Effect of Weight and/or Obesity on Sulfamethoxazole and Trimethoprim Concentrations

This study has been completed.
National Center for Research Resources (NCRR)
University of Texas Southwestern Medical Center
Information provided by (Responsible Party):
Ron Hall, Texas Tech University Health Sciences Center
ClinicalTrials.gov Identifier:
First received: July 20, 2010
Last updated: June 9, 2014
Last verified: June 2014

This study will find how weight affects the dosing of a drug called sulfamethoxazole and trimethoprim. Currently, the amount of sulfamethoxazole and trimethoprim a patient receives is the same regardless of the patient's weight.

All sulfamethoxazole and trimethoprim (Trade name is Bactrim or Septra) medication that you will receive in this study will be referred to as study medication within this informed consent form. This drug is a combination of two antibiotics, sulfamethoxazole and trimethoprim, which belongs to a class of medication known as "sulfones" and is approved by the US Food and Drug Administration (FDA) for the treatment of a wide variety of bacterial infections such as ear infections, urinary tract infections, bronchitis, traveler's diarrhea, and Pneumocystis carinii pneumonia. Sulfamethoxazole and trimethoprim is given orally.

Condition Intervention Phase
Drug: Sulfamethoxazole/trimethoprim
Phase 4

Study Type: Interventional
Study Design: Endpoint Classification: Pharmacokinetics/Dynamics Study
Intervention Model: Single Group Assignment
Masking: Open Label
Primary Purpose: Treatment
Official Title: Population Pharmacokinetic Analysis of Sulfamethoxazole and Trimethoprim in Normal Weight, Overweight, and Obese Volunteers

Resource links provided by NLM:

Further study details as provided by Texas Tech University Health Sciences Center:

Primary Outcome Measures:
  • Serum clearance [ Time Frame: 24 hours ] [ Designated as safety issue: No ]
    Blood draws will be conducted over 24 hours to determine the serum clearance of trimethoprim and sulfamethoxazole.

Enrollment: 36
Study Start Date: July 2010
Study Completion Date: May 2012
Primary Completion Date: May 2012 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Experimental: Sulfamethoxazole/trimethoprim
2 DS tablets of sulfamehtoxazole/trimethoprim (1600 mg/320 mg)
Drug: Sulfamethoxazole/trimethoprim
2 DS tablets of trimethoprim/sulfamethoxazole x 1 dose


Ages Eligible for Study:   18 Years and older
Genders Eligible for Study:   Both
Accepts Healthy Volunteers:   Yes

Inclusion Criteria:

  • Male and female subjects, age >18 years, of all racial and ethnic origins.
  • We are recruiting 12 normal or underweight (BMI <25kg/m2), 12 overweight or obese (BMI 25-40 kg/m2), and 12 extremely obese (BMI > 40 kg/m2) for this study. This index is calculated using the volunteer's height and weight (Formula: weight (lb) / [height (in)]2 x 703). Half of each group will be male; the other half will be female.

Exclusion Criteria:

  • Pregnant or nursing or unwilling to use a reliable contraception method during the study. The effects of sulfamethoxazole and trimethoprim on pregnancy are unknown. In addition, the metabolic changes that accompany pregnancy may alter the concentration-time profile of sulfamethoxazole and trimethoprim, so that the pregnancy and post-partum state would be a confounding variable.
  • Abnormal liver function tests: transaminases>10 times upper limit of normal, Alkaline phosphatase>5 times upper limit of normal, total bilirubin>5 times upper limit of normal.
  • History of allergies to sulfones, sulfonamides or trimethoprim.
  • Sulfones, sulfonamides or trimethoprim are contraindicated for any reason.
  • Volunteers unwilling to comply with study procedures.
  • Current suspected or documented ear infection, urinary tract infection, bronchitis, traveler's diarrhea, Pneumocystis carinii pneumonia, or any other bacterial infection.
  • Volunteers with colon resection, gastric bypass, lap band, or any other conditions inhibiting gastric absorption of drug.
  • Current or previous participation within 28 days of enrollment in another research study that involves the use of medication, contrast, or any other compound that may alter blood count and/or blood chemistry (liver function, kidney function or electrolyte balance), unless waved by PI.
  • Donation of 450mL (one unit) of blood or more within 8 weeks (56 days) prior to study enrollment, unless waved by PI.
  • Current use of medications contraindication with sulfamethoxazole/trimethoprim use: Bepridil, Cisapride, Dofetilide, Levomethadyl, Mesoridazine, Pimozide, Terfenadine, and Thioridazine. Other medications will be screened by study investigators to ensure the safety of research participants and maintain the quality of the study.
  Contacts and Locations
Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below. For general information, see Learn About Clinical Studies.

Please refer to this study by its ClinicalTrials.gov identifier: NCT01167452

United States, Texas
University of Texas Southwestern Medical Center
Dallas, Texas, United States, 75390
Sponsors and Collaborators
Texas Tech University Health Sciences Center
National Center for Research Resources (NCRR)
University of Texas Southwestern Medical Center
Principal Investigator: Ronald Hall, PharmD, MSCS Texas Tech UHSC
  More Information

Responsible Party: Ron Hall, Associate Professor, Texas Tech University Health Sciences Center
ClinicalTrials.gov Identifier: NCT01167452     History of Changes
Other Study ID Numbers: AMA IRB A10-3592  5UL1RR024982-02 
Study First Received: July 20, 2010
Last Updated: June 9, 2014
Health Authority: United States: Institutional Review Board

Keywords provided by Texas Tech University Health Sciences Center:

Additional relevant MeSH terms:
Actinomycetales Infections
Bacterial Infections
Body Weight
Gram-Positive Bacterial Infections
Mycobacterium Infections
Nutrition Disorders
Signs and Symptoms
Trimethoprim, Sulfamethoxazole Drug Combination
Anti-Bacterial Agents
Anti-Infective Agents
Anti-Infective Agents, Urinary
Antiparasitic Agents
Antiprotozoal Agents
Cytochrome P-450 CYP2C8 Inhibitors
Cytochrome P-450 Enzyme Inhibitors
Enzyme Inhibitors
Folic Acid Antagonists
Molecular Mechanisms of Pharmacological Action
Renal Agents

ClinicalTrials.gov processed this record on May 26, 2016