Effect of Weight and/or Obesity on Ethambutol Drug Concentrations

Texas Tech University Health Sciences Center18 enrolled

Overview

This study is designed to measure drug concentrations in the blood of healthy volunteers administered a single dose of ethambutol. Our hypothesis is that volunteers with a body mass index (BMI) 25-40 kg/m2 will remove ethambutol more quickly from the blood than leaner volunteers, and those with a BMI \> 40 kg/m2 will have even greater clearance than those who are leaner.

Study Type

INTERVENTIONAL

Allocation

Masking

NONE

Enrollment

Conditions

Obesity Tuberculosis

Interventions

EthambutolDRUG

All volunteers in each category will receive a single dose of oral ethambutol based on American Thoracic Society/Centers for Disease Control and Prevention/Infectious Diseases Society of American (ATS/CDC/IDSA) TB treatment guidelines.1 We will not use any doses higher than the maximum dose recommended for daily administration by the current ATS/CDC/IDSA TB guidelines (which use ideal body weight for dosing): 40-55kg: 800 mg (two 400 mg tablets) 56-75kg: 1,200 mg (three 400 mg tablets) 76-90kg: 1,600 mg (four 400 mg tablets) \> 90 kg: No dosage recommendations so these volunteers will only receive 1,600 mg (four 400 mg tablets)

Eligibility

Sex: ALLMin age: 18 YearsHealthy volunteers:

Medical Language ↔ Plain English

Inclusion Criteria: * Male and female volunteers, age 18 years of age or older, of all racial and ethnic origins. English and/or Spanish speaking volunteers are eligible to participate. * We are recruiting 6 normal weight (BMI \<25 kg/m2), 6 obese (BMI 25-40 kg/m2), and 6 extremely obese (BMI \> 40 kg/m2) for this study. Half of each group will be male, the other half will be female. Exclusion Criteria: * Creatinine clearance \< 70 ml/min as estimated by the Cockcroft-Gault equation. * Pregnant or nursing or unwilling to use a reliable contraception method during the study period. The effects of ethambutol on pregnancy are unknown. In addition, the metabolic changes that accompany pregnancy may alter the concentration-time profile of ethambutol, so that the pregnancy and post-partum state would be a confounding variable. * Abnormal liver function tests: transaminases \>10 time the upper limit of normal, alkaline phosphatase \> 5 time the upper limit of normal, total bilirubin \>5 time the upper limit of normal. * History of allergy to ethambutol. * Ethambutol is contraindicated for any reason. * Suspected or documented mycobacterial infection. * History of gout.

Locations (1)

University of Texas Southwestern Medical Center

Dallas, Texas, United States

Outcomes

Primary Outcomes

Total Clearance of Ethambutol

Time frame: Blood samples will be collected over a 24 hour period (0, 2, 6, 11, 18, and 24 hours)

Data from ClinicalTrials.gov

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