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Bariatric Sleeve GastrectomyNCT07253805

Plasma and Tissue Concentration of Cefazolin in Preoperative Prophylaxis in Patients Undergoing Bariatric Surgery

An observational study of Bariatric Sleeve Gastrectomy and Cefazolin, run by Laval University at 1 site in Canada.

Active, not recruiting

Under way, not looking for participants. Everyone needed has enrolled. The study is still running.

Official record
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Trial summary

This study investigates whether current cefazolin dosing guidelines for obese patients-2 g IV for those <120 kg and 3 g IV for those ≥120 kg-achieve adequate plasma and tissue concentrations (≥8 mg/L) for effective surgical prophylaxis. Read more about this study

Who is it for?
Ages 18 years and older
Conditions the study is for
Bariatric Sleeve Gastrectomy, Cefazolin
How many people
70 participants
Where
1 siteCanada
Study dates
11 Apr 2019to 1 Feb 2026
Phase
Observational
Are there results?
Not yet: the study is under way

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

  • Ages 18 years and older
  • All sexes
  • No healthy volunteers
  • Adult, Older adult

Study population: All adults undergoing bariatric surgery.

Who may be able to join

  • Have a BMI ≥ 35 kg/m²
  • Undergo bariatric surgery (sleeve gastrectomy) via laparoscopy

Who cannot join

  • Under 18 years of age
  • Weight over 180 kg
  • Penicillin allergy
  • Pregnant or breastfeeding women
  • Chronic kidney disease (eGFR < 60 ml/min according to the Cockcroft-Gault equation)
  • Liver cirrhosis
  • Intraoperative blood loss ≥ 1 liter

Trial locations and contacts

1 site in 1 country.

Canada1 site

  • Institut universitaire de cardiologie et de pneumologie de Québec - Université Laval

    Québec, Quebec, G1V 4G5

Other trials in Canada

About this study

This study investigates whether current cefazolin dosing guidelines for obese patients-2 g IV for those <120 kg and 3 g IV for those ≥120 kg-achieve adequate plasma and tissue concentrations (≥8 mg/L) for effective surgical prophylaxis. While several retrospective and prospective studies suggest that a 2 g dose may be sufficient regardless of weight, findings are inconsistent and often rely solely on plasma concentrations. Given that tissue concentration at the site of action is a more relevant pharmacokinetic marker, the study emphasizes the need to measure cefazolin levels in adipose tissue. Previous research using microdialysis has shown reduced tissue distribution in obese patients, potentially warranting higher doses. The study also highlights variability in defining the minimum inhibitory concentration (MIC) required for prophylaxis, noting that 8 mg/L is often considered the threshold for Enterobacteriaceae. Ultimately, the study aims to clarify whether current dosing achieves effective antibiotic levels across different weight categories, with a focus on tissue concentrations.

Keywords
Cefazolin, Ancef, Bariatric surgery, Sleeve, gastrectomy

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

Study groups in NCT07253805
Study groupRoleWhat they receive
Clindamycin group/controlA control group of 10 patients undergoing sleeve gastrectomy at the Quebec Heart and Lung Institute, who have not been exposed to cefazolin due to penicillin allergy, will be recruited to validate the analytical method. During surgery, biopsies of adipose and dermal tissue and blood samples will be collected. No other antibiotic or medications will be administered to these patients.
Ancef groupSixty patients will be recruited for the study, with 20 patients assigned to each weight category. Recruitment will take place during the preoperative consultation at the bariatric surgery clinic. All patients expressing interest will be included, provided they do not meet any exclusion criteria (convenience sampling). During surgery, biopsies of adipose and dermal tissue and blood samples, will be collected. No additional antibiotics or medications will be administered to these patients.

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Area Under the Concentration-Time Curve (AUC) of Cefazolin in Plasma, Adipose Tissue, and Dermal Tissue

    AUC of cefazolin will be measured in plasma, adipose tissue, and dermal tissue at 0 minutes, 30 minutes, and at the end of surgery following administration according to current dosing guidelines.

    Unit of Measure:

    mg·min/L

    Measured: During surgery

Secondary outcomes (5)

  1. Proportion of Patients Achieving Cefazolin Tissue Concentrations ≥ 8 mg/L

    Proportion of patients with adipose and dermal tissue concentrations of cefazolin ≥ 8 mg/L at any time point (0 min, 30 min, end of surgery), based on the MIC for Enterobacteriaceae.

    Unit of Measure:

    Percentage of patients (%)

    Measured: During surgery

  2. Proportion of Patients Achieving Cefazolin Plasma Concentrations ≥ 2 mg/L

    Proportion of patients with plasma concentrations of cefazolin ≥ 2 mg/L at each time point (0 min, 30 min, end of surgery), based on the MIC for methicillin-sensitive Staphylococcus aureus (MSSA).

    Unit of Measure:

    Percentage of patients (%)

    Measured: During surgery

  3. Comparison of Cefazolin Concentrations Across Weight Categories

    Comparison of plasma and tissue concentrations of cefazolin across weight categories (<120 kg, 120-149 kg, ≥150 kg) to identify potential underexposure in higher weight groups.

    Unit of Measure:

    Mean concentration (mg/L)

    Measured: During surgery

  4. Tissue-to-Plasma Concentration Ratio of Cefazolin

    Ratio of cefazolin concentration in tissue to plasma at each time point to assess distribution efficiency.

    Unit of Measure:

    Ratio (unitless)

    Measured: During surgery

  5. Time Above MIC (T>MIC) for Cefazolin in Plasma and Tissue

    Duration (in minutes) that cefazolin concentrations remain above MIC in plasma and tissue compartments, if additional time points are available.

    Unit of Measure:

    Minutes

    Measured: During surgery

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted28 Nov 2025
  2. Study start11 Apr 2019
  3. Primary completion16 Feb 2022
  4. Study completion1 Feb 2026 (estimated)

Resources

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design
Study type
Observational
Observational model
Cohort
Time perspective
Prospective
Enrolment
70 participants (actual)
IDs, dates and publications
ClinicalTrials.gov ID
NCT07253805
Sponsor's protocol ID
CER 21626, 2019-3053
Status last verified
Nov 2025
First submitted
13 Nov 2025
Last updated
28 Nov 2025
Results posted
No
Data monitoring committee
No
FDA-regulated drug
No
FDA-regulated device
No
Individual data sharing
No: Not applicable for this study

Publications

  • Flegal KM, Kruszon-Moran D, Carroll MD, Fryar CD, Ogden CL. Trends in Obesity Among Adults in the United States, 2005 to 2014. JAMA. 2016 Jun 7;315(21):2284-91. doi: 10.1001/jama.2016.6458.

    PubMed 27272580

  • Nicoli S, Santi P. Assay of amikacin in the skin by high-performance liquid chromatography. J Pharm Biomed Anal. 2006 Jun 7;41(3):994-7. doi: 10.1016/j.jpba.2005.12.029. Epub 2006 Feb 8.

    PubMed 16466885

  • Signs SA, File TM, Tan JS. High-pressure liquid chromatographic method for analysis of cephalosporins. Antimicrob Agents Chemother. 1984 Nov;26(5):652-5. doi: 10.1128/AAC.26.5.652.

    PubMed 6517553

  • Waltrip T, Lewis R, Young V, Farmer M, Clayton S, Myers S, Gray LA Jr, Galandiuk S. A pilot study to determine the feasibility of continuous cefazolin infusion. Surg Infect (Larchmt). 2002 Spring;3(1):5-9. doi: 10.1089/109629602753681104.

    PubMed 12593694

  • Chen X, Brathwaite CE, Barkan A, Hall K, Chu G, Cherasard P, Wang S, Nicolau DP, Islam S, Cunha BA. Optimal Cefazolin Prophylactic Dosing for Bariatric Surgery: No Need for Higher Doses or Intraoperative Redosing. Obes Surg. 2017 Mar;27(3):626-629. doi: 10.1007/s11695-016-2331-9.

    PubMed 27520693

  • Liu P, Muller M, Derendorf H. Rational dosing of antibiotics: the use of plasma concentrations versus tissue concentrations. Int J Antimicrob Agents. 2002 Apr;19(4):285-90. doi: 10.1016/s0924-8579(02)00024-9.

    PubMed 11978499

  • Hites M, Deprez G, Wolff F, Ickx B, Verleije A, Closset J, Loi P, Prevost J, Taccone FS, Racape J, Cotton F, Jacobs F. Evaluation of total body weight and body mass index cut-offs for increased cefazolin dose for surgical prophylaxis. Int J Antimicrob Agents. 2016 Dec;48(6):633-640. doi: 10.1016/j.ijantimicag.2016.08.019. Epub 2016 Oct 5.

    PubMed 28128093

  • van Kralingen S, Taks M, Diepstraten J, van de Garde EM, van Dongen EP, Wiezer MJ, van Ramshorst B, Vlaminckx B, Deneer VH, Knibbe CA. Pharmacokinetics and protein binding of cefazolin in morbidly obese patients. Eur J Clin Pharmacol. 2011 Oct;67(10):985-92. doi: 10.1007/s00228-011-1048-x. Epub 2011 Apr 16.

    PubMed 21499760

  • Ho VP, Nicolau DP, Dakin GF, Pomp A, Rich BS, Towe CW, Barie PS. Cefazolin dosing for surgical prophylaxis in morbidly obese patients. Surg Infect (Larchmt). 2012 Feb;13(1):33-7. doi: 10.1089/sur.2010.097. Epub 2012 Feb 8.

    PubMed 22316145

  • Unger NR, Stein BJ. Effectiveness of pre-operative cefazolin in obese patients. Surg Infect (Larchmt). 2014 Aug;15(4):412-6. doi: 10.1089/sur.2012.167. Epub 2014 May 13.

    PubMed 24824510

  • Pories WJ, van Rij AM, Burlingham BT, Fulghum RS, Meelheim D. Prophylactic cefazolin in gastric bypass surgery. Surgery. 1981 Aug;90(2):426-32.

    PubMed 7020141

  • Bratzler DW, Dellinger EP, Olsen KM, Perl TM, Auwaerter PG, Bolon MK, Fish DN, Napolitano LM, Sawyer RG, Slain D, Steinberg JP, Weinstein RA; American Society of Health-System Pharmacists; Infectious Disease Society of America; Surgical Infection Society; Society for Healthcare Epidemiology of America. Clinical practice guidelines for antimicrobial prophylaxis in surgery. Am J Health Syst Pharm. 2013 Feb 1;70(3):195-283. doi: 10.2146/ajhp120568. No abstract available.

    PubMed 23327981

  • Shabanzadeh DM, Sorensen LT. Laparoscopic surgery compared with open surgery decreases surgical site infection in obese patients: a systematic review and meta-analysis. Ann Surg. 2012 Dec;256(6):934-45. doi: 10.1097/SLA.0b013e318269a46b.

    PubMed 23108128

  • Peppard WJ, Eberle DG, Kugler NW, Mabrey DM, Weigelt JA. Association between Pre-Operative Cefazolin Dose and Surgical Site Infection in Obese Patients. Surg Infect (Larchmt). 2017 May/Jun;18(4):485-490. doi: 10.1089/sur.2016.182. Epub 2016 Dec 1.

    PubMed 27906601

  • Chopra T, Zhao JJ, Alangaden G, Wood MH, Kaye KS. Preventing surgical site infections after bariatric surgery: value of perioperative antibiotic regimens. Expert Rev Pharmacoecon Outcomes Res. 2010 Jun;10(3):317-28. doi: 10.1586/erp.10.26.

    PubMed 20545596

Questions about this trial

What is this clinical trial studying?

An observational study of Bariatric Sleeve Gastrectomy and Cefazolin, run by Laval University at 1 site in Canada.

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 2 inclusion and 7 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: under way, not looking for participants, as of the sponsor's last update on 28 Nov 2025. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 1 site in Canada. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

Are results available for this study?

This study is still under way. Results are not available in the source record yet.

How can a doctor refer a patient or contact the research team?

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Area Under the Concentration-Time Curve (AUC) of Cefazolin in Plasma, Adipose Tissue, and Dermal Tissue (time frame: During surgery). It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT07253805, which also lists 21 linked publications.

Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 28 Nov 2025.

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