informed consent.
Exclusion criteria
* baseline hematocrit lower than 28.0% * TSH greater than 4.5 mIU/L * kidney dysfunction * concomitant use of drugs that affect thyroidal axis interactions
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| CL/F | 120 hours | oral clearance rate (defined as the ratio of dose administered to AUC0-∞) |
| V/F | 120 hours | apparent volume of distribution (estimated by CL/F/ λ) |
| t-half | 120 hours | the half-life of the terminal disposition phase (t-half) estimated by ln(2)/λ . |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| CL/F analysed by age groups | 120 hours | CL/F will be compared in adults (age ≤60 years) versus elderly (age\>60 years) using Wilcoxon signed-rank test using significance level of α = 0.05. Additionally, these PK parameters were regressed against age (as a continuous covariate). Sex (male or female), weight (as a continuous covariate), and body mass index (BMI) (as a continuous covariate) will be considered using a stepwise linear regression approach. |
| V/F analysed by age groups | 120 hours | V/F will be compared in adults (age ≤60 years) versus elderly (age\>60 years) using Wilcoxon signed-rank test using significance level of α = 0.05. Additionally, these PK parameters were regressed against age (as a continuous covariate). Sex (male or female), weight (as a continuous covariate), and body mass index (BMI) (as a continuous covariate) will be considered using a stepwise linear regression approach. |
| t-half by age groups | 120 hours | t-half will be compared in adults (age ≤60 years) versus elderly (age\>60 years) using Wilcoxon signed-rank test using significance level of α = 0.05. Additionally, these PK parameters were regressed against age (as a continuous covariate). Sex (male or female), weight (as a continuous covariate), and body mass index (BMI) (as a continuous covariate) will be considered using a stepwise linear regression approach. |
Outcome results
None listed