From the Guidelines
Cefazolin, gentamicin, and vancomycin are crucial antibiotics for treating various bacterial infections, with cefazolin typically dosed at 1-2g IV every 8 hours, gentamicin at 5-7mg/kg IV once daily, and vancomycin at 15-20mg/kg IV every 8-12 hours, all requiring careful consideration of renal function and culture-guided therapy.
Key Points
- Cefazolin is a first-generation cephalosporin effective against many gram-positive bacteria and some gram-negative organisms, commonly used for surgical prophylaxis and skin/soft tissue infections, with dose adjustments needed in renal impairment 1.
- Gentamicin is an aminoglycoside that targets gram-negative bacteria, including Pseudomonas, requiring therapeutic drug monitoring to prevent nephrotoxicity and ototoxicity, and is usually dosed at 5-7mg/kg IV once daily 1.
- Vancomycin is a glycopeptide antibiotic primarily used for serious gram-positive infections, especially methicillin-resistant Staphylococcus aureus (MRSA), typically dosed at 15-20mg/kg IV every 8-12 hours with target trough levels of 10-20 mcg/mL depending on infection type 1.
Dosage and Administration
- Cefazolin: 1-2g IV every 8 hours, with dose adjustments in renal impairment 1.
- Gentamicin: 5-7mg/kg IV once daily, with traditional dosing at 1-1.7mg/kg every 8 hours, and requiring therapeutic drug monitoring 1.
- Vancomycin: 15-20mg/kg IV every 8-12 hours, with target trough levels of 10-20 mcg/mL depending on infection type 1.
Important Considerations
- Renal function: all three antibiotics require careful consideration of the patient's renal function for appropriate dosing 1.
- Culture-guided therapy: cultures should guide therapy whenever possible to ensure targeted treatment and minimize resistance development 1.
From the FDA Drug Label
Gentamicin, an aminoglycoside, binds to the prokaryotic ribosome, inhibiting protein synthesis in susceptible bacteria. It is bactericidal in vitro against Gram-positive and Gram-negative bacteria. The FDA drug label does not answer the question about cefazolin and vancomycin, but for gentamicin:
- Mechanism of Action: Gentamicin binds to the prokaryotic ribosome, inhibiting protein synthesis in susceptible bacteria.
- Antibacterial Activity: Gentamicin has been shown to be active against most of the following bacteria, both in vitro and in clinical infections, including:
- Gram-Positive Bacteria: Staphylococcus species
- Gram-Negative Bacteria: Citrobacter species, Enterobacter species, Escherichia coli, Klebsiella species, Proteus species, Serratia species, Pseudomonas aeruginosa 2
From the Research
Overview of Antibiotics
- Cefazolin, gentamicin, and vancomycin are antibiotics used to treat various infections.
- These antibiotics have been studied in different contexts, including hemodialysis patients, open fractures, and peritoneal dialysis patients.
Cefazolin
- Cefazolin has been shown to be a safe and effective alternative to vancomycin in hemodialysis patients 3.
- It can be used in combination with gentamicin for empiric treatment of infections in hemodialysis patients 3.
- Cefazolin has also been compared to vancomycin as initial therapy for peritonitis in peritoneal dialysis patients, with no significant difference in clinical response or relapse rate 4.
Gentamicin
- Gentamicin is often used in combination with other antibiotics, such as cefazolin or vancomycin, to treat infections 3, 5, 6.
- It has been shown to be compatible with cefazolin in peritoneal dialysis solutions 6.
- Gentamicin is also being studied as part of a prophylactic treatment solution for breast implants to reduce the risk of postoperative infection 7.
Vancomycin
- Vancomycin is commonly used to treat infections in hemodialysis patients, but its use can lead to the development of resistant organisms 3.
- It has been compared to cefazolin as initial therapy for peritonitis in peritoneal dialysis patients, with no significant difference in clinical response or relapse rate 4.
- Vancomycin is also being studied as part of a prophylactic treatment solution for breast implants to reduce the risk of postoperative infection 7.
Combination Therapy
- Cefazolin plus gentamicin has been shown to be superior to vancomycin alone in treating infections in hemodialysis patients 3.
- The combination of gentamicin, vancomycin, and cefazolin is being studied as a prophylactic treatment solution for breast implants to reduce the risk of postoperative infection 7.
- Ceftriaxone plus vancomycin has been compared to cefazolin plus gentamicin as antibiotic prophylaxis for grade 3 open fractures, with no significant difference in treatment failure rates 5.