Study of Effectiveness and Safety of Azithromycin-based Extended-spectrum Prophylaxis to Prevent Post Cesarean Infection (C/SOAP)

This study has been completed.
University of Texas
University of North Carolina
Mission Hospital
Ochsner Health System
The University of Texas Health Science Center, Houston
Columbia University
University of Utah
University of Mississippi Medical Center
Information provided by (Responsible Party):
Alan Tita, University of Alabama at Birmingham Identifier:
First received: November 4, 2010
Last updated: May 21, 2015
Last verified: May 2015

The Cesarean Section Optimal Antibiotic Prophylaxis (C/SOAP) study is a large pragmatic multi-center randomized clinical trial designed to evaluate the comparative effectiveness and safety of azithromycin-based extended-spectrum antibiotic prophylaxis (azithromycin plus standard narrow-spectrum cephalosporin) relative to standard single-agent cephalosporin (preferably prior to surgical incision) to prevent post-cesarean infection.

Hypothesis: Compared to narrow-spectrum prophylaxis (i.e. cefazolin alone, or clindamycin if cephalosporin allergy) prior to surgical incision, the addition of extended-spectrum prophylaxis (azithromycin + cefazolin) reduces the incidence of post-cesarean infection.

Condition Intervention
Wound Infection
Surgical Site Infection
Drug: Azithromycin
Drug: Placebo

Study Type: Interventional
Study Design: Allocation: Randomized
Endpoint Classification: Efficacy Study
Intervention Model: Parallel Assignment
Masking: Double Blind (Subject, Caregiver, Investigator, Outcomes Assessor)
Primary Purpose: Prevention
Official Title: Cesarean Section Optimal Antibiotic Prophylaxis Trial

Resource links provided by NLM:

Further study details as provided by University of Alabama at Birmingham:

Primary Outcome Measures:
  • Composite of endometritis and/or wound infection and/or other post-cesarean infections (occurring within 4-6 weeks of delivery) [ Time Frame: 4-6 weeks after delivery ] [ Designated as safety issue: No ]

Secondary Outcome Measures:
  • • Individual post-cesarean infections: Endometritis, wound infection (including necrotizing fascitis), other infections including abscess, septic thrombosis, pneumonia, pyelonephritis and breast infection [ Time Frame: 4-6 weeks after delivery ] [ Designated as safety issue: No ]

Other Outcome Measures:
  • Neonatal morbidities including death, RDS, BPD, PVL, suspected or proven sepsis, NEC, IVH [ Time Frame: Up to 3 months ] [ Designated as safety issue: Yes ]
  • Pyloric stenosis [ Time Frame: up to 3 months ] [ Designated as safety issue: Yes ]
  • Post-cesarean infection by chorioamnionic colonization with ureaplasmas [ Time Frame: 4-6 weeks ] [ Designated as safety issue: No ]
    Does the impact of extended regimen vary by the presence or absence of ureaplasmas at randomization?

  • Effect modifiers [ Time Frame: 4-6 weeks ] [ Designated as safety issue: No ]
    Does the impact of extended prophylaxis vary by specific factors including obesity, wound size, duration from administration to incision

Enrollment: 2013
Study Start Date: May 2011
Study Completion Date: March 2015
Primary Completion Date: February 2015 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Placebo Comparator: Placebo
250 cc normal saline
Drug: Placebo
250 cc normal saline
Experimental: Azithromycin Drug: Azithromycin
500 mg in 250 cc normal saline 1 time dose


Ages Eligible for Study:   14 Years and older
Genders Eligible for Study:   Female
Accepts Healthy Volunteers:   No

Inclusion Criteria:


Pregnant Women aged 14 years and over at ≥ 24 weeks' viable gestation who will undergo unscheduled/non-elective cesareans with either:

  1. Labor (spontaneous or induced): active labor (ongoing contractions and at least 4cm dilated or contractions for at least 4 hours with documented cervical change of ≥1cm dilatation or ≥50% effacement), or
  2. Membrane rupture (standardized to duration of at least 4 hours prior to randomization).

Exclusion Criteria:

  • Patient unwilling or unable to provide consent
  • Multiple pregnancy
  • Known azithromycin (or other macrolide) allergy
  • Vaginal delivery
  • Elective or scheduled cesarean prior to labor or membrane rupture.
  • Azithromycin, erythromycin or other macrolide antibiotic use within 7 days of enrollment.
  • Clinical chorioamnionitis or any other active bacterial infection (e.g. pyelonephritis, pneumonia, abscess) at time of randomization.
  • Patient is unable or unlikely to follow-up after delivery (e.g. no prenatal care or a non-resident patient)
  • Fetal demise or major congenital anomaly
  • Significant liver disease defined as known cirrhosis or elevated transaminases of at least 3-fold upper limit of normal
  • Significant renal disease defined as serum creatinine known to be >2.0 mg/dl or on dialysis.
  • Active congestive heart failure (EF<45%) or pulmonary edema
  • Active diarrhea at time of delivery
  • Any patient with significant electrolyte abnormalities such as hypokalemia or hypocalcemia
  • Any patient with structural heart disease or arrhythmias, or taking any medications known to prolong the QT interval
  • Patient currently being treated with efavirenz, nelfinavir or fluconazole
  Contacts and Locations
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Please refer to this study by its identifier: NCT01235546

United States, Alabama
University of Alabama at Birmingham
Birmingham, Alabama, United States, 35233
United States, Louisiana
Ochsner Clinic Foundation
New Orleans, Louisiana, United States, 70121
United States, Mississippi
University of Mississippi Medical Center
Jackson, Mississippi, United States, 39216
United States, New York
Columbia University
New York, New York, United States, 10032
United States, North Carolina
Mission Hospital
Ashville, North Carolina, United States, 28801
University of North Carolina
Chapel Hill, North Carolina, United States, 27599-7516
United States, Texas
University of Texas Medical Branch
Galveston, Texas, United States, 77555-0587
University of Texas Health Science Center at Houston
Houston, Texas, United States, 77225
United States, Utah
University of Utah
Salt Lake City, Utah, United States, 84132
Sponsors and Collaborators
Alan Tita
University of Texas
University of North Carolina
Mission Hospital
Ochsner Health System
The University of Texas Health Science Center, Houston
Columbia University
University of Utah
University of Mississippi Medical Center
Principal Investigator: Alan TN Tita, MD, PhD University of Alabama at Birmingham
  More Information

Responsible Party: Alan Tita, Professor, University of Alabama at Birmingham Identifier: NCT01235546     History of Changes
Other Study ID Numbers: F090323006, 1R01HD064729-01A1
Study First Received: November 4, 2010
Last Updated: May 21, 2015
Health Authority: United States: Food and Drug Administration

Keywords provided by University of Alabama at Birmingham:
Cesarean section

Additional relevant MeSH terms:
Communicable Diseases
Wound Infection
Adnexal Diseases
Genital Diseases, Female
Pelvic Inflammatory Disease
Uterine Diseases
Wounds and Injuries processed this record on August 26, 2015