May 27, 2025

Welcome to UH EMS-I’s Pharmacy Phriday. This week, we focus on cefazolin, a medication some agencies have been administering as a pilot program. The medication should now be on all our agencies’ new drug licenses and is now available for use by all our paramedic providers.  

Cefazolin is a common antibiotic used widely in orthopedic procedural settings to prevent infections as well as in cases of known bacterial infections within the body. It is known to be a medicine that has an excellent safety profile. Its prophylactic use in the pre-hospital setting by EMS in cases of open fractures is now supported by numerous organizations, including the American College of Surgeons Committee on Trauma (ACS COT), the Orthopedic Trauma Association (OTA), the American College of Emergency Physicians (ACEP), the National Association of EMS Physicians (NAEMSP), and the National Association of Emergency Medical Technicians (NAEMT).  

Fracture-related infections are often the cause of significant orthopedic complications, such as osteomyelitis (infection of the bone) and poor healing. Early antibiotics significantly reduce the risk of fracture-related infections and improve patient outcomes. In one study, it was suggested that there was a significant increase in infectious complications when antibiotic prophylaxis was delayed longer than 66 minutes past the time of injury.1

Timely administration of antibiotics for open fractures is challenging, considering time factors from the time of injury (such as 911 access times, response times, possible prolonged extrication time, transport times, wall-time in the emergency departments, registration time, etc.). EMS can play a critical role in meeting the goal of quick use of antibiotics within that 66-minute window mentioned earlier.   

Within the UH Prehospital Care Protocol and Treatment Guidelines, the use of cefazolin is found in the “Extremity Trauma/Amputation” algorithm and is indicated in cases or suspected cases of open fractures. The signs and symptoms that might indicate such a condition include protruding bone ends and open lacerations near an injury site with the presence of crepitus or angulation or deformity. This would also apply to partial or complete amputations.  

Contraindications to the use of cefazolin within the UH protocol include a known allergy to the medication, any allergies to other cephalosporins, or allergies to penicillin. If the patient is unresponsive or the provider is unable to determine the allergy status of the patient, the medication should be withheld. Within the UH protocol, cefazolin is also not used for patients under 9 years of age or a patient weighing less than 30 kg.  

Dosing for cefazolin within the UH protocols is 2 grams IV/IO for any patient weighing more than 50 kg or 1 gram IV/IO for patients weighing 30-50 kg. Any patient weighing less than 30 kg or is less than 9 years old would require approval by medical direction.  

Before administration, cefazolin must be reconstituted and mixed as an infusion. The provider should find the cefazolin powder (provided as 1 gram per vial) and 2.5 ml sterile water for injection (SWFI) ampules in a marked bag at the bottom of the UH drug box. The provider should then draw up 2.5 ml of the sterile water into a 5 or 10cc syringe, inject the sterile water into the ampule of cefazolin and mix it by inverting the vial 10 times. 

Once mixed and inspected, the entire solution would be drawn back into the syringe (this should be about 3 ml total). To administer the medication, the solution is then added to a 100 ml bag of D5W, also found in the bottom of the drug box, mixed well, and ran as an infusion over 10 minutes (approximately 2-3 gtts/min depending upon if using a 10/gtt or 15/gtt drip set). If the required dose is 2 grams, the provider would repeat the above process but both mixtures can go into the same 100 ml D5W bag. 

While anaphylactic reactions are uncommon with cefazolin, the provider must still monitor for such side effects and treat them accordingly if they do occur.  

It is important to point out that the ABCs and standard trauma care should be completed before administering cefazolin. Do not delay necessary procedures, transport, or other trauma care to give cefazolin. Administration of the medication is often best done during the transport phase after stabilization of the patient. 

UH providers should have begun to see cefazolin added to the drug boxes after May 19, 2025. Boxes should be labeled with a sticker added to the top of the box indicating the addition of the medication. If you have any questions, please reach out to your local Medical Director or EMS Coordinator.

Until next time, stay safe!

Sincerely, 

The UH EMS-I Team 

University Hospitals 

Source:

1. Lack WD, Karunakar MA, Angerame MR, Seymour RB, Sims S, Kellam JF, Bosse MJ. Type III open tibia fractures: immediate antibiotic prophylaxis minimizes infection. J Orthop Trauma. 2015;29(1):1–6. doi:10.1097/BOT.0000000000000262