Ancef

1st Generation Cephalosporin Antibiotics

Visually inspect parenteral products for particulate matter and discoloration prior to administration whenever solution and container permit.
Reconstituted solutions may range in color from pale yellow to yellow without a change in potency.

Intermittent IV Infusion
Reconstitution/Preparation
Conventional Vials for Injection
Reconstitute vials with Sterile Water for Injection according to the manufacturer's instructions.
Shake well.
Storage: Store reconstituted solutions at room temperature or under refrigeration according to the manufacturer's instructions.
 
Bulk Vials for Injection
Reconstitute 10 g vial with 45 mL or 96 mL of diluent to yield 200 mg/mL and 100 mg/mL, respectively.
Reconstitute 20 g vial with 87 mL of diluent to yield 200 mg/mL.
Compatible IV solutions include Sterile Water for Injection, Bacteriostatic Water for Injection, or 0.9% Sodium Chloride Injection.
Further dilution is required; pharmacy bulk vials are not intended for administration via direct IV injection.
Storage: Use bulk vials within 4 hours of initial entry.
 
ADD-Vantage vials
Reconstituted in 50 or 100 mL flexible containers with 0.9% Sodium Chloride Injection or 5% Dextrose Injection. ADD-Vantage vials are not to be used for direct IV injection or IM injection.
Storage: The reconstituted solution is stable for 24 hours at room temperature.
 
Frozen Pre-mixed Bags
Thaw frozen container at room temperature (20 to 25 degrees C or 68 to 77 degrees F) or under refrigeration (2 to 8 degrees C or 36 to 46 degrees F).
Do not force thaw by immersion in water baths or by microwave irradiation.
Storage: The thawed solution remains stable for 30 days under refrigeration (5 degrees C or 41 degrees F) or 48 hours at room temperature (25 degrees C or 77 degrees F). Do not refreeze.
 
DUPLEX Drug Delivery System
Use only if container and seals are intact. To inspect the drug powder for foreign matter or discoloration, peel the foil strip from the drug chamber.
Protect from light after removal of foil strip.
Allow refrigerated product to reach room temperature before patient use.
Unfold the container and point the set port downward. Starting at the hanger tab end, fold the container just below the diluent meniscus trapping all air above the fold.
To activate, squeeze the folded diluent chamber until the seal between the diluent and powder opens, releasing diluent into the drug powder chamber.
Agitate the liquid-powder mixture until the drug powder completely dissolves.
Do not use plastic containers in series connections as this may result in air embolism due to residual air being drawn from the primary container before administration of the fluid from the secondary container is complete.
Do not introduce additives into the container.
Storage: If the foil strip is removed, refold container and latch the side tab until ready to activate and use within 7 days. After reconstitution (activation), use within 24 hours if stored at room temperature or within 7 days if stored under refrigeration.
 
Dilution
ADD-Vantage vials: After reconstitution, no further dilution is required.
Conventional/Bulk vials:
Adults: Further dilute the reconstituted solution in 50 to 100 mL of a compatible IV solution according to the manufacturer's instructions.
Pediatrics: Further dilute the reconstituted solution in compatible IV solution according to the manufacturer's instructions to a concentration of 10 to 40 mg/mL.
Storage: Store diluted solutions at room temperature or under refrigeration according to the manufacturer's instructions.
 
Intermittent IV Infusion Administration
Infuse IV over approximately 15 to 30 minutes.
 
Intermittent IV Push
Reconstitution
Reconstitute the 500 mg and 1 g vials with 2 mL and 2.5 mL of Sterile Water for Injection to yield concentrations of 225 mg/mL and 330 mg/mL, respectively.
Storage: Reconstituted solutions are stable for 24 hours at room temperature or for 10 days if stored under refrigeration (5 degrees C or 41 degrees F).
 
Dilution
Further dilute the reconstituted solution with 5 to 10 mL of Sterile Water for Injection.
A maximum concentration of 100 mg/mL is recommended for pediatric patients.
Storage: Diluted solutions are stable for 24 hours at room temperature or for 10 days if stored under refrigeration (5 degrees C or 41 degrees F).
 
Intermittent IV Push Administration
Administer slow IV push over at least 3 to 5 minutes.
Doses have been administered over 2 to 5 minutes in adult studies.

Reconstitution
Reconstitute the 500 mg and 1 g vials with 2 mL and 2.5 mL of Sterile Water for Injection to yield concentrations of 225 mg/mL and 330 mg/mL, respectively.
Storage: Reconstituted solution is stable for 24 hours at room temperature or 10 days refrigerated.[51610]
 
Intramuscular Injection
Inject deeply into a large muscle mass (e.g., anterolateral thigh or deltoid [children and adolescents only]).[51610]

interstitial nephritis / Delayed / Incidence not known
azotemia / Delayed / Incidence not known
renal failure (unspecified) / Delayed / Incidence not known
anaphylactoid reactions / Rapid / Incidence not known
Stevens-Johnson syndrome / Delayed / Incidence not known
serum sickness / Delayed / Incidence not known
erythema multiforme / Delayed / Incidence not known
toxic epidermal necrolysis / Delayed / Incidence not known
acute generalized exanthematous pustulosis (AGEP) / Delayed / Incidence not known
aplastic anemia / Delayed / Incidence not known
hemolytic anemia / Delayed / Incidence not known
pancytopenia / Delayed / Incidence not known
seizures / Delayed / Incidence not known
C. difficile-associated diarrhea / Delayed / Incidence not known

oral ulceration / Delayed / Incidence not known
leukopenia / Delayed / Incidence not known
neutropenia / Delayed / Incidence not known
thrombocytopenia / Delayed / Incidence not known
eosinophilia / Delayed / Incidence not known
thrombocytosis / Delayed / Incidence not known
hypoprothrombinemia / Delayed / Incidence not known
bleeding / Early / Incidence not known
phlebitis / Rapid / Incidence not known
confusion / Early / Incidence not known
hypotension / Rapid / Incidence not known
elevated hepatic enzymes / Delayed / Incidence not known
hepatitis / Delayed / Incidence not known
cholestasis / Delayed / Incidence not known
candidiasis / Delayed / Incidence not known
pseudomembranous colitis / Delayed / Incidence not known
superinfection / Delayed / Incidence not known
vaginitis / Delayed / Incidence not known

nausea / Early / 14.8-14.8
injection site reaction / Rapid / 6.6-6.6
headache / Early / 4.9-4.9
pruritus / Rapid / Incidence not known
urticaria / Rapid / Incidence not known
rash / Early / Incidence not known
fever / Early / Incidence not known
anorexia / Delayed / Incidence not known
diarrhea / Early / Incidence not known
vomiting / Early / Incidence not known
flatulence / Early / Incidence not known
pyrosis (heartburn) / Early / Incidence not known
dizziness / Early / Incidence not known
drowsiness / Early / Incidence not known
weakness / Early / Incidence not known
pruritus ani / Early / Incidence not known

Ancef, Kefzol

Rx

Parenteral first-generation cephalosporin
Used for respiratory tract, urinary tract, skin and skin structure, biliary tract, bone and joint, and genital infections as well as sepsis, endocarditis, and perioperative prophylaxis
Greater activity against gram-positive bacteria than most other cephalosporins, but limited activity against gram-negative bacteria

250 to 500 mg IV or IM every 8 hours.

25 to 50 mg/kg/day (Max: 1.5 g/day) IV or IM divided every 6 to 8 hours.

50 mg/kg/dose IV or IM every 8 hours.

50 mg/kg/dose IV or IM every 12 hours.

25 mg/kg/dose IV or IM every 8 hours.

25 mg/kg/dose IV or IM every 12 hours.

500 mg to 1 g IV or IM every 6 to 8 hours.

25 to 100 mg/kg/day (Max: 4 g/day) IV or IM divided every 6 to 8 hours.

50 mg/kg/dose IV or IM every 8 hours.

50 mg/kg/dose IV or IM every 12 hours.

25 mg/kg/dose IV or IM every 8 hours.

25 mg/kg/dose IV or IM every 12 hours.

1 g IV or IM every 12 hours.

25 to 50 mg/kg/day (Max: 2 g/day) IV or IM divided every 6 to 8 hours.

500 mg to 1 g IV or IM every 6 to 8 hours.

25 to 100 mg/kg/day (Max: 4 g/day) IV or IM divided every 6 to 8 hours.

25 to 100 mg/kg/day (Max: 4 g/day) IV or IM divided every 6 to 8 hours. Infants younger than 2 to 3 months are at risk for systemic infection and rapid change in their clinical condition. Treat UTIs as presumed pyelonephritis in these patients.

50 mg/kg/dose IV or IM every 8 hours. Neonates are at risk for systemic infection and rapid change in their clinical condition. Treat UTIs as presumed pyelonephritis in these patients.

50 mg/kg/dose IV or IM every 12 hours. Neonates are at risk for systemic infection and rapid change in their clinical condition. Treat UTIs as presumed pyelonephritis in these patients.

25 mg/kg/dose IV or IM every 8 hours. Neonates are at risk for systemic infection and rapid change in their clinical condition. Treat UTIs as presumed pyelonephritis in these patients.

25 mg/kg/dose IV or IM every 12 hours. Neonates are at risk for systemic infection and rapid change in their clinical condition. Treat UTIs as presumed pyelonephritis in these patients.

Not recommended by guidelines. The FDA-approved dosage is 1 to 1.5 g IV or IM every 6 hours for group A beta-hemolytic streptococci. In rare instances, doses up to 12 g/day IV or IM have been used.

100 mg/kg/day (Max: 12 g/day) IV or IM divided every 8 hours for 4 weeks as an alternative.

50 mg/kg/dose IV or IM every 8 hours for 4 weeks as an alternative.

50 mg/kg/dose IV or IM every 12 hours for 4 weeks as an alternative.

25 mg/kg/dose IV or IM every 8 hours for 4 weeks as an alternative.

25 mg/kg/dose IV or IM every 12 hours for 4 weeks as an alternative.

2 g IV every 8 hours for 4 weeks.

2 g IV every 8 hours for 6 weeks.

2 g IV every 8 hours for 6 weeks as an alternative. The FDA-approved dosage is 1 to 1.5 g IV or IM every 6 hours. In rare instances, doses up to 12 g/day IV or IM have been used.

100 mg/kg/day (Max: 12 g/day) IV or IM divided every 8 hours for 4 to 6 weeks as an alternative; consider the addition of gentamicin for 3 to 5 days.

50 mg/kg/dose IV or IM every 8 hours for 4 to 6 weeks as an alternative; consider the addition of gentamicin for 3 to 5 days.

50 mg/kg/dose IV or IM every 12 hours for 4 to 6 weeks as an alternative; consider the addition of gentamicin for 3 to 5 days.

25 mg/kg/dose IV or IM every 8 hours for 4 to 6 weeks as an alternative; consider the addition of gentamicin for 3 to 5 days.

25 mg/kg/dose IV or IM every 12 hours for 4 to 6 weeks as an alternative; consider the addition of gentamicin for 3 to 5 days.

2 g IV every 8 hours plus rifampin for at least 6 weeks and gentamicin for 2 weeks as an alternative. The FDA-approved dosage is 1 to 1.5 g IV or IM every 6 hours. In rare instances, doses up to 12 g/day IV or IM have been used.

100 mg/kg/day (Max: 12 g/day) IV or IM divided every 8 hours plus rifampin for at least 6 weeks and gentamicin for 2 weeks as an alternative.

50 mg/kg/dose IV or IM every 8 hours plus rifampin for at least 6 weeks and gentamicin for 2 weeks as an alternative.

50 mg/kg/dose IV or IM every 12 hours plus rifampin for at least 6 weeks and gentamicin for 2 weeks as an alternative.

25 mg/kg/dose IV or IM every 8 hours plus rifampin for at least 6 weeks and gentamicin for 2 weeks as an alternative.

25 mg/kg/dose IV or IM every 12 hours plus rifampin for at least 6 weeks and gentamicin for 2 weeks as an alternative.

100 mg by subconjunctival injection or 1 to 2.5 mg by intracameral injection is optional at the end of the procedure. Perioperative antisepsis with povidone-iodine is recommended. The necessity of continuing topical antimicrobials postoperatively has not been established.

3 g IV as a single dose within 30 to 60 minutes prior to the surgical incision; consider intraoperative redosing 4 hours from the first preoperative dose. May continue 3 g IV every 6 to 8 hours for no more than 24 hours post-operatively if necessary.   Cefazolin is FDA-approved for contaminated or potentially contaminated procedures, including vaginal hysterectomy and cholecystectomy in high-risk patients, as well as in surgical patients in whom infection at the operative site would present a serious risk (e.g., prosthetic arthroplasty).  Guidelines recommend cefazolin monotherapy for gastrointestinal, biliary tract, hernia repair, clean head and neck with prosthesis, neurosurgical, urogynecology, orthopedic, vascular, certain transplantation, and plastic surgery procedures. Cefazolin is recommended as part of combination therapy for appendectomy, obstructed gastrointestinal, colorectal, clean-contaminated head and neck, and urologic with prosthesis or clean-contaminated procedures.

1 g IV or IM or 2 g IV as a single dose within 30 to 60 minutes prior to the surgical incision; consider intraoperative redosing 4 hours from the first preoperative dose. May continue 500 mg to 1 g IV or IM or 2 g IV every 6 to 8 hours for no more than 24 hours post-operatively if necessary.   Cefazolin is FDA-approved for contaminated or potentially contaminated procedures, including vaginal hysterectomy and cholecystectomy in high-risk patients, as well as in surgical patients in whom infection at the operative site would present a serious risk (e.g., prosthetic arthroplasty).  Guidelines recommend cefazolin monotherapy for gastrointestinal, biliary tract, hernia repair, clean head and neck with prosthesis, neurosurgical, urogynecology, orthopedic, vascular, certain transplantation, and plastic surgery procedures. Cefazolin is recommended as part of combination therapy for appendectomy, obstructed gastrointestinal, colorectal, clean-contaminated head and neck, and urologic with prosthesis or clean-contaminated procedures.

2 g IV as a single dose within 30 to 60 minutes prior to the surgical incision; consider intraoperative redosing 4 hours from the first preoperative dose. May continue 500 mg to 1 g IV or IM every 6 to 8 hours for no more than 24 hours post-operatively if necessary.   Cefazolin is FDA-approved for contaminated or potentially contaminated procedures, including cholecystectomy in high-risk patients, as well as in surgical patients in whom infection at the operative site would present a serious risk (e.g., prosthetic arthroplasty). Guidelines recommend cefazolin monotherapy for gastrointestinal, biliary tract, hernia repair, clean head and neck with prosthesis, neurosurgical, urogynecology, orthopedic, vascular, certain transplantation, and plastic surgery procedures. Cefazolin is recommended as part of combination therapy for appendectomy, obstructed gastrointestinal, colorectal, clean-contaminated head and neck, and urologic with prosthesis or clean-contaminated procedures.

1 g IV or IM as a single dose within 30 to 60 minutes prior to the surgical incision; consider intraoperative redosing 4 hours from the first preoperative dose. May continue 500 mg to 1 g IV or IM every 6 to 8 hours for no more than 24 hours post-operatively if necessary.   Cefazolin is FDA-approved for contaminated or potentially contaminated procedures, including cholecystectomy in high-risk patients, as well as in surgical patients in whom infection at the operative site would present a serious risk (e.g., prosthetic arthroplasty). Guidelines recommend cefazolin monotherapy for gastrointestinal, biliary tract, hernia repair, clean head and neck with prosthesis, neurosurgical, urogynecology, orthopedic, vascular, certain transplantation, and plastic surgery procedures. Cefazolin is recommended as part of combination therapy for appendectomy, obstructed gastrointestinal, colorectal, clean-contaminated head and neck, and urologic with prosthesis or clean-contaminated procedures.

30 mg/kg (Max: 2 g/dose) IV or IM as a single dose within 60 minutes prior to the surgical incision; consider intraoperative redosing 4 hours from the first preoperative dose. May continue 30 mg/kg (Max: 2 g/dose) IV or IM every 6 to 8 hours for no more than 24 hours post-operatively if necessary. Guidelines recommend cefazolin monotherapy for gastrointestinal, biliary tract, hernia repair, clean head and neck with prosthesis, neurosurgical, urogynecology, orthopedic, vascular, certain transplantation, and plastic surgery procedures. Cefazolin is recommended as part of combination therapy for appendectomy, obstructed gastrointestinal, colorectal, clean-contaminated head and neck, and urologic with prosthesis or clean-contaminated procedures.

3 g IV as a single dose within 30 to 60 minutes prior to the surgical incision; consider intraoperative redosing 4 hours from the first preoperative dose. May continue 3 g IV every 6 to 8 hours for no more than 24 hours post-operatively if necessary.  Cefazolin is FDA-approved in surgical patients in whom infection at the operative site would present a serious risk (e.g., open-heart surgery). Where the occurrence of infection may be particularly devastating, prophylaxis may be continued for up to 3 to 5 days. However, a longer prophylaxis duration of 48 hours (or more) for certain cardiothoracic procedures is controversial. Guidelines recommend cefazolin monotherapy for cardiothoracic surgery procedures.

1 g IV or IM or 2 g IV as a single dose within 30 to 60 minutes prior to the surgical incision; consider intraoperative redosing 4 hours from the first preoperative dose. May continue 500 mg to 1 g IV or IM or 2 g IV every 6 to 8 hours for no more than 24 hours post-operatively if necessary.  Cefazolin is FDA-approved in surgical patients in whom infection at the operative site would present a serious risk (e.g., open-heart surgery). Where the occurrence of infection may be particularly devastating, prophylaxis may be continued for up to 3 to 5 days. However, a longer prophylaxis duration of 48 hours (or more) for certain cardiothoracic procedures is controversial. Guidelines recommend cefazolin monotherapy for cardiothoracic surgery procedures.

2 g IV as a single dose within 30 to 60 minutes prior to the surgical incision; consider intraoperative redosing 4 hours from the first preoperative dose. May continue 500 mg to 1 g IV or IM every 6 to 8 hours for no more than 24 hours post-operatively if necessary.   Cefazolin is FDA-approved in surgical patients in whom infection at the operative site would present a serious risk (e.g., open-heart surgery). Where the occurrence of infection may be particularly devastating, prophylaxis may be continued for up to 3 to 5 days. However, a longer prophylaxis duration of 48 hours (or more) for certain cardiothoracic procedures is controversial. Guidelines recommend cefazolin monotherapy for cardiothoracic surgery procedures.

1 g IV or IM as a single dose within 30 to 60 minutes prior to the surgical incision; consider intraoperative redosing 4 hours from the first preoperative dose. May continue 500 mg to 1 g IV or IM every 6 to 8 hours for no more than 24 hours post-operatively if necessary.   Cefazolin is FDA-approved in surgical patients in whom infection at the operative site would present a serious risk (e.g., open-heart surgery). Where the occurrence of infection may be particularly devastating, prophylaxis may be continued for up to 3 to 5 days. However, a longer prophylaxis duration of 48 hours (or more) for certain cardiothoracic procedures is controversial. Guidelines recommend cefazolin monotherapy for cardiothoracic surgery procedures.

30 mg/kg (Max: 2 g/dose) IV or IM as a single dose within 30 to 60 minutes prior to the surgical incision; consider intraoperative redosing 4 hours from the first preoperative dose. May continue 30 mg/kg (Max: 2 g/dose) IV or IM every 6 to 8 hours for no more than 24 hours post-operatively if necessary. A longer prophylaxis duration of 48 hours for certain cardiothoracic procedures is controversial. Guidelines recommend cefazolin monotherapy for cardiothoracic surgery procedures.

500 mg to 1 g IV or IM every 6 to 8 hours. The usual maximum dose is 6 g/day. Not recommended for the treatment of sexually transmitted epididymitis.

25 to 100 mg/kg/day (Max: 6 g/day) IV or IM divided every 8 hours.

50 mg/kg/dose IV or IM every 8 hours.

50 mg/kg/dose IV or IM every 12 hours.

25 mg/kg/dose IV or IM every 8 hours.

25 mg/kg/dose IV or IM every 12 hours.

250 to 500 mg IV or IM every 8 hours.

25 to 50 mg/kg/day (Max: 1.5 g/day) IV or IM divided every 6 to 8 hours.

50 mg/kg/dose IV or IM every 8 hours.

50 mg/kg/dose IV or IM every 12 hours.

25 mg/kg/dose IV or IM every 8 hours.

25 mg/kg/dose IV or IM every 12 hours.

150 mg/kg/day (Max: 6 g/day) IV divided every 8 hours for 10 days.[46963]

500 mg to 1 g IV or IM every 6 to 8 hours.

25 to 100 mg/kg/day (Max: 4 g/day) IV or IM divided every 6 to 8 hours.

50 mg/kg/dose IV or IM every 8 hours.

50 mg/kg/dose IV or IM every 12 hours.

25 mg/kg/dose IV or IM every 8 hours.

25 mg/kg/dose IV or IM every 12 hours.

1 to 1.5 g IV or IM every 6 hours. In rare instances, doses up to 12 g/day IV or IM have been used.

100 mg/kg/day (Max: 6 g/day) IV or IM divided every 6 to 8 hours. In rare instances, doses up to 12 g/day IV or IM have been used.

500 mg IV or IM every 12 hours.

2 g IV every 8 hours for S. aureus infections. The FDA-labeled dosage is 1 to 1.5 g IV or IM every 6 hours. In rare instances, doses up to 12 g/day IV or IM have been used.

100 mg/kg/day (Max: 6 g/day) IV or IM divided every 8 hours.  Guidelines recommend cefazolin for 7 to 14 days as a first-line treatment option for S. aureus bacteremia.

50 mg/kg/dose IV or IM every 8 hours. Guidelines recommend cefazolin for at least 14 days as a first-line treatment option for S. aureus bacteremia.

50 mg/kg/dose IV or IM every 12 hours. Guidelines recommend cefazolin for at least 14 days as a first-line treatment option for S. aureus bacteremia.

25 mg/kg/dose IV or IM every 8 hours. Guidelines recommend cefazolin for at least 14 days as a first-line treatment option for S. aureus bacteremia.

25 mg/kg/dose IV or IM every 12 hours. Guidelines recommend cefazolin for at least 14 days as a first-line treatment option for S. aureus bacteremia.

1 g IV every 8 hours for 10 to 14 days.

25 to 75 mg/kg/day IV divided every 8 hours.[31700] [57437] [64275] Up to 100 mg/kg/day IV divided every 8 hours for severe infections.[31700]

50 mg/kg/dose IV every 8 hours.

50 mg/kg/dose IV every 12 hours.

25 mg/kg/dose IV every 8 hours.

25 mg/kg/dose IV every 12 hours.

1 g IV or IM every 8 hours for 5 to 14 days.

50 mg/kg/day (Max: 3 g/day) IV or IM divided every 8 hours for 5 to 14 days.

50 mg/kg/dose IV or IM every 8 hours for 5 to 14 days.

50 mg/kg/dose IV or IM every 12 hours for 5 to 14 days.

25 mg/kg/dose IV or IM every 8 hours for 5 to 14 days.

25 mg/kg/dose IV or IM every 12 hours for 5 to 14 days.

1 g IV every 8 hours for 5 to 10 days plus incision and drainage. 

50 mg/kg/day (Max: 3 g/day) IV divided every 8 hours for 5 to 10 days plus incision and drainage.

50 mg/kg/dose IV every 8 hours for 5 to 10 days plus incision and drainage.

50 mg/kg/dose IV every 12 hours for 5 to 10 days plus incision and drainage.

25 mg/kg/dose IV every 8 hours for 5 to 10 days plus incision and drainage.

25 mg/kg/dose IV every 12 hours for 5 to 10 days plus incision and drainage.

1 g IV every 8 hours for incisional surgical site infections of the trunk or extremity away from the axilla or perineum.

1 g IV every 8 hours for 14 to 21 days.

50 mg/kg/day (Max: 3 g/day) IV divided every 8 hours for 14 to 21 days.

50 mg/kg/dose IV every 8 hours for 14 to 21 days.

50 mg/kg/dose IV every 12 hours for 14 to 21 days.

25 mg/kg/dose IV every 8 hours for 14 to 21 days.

25 mg/kg/dose IV every 12 hours for 14 to 21 days.

1 g IV or IM every 8 hours for 5 to 14 days.

100 mg/kg/day (Max: 3 g/day) IV or IM divided every 8 hours for 5 to 14 days.

50 mg/kg/dose IV or IM every 8 hours for 5 to 14 days.

50 mg/kg/dose IV or IM every 12 hours for 5 to 14 days.

25 mg/kg/dose IV or IM every 8 hours for 5 to 14 days.

25 mg/kg/dose IV or IM every 12 hours for 5 to 14 days.

1 g IV every 8 hours until further debridement is not necessary, the patient has improved clinically, and fever has been absent for 48 to 72 hours for MSSA infections.

100 mg/kg/day (Max: 3 g/day) IV divided every 8 hours until further debridement is not necessary, the patient has improved clinically, and fever has been absent for 48 to 72 hours for MSSA infections.

50 mg/kg/dose IV every 8 hours until further debridement is not necessary, the patient has improved clinically, and fever has been absent for 48 to 72 hours for MSSA infections.

50 mg/kg/dose IV every 12 hours until further debridement is not necessary, the patient has improved clinically, and fever has been absent for 48 to 72 hours for MSSA infections.

25 mg/kg/dose IV every 8 hours until further debridement is not necessary, the patient has improved clinically, and fever has been absent for 48 to 72 hours for MSSA infections.

25 mg/kg/dose IV every 12 hours until further debridement is not necessary, the patient has improved clinically, and fever has been absent for 48 to 72 hours for MSSA infections.

250 to 500 mg IV or IM every 8 hours.

25 to 50 mg/kg/day (Max: 1.5 g/day) IV or IM divided every 6 to 8 hours.

1 g IV or IM as a single dose given 30 to 60 minutes before procedure as an alternative for patients allergic to penicillin and/or unable to take oral medications. Prophylaxis is recommended for at-risk cardiac patients who are undergoing dental procedures that involve manipulation of gingival tissue, manipulation of the periapical region of teeth, or perforation of the oral mucosa.

50 mg/kg/dose (Max: 1 g/dose) IV or IM as a single dose given 30 to 60 minutes before procedure as an alternative for patients allergic to penicillin and/or unable to take oral medications. Prophylaxis is recommended for at-risk cardiac patients who are undergoing dental procedures that involve manipulation of gingival tissue, manipulation of the periapical region of teeth, or perforation of the oral mucosa.

2 g IV loading dose at the time of labor or rupture of membranes, followed by 1 g IV every 8 hours until delivery. Cefazolin is recommended as an alternative for persons with a low-risk penicillin allergy. Antibiotics administered for at least 4 hours before delivery have been found to be highly effective at preventing the transmission of Group B Streptococcus.

2 g IV loading dose at the time of labor or rupture of membranes, followed by 1 g IV every 8 hours until delivery. Cefazolin is recommended as an alternative for persons with a low-risk penicillin allergy. Antibiotics administered for at least 4 hours before delivery have been found to be highly effective at preventing the transmission of Group B Streptococcus.

1 to 2 g IV every 8 hours for 4 to 6 weeks.

100 to 150 mg/kg/day (Max: 12 g/day) IV divided every 6 to 8 hours. Treat for 2 to 4 days or until clinically improved, followed by oral step-down therapy for a total duration of 3 to 4 weeks for uncomplicated cases. A longer course (i.e., 4 to 6 weeks or longer) may be needed for severe or complicated infections.

100 to 150 mg/kg/day IV divided every 6 to 8 hours. Treat for 14 to 21 days or until clinically improved, followed by oral step-down therapy for a total duration of 4 to 6 weeks. A longer course (several months) may be needed for severe or complicated infections.

50 mg/kg/dose IV every 8 hours. Treat for 14 to 21 days or until clinically improved, followed by oral step-down therapy for a total duration of 4 to 6 weeks. A longer course (several months) may be needed for severe or complicated infections.

50 mg/kg/dose IV every 12 hours. Treat for 14 to 21 days or until clinically improved, followed by oral step-down therapy for a total duration of 4 to 6 weeks. A longer course (several months) may be needed for severe or complicated infections.

25 mg/kg/dose IV every 8 hours. Treat for 14 to 21 days or until clinically improved, followed by oral step-down therapy for a total duration of 4 to 6 weeks. A longer course (several months) may be needed for severe or complicated infections.

25 mg/kg/dose IV every 12 hours. Treat for 14 to 21 days or until clinically improved, followed by oral step-down therapy for a total duration of 4 to 6 weeks. A longer course (several months) may be needed for severe or complicated infections.

1 to 2 g IV every 8 hours. Treat for 1 to 2 weeks or until clinically improved, followed by oral step-down therapy for 2 to 4 weeks.

100 to 150 mg/kg/day (Max: 12 g/day) IV divided every 6 to 8 hours. Treat for 2 to 4 days or until clinically improved, followed by oral step-down therapy for a total duration of 2 to 3 weeks for uncomplicated cases. A longer course (i.e., 4 to 6 weeks or longer) may be needed for septic hip arthritis or severe or complicated infections.

100 to 150 mg/kg/day IV divided every 6 to 8 hours. Treat for 14 to 21 days or until clinically improved, followed by oral step-down therapy for a total duration of 4 to 6 weeks. A longer course (several months) may be needed for severe or complicated infections.

50 mg/kg/dose IV every 8 hours. Treat for 14 to 21 days or until clinically improved, followed by oral step-down therapy for a total duration of 4 to 6 weeks. A longer course (several months) may be needed for severe or complicated infections.

50 mg/kg/dose IV every 12 hours. Treat for 14 to 21 days or until clinically improved, followed by oral step-down therapy for a total duration of 4 to 6 weeks. A longer course (several months) may be needed for severe or complicated infections.

25 mg/kg/dose IV every 8 hours. Treat for 14 to 21 days or until clinically improved, followed by oral step-down therapy for a total duration of 4 to 6 weeks. A longer course (several months) may be needed for severe or complicated infections.

25 mg/kg/dose IV every 12 hours. Treat for 14 to 21 days or until clinically improved, followed by oral step-down therapy for a total duration of 4 to 6 weeks. A longer course (several months) may be needed for severe or complicated infections.

1 to 2 g IV every 8 hours in combination with rifampin for 2 to 6 weeks, followed by oral step-down therapy, which may be followed by long-term suppressive therapy.

1 to 2 g IV every 8 hours for 2 to 3 weeks. Generally, 2 weeks is appropriate for most patients; immunocompromised patients may require a longer duration.

100 to 150 mg/kg/day (Max: 12 g/day) IV divided every 6 to 8 hours for 2 to 3 weeks. Generally, 2 weeks is appropriate for most patients; immunocompromised patients may require a longer duration.

1 to 2 g IV every 8 hours for 6 weeks.

1 g IV or IM every 6 to 8 hours or 2 g IV every 8 hours as part of combination therapy for 3 to 7 days. Complicated infections include peritonitis and appendicitis complicated by rupture, and intraabdominal abscess.

25 to 100 mg/kg/day (Max: 6 g/day) IV or IM divided every 8 hours as part of combination therapy for 3 to 7 days. Complicated infections include peritonitis and appendicitis complicated by rupture, and intraabdominal abscess.

50 mg/kg/dose IV or IM every 8 hours as part of combination therapy for 7 to 10 days.

50 mg/kg/dose IV or IM every 12 hours as part of combination therapy for 7 to 10 days.

25 mg/kg/dose IV or IM every 8 hours as part of combination therapy for 7 to 10 days.

25 mg/kg/dose IV or IM every 12 hours as part of combination therapy for 7 to 10 days.

15 to 20 mg/kg/dose intraperitoneally every 24 hours for 14 to 21 days.

20 mg/kg/dose intraperitoneally every 24 hours for 14 to 21 days.

500 mg/L intraperitoneal loading dose, followed by 125 mg/L in each dialysate exchange. Treat for 14 to 21 days.

500 mg/L intraperitoneal loading dose, followed by 125 mg/L in each dialysate exchange. Treat for 14 to 21 days.

3 g IV every 6 to 8 hours for 1 to 3 days.

2 g IV every 6 to 8 hours for 1 to 3 days.

1 g IV every 6 to 8 hours for 1 to 3 days.

25 to 75 mg/kg/day (Max: 6 g/day) IV divided every 8 hours for 1 to 3 days.

3 g IV every 6 to 8 hours plus metronidazole for 1 day after definitive washout.

2 g IV every 6 to 8 hours plus metronidazole for 1 day after definitive washout.

1 g IV every 6 to 8 hours plus metronidazole for 1 day after definitive washout.

25 to 75 mg/kg/day (Max: 6 g/day) IV divided every 8 hours plus metronidazole for 1 day after definitive washout.

3 g IV every 6 to 8 hours for 1 day. Add metronidazole for penetrating chest trauma with esophageal disruption and continue for 1 day after definitive washout.

2 g IV every 6 to 8 hours for 1 day. Add metronidazole for penetrating chest trauma with esophageal disruption and continue for 1 day after definitive washout.

1 g IV every 6 to 8 hours for 1 day. Add metronidazole for penetrating chest trauma with esophageal disruption and continue for 1 day after definitive washout.

25 to 75 mg/kg/day (Max: 6 g/day) IV divided every 8 hours. Add metronidazole for penetrating chest trauma with esophageal disruption and continue for 1 day after definitive washout.

3 g IV every 6 to 8 hours for 5 days or until CSF leak is closed, whichever is longer. Add metronidazole for penetrating spinal cord injury if abdominal cavity is involved and consider adding metronidazole for penetrating brain injury if gross contamination with organic debris.

2 g IV every 6 to 8 hours for 5 days or until CSF leak is closed, whichever is longer. Add metronidazole for penetrating spinal cord injury if abdominal cavity is involved and consider adding metronidazole for penetrating brain injury if gross contamination with organic debris.

1 g IV every 6 to 8 hours for 5 days or until CSF leak is closed, whichever is longer. Add metronidazole for penetrating spinal cord injury if abdominal cavity is involved and consider adding metronidazole for penetrating brain injury if gross contamination with organic debris.

25 to 75 mg/kg/day (Max: 6 g/day) IV divided every 8 hours for 5 days or until CSF leak is closed, whichever is longer. Add metronidazole for penetrating spinal cord injury if abdominal cavity is involved and consider adding metronidazole for penetrating brain injury if gross contamination with organic debris.

2 g IV every 8 hours during the intrapartum period as part of alternative combination therapy. Give 1 additional dose after cesarean delivery; an additional dose is generally not needed after vaginal delivery. Other risk factors such as bacteremia or persistent postpartum fever may require additional therapy.

2 g IV every 8 hours during the intrapartum period as part of alternative combination therapy. Give 1 additional dose after cesarean delivery; an additional dose is generally not needed after vaginal delivery. Other risk factors such as bacteremia or persistent postpartum fever may require additional therapy.

†Indicates off-label use

Specific guidelines for dosage adjustment in hepatic impairment are not available; it appears that no dosage adjustments are needed.

Adult patients (FDA-approved labeling) [31700]
CrCl more than 54 mL/minute: No dosage adjustment needed.
CrCl 35 to 54 mL/minute: Administer every 8 hours or longer.
CrCl 11 to 34 mL/minute: After a normal loading dose, reduce maintenance dose by 50% and administer every 12 hours.
CrCl 10 mL/minute or less: After a normal loading dose, reduce the recommended dose by 50% and administer every 18 to 24 hours.
 
Adult patients (alternative)† [32569]
CrCl more than 50 mL/minute: No dosage adjustment needed.
CrCl 10 to 50 mL/minute: Administer the usual dose every 12 hours.
CrCl less than 10 mL/minute: Reduce the recommended dose by 50% and administer every 24 to 48 hours.
 
Pediatric patients (FDA-approved labeling) [31700]
CrCl more than 70 mL/minute: No dosage adjustment needed.
CrCl 40 to 70 mL/minute: After a normal loading dose, administer 60% of the normal daily dose divided every 12 hours.
CrCl 20 to 39 mL/minute: After a normal loading dose, administer 25% of the normal daily dose divided every 12 hours.
CrCl 5 to 19 mL/minute: After a normal loading dose, administer 10% of the normal daily dose divided every 24 hours.
 
Pediatric patients (alternative)† [32569]
The following dose adjustments are based on a usual pediatric dose of 50 to 100 mg/kg/day IV divided every 8 hours:
GFR 30 mL/minute/1.73m2 or more: No dosage adjustment needed.
GFR 10 to 29 mL/minute/1.73m2: 25 mg/kg/dose (Max: 2 g/dose) IV every 12 hours.
GFR less than 10 mL/minute/1.73m2: 25 mg/kg/dose (Max: 2 g/dose) IV every 24 hours.
 
Intermittent hemodialysis†
Adult patients
500 mg to 1 g IV every 24 hours; administer after hemodialysis on dialysis days. Alternatively, administer 1 to 2 IV every 48 to 72 hours after hemodialysis.[42303] Other recommendations suggest 15 to 20 mg/kg IV after hemodialysis.[32569]
 
Pediatric patients
25 mg/kg/dose (Max: 2 g/dose) IV every 24 hours.[32569]
 
Peritoneal dialysis†
Adult patients
500 mg IV every 12 hours.[32569]
 
Pediatric patients
25 mg/kg/dose (Max: 2 g/dose) IV every 24 hours.[32569]
 
Continuous renal replacement therapy (CRRT)†
NOTE: Various CRRT modalities include continuous venovenous hemofiltration (CVVH), continuous venovenous hemodialysis (CVVHD), continuous venovenous hemodiafiltration (CVVHDF), continuous venovenous high-flux hemodialysis (CVVHFD), continuous arteriovenous hemofiltration (CAVH), continuous arteriovenous hemodialysis (CAVHD), and continuous arteriovenous hemodiafiltration (CAVHDF). Dosing should take into consideration patient-specific factors (e.g., intrinsic renal function), type of infection, the duration of renal replacement therapy, the effluent flow rate, and the replacement solution administered.[42303]
 
Adult patients
Administering the usual dose every 12 hours has generally been suggested for CRRT.[32569] More specifically, consider a 2 g IV loading dose, then 1 to 2 g IV every 12 hours for CVVH and a 2 g IV loading dose, then 1 g IV every 8 hours or 2 g IV every 12 hours for CVVHD or CVVHDF.[34038] [42303]
 
Pediatric patients
25 mg/kg/dose (Max: 2 g/dose) IV every 8 hours.[32569]

Clofarabine: (Moderate) Concomitant use of clofarabine, a substrate of OAT1 and OAT3, and cefazolin, an inhibitor of OAT1 and OAT3, may result in increased clofarabine levels. Therefore, monitor for signs of clofarabine toxicity such as gastrointestinal toxicity (e.g., nausea, vomiting, diarrhea, mucosal inflammation), hematologic toxicity, and skin toxicity (e.g., hand and foot syndrome, rash, pruritus) in patients also receiving OAT1 and OAT3 inhibitors.
Isoniazid, INH; Pyrazinamide, PZA; Rifampin: (Moderate) Avoid coadministration of rifampin and cefazolin in patients at increased risk of bleeding. If no alternative treatment options are available, closely monitor prothrombin time and other coagulation tests, and administer vitamin K as indicated. Postmarketing reports suggest that concomitant administration of high doses of rifampin and cefazolin may prolong the prothrombin time, leading to severe vitamin K-dependent coagulation disorders that may be life-threatening or fatal.
Isoniazid, INH; Rifampin: (Moderate) Avoid coadministration of rifampin and cefazolin in patients at increased risk of bleeding. If no alternative treatment options are available, closely monitor prothrombin time and other coagulation tests, and administer vitamin K as indicated. Postmarketing reports suggest that concomitant administration of high doses of rifampin and cefazolin may prolong the prothrombin time, leading to severe vitamin K-dependent coagulation disorders that may be life-threatening or fatal.
Loop diuretics: (Minor) Nephrotoxicity associated with cephalosporins may be potentiated by concomitant therapy with loop diuretics. Clinicians should be aware that this may occur even in patients with minor or transient renal impairment.
Oral Contraceptives: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available.
Rifampin: (Moderate) Avoid coadministration of rifampin and cefazolin in patients at increased risk of bleeding. If no alternative treatment options are available, closely monitor prothrombin time and other coagulation tests, and administer vitamin K as indicated. Postmarketing reports suggest that concomitant administration of high doses of rifampin and cefazolin may prolong the prothrombin time, leading to severe vitamin K-dependent coagulation disorders that may be life-threatening or fatal.
Sodium picosulfate; Magnesium oxide; Anhydrous citric acid: (Major) Prior or concomitant use of antibiotics with sodium picosulfate; magnesium oxide; anhydrous citric acid may reduce efficacy of the bowel preparation as conversion of sodium picosulfate to its active metabolite bis-(p-hydroxy-phenyl)-pyridyl-2-methane (BHPM) is mediated by colonic bacteria. If possible, avoid coadministration. Certain antibiotics (i.e., tetracyclines and quinolones) may chelate with the magnesium in sodium picosulfate; magnesium oxide; anhydrous citric acid solution. Therefore, these antibiotics should be taken at least 2 hours before and not less than 6 hours after the administration of sodium picosulfate; magnesium oxide; anhydrous citric acid solution.
Warfarin: (Moderate) The concomitant use of warfarin with many classes of antibiotics, including cephalosporins, may increase the INR thereby potentiating the risk for bleeding. Inhibition of vitamin K synthesis due to alterations in the intestinal flora may be a mechanism; however, concurrent infection is also a potential risk factor for elevated INR. Additionally, certain cephalosporins (cefotetan, cefoperazone, cefamandole) are associated with prolongation of the prothrombin time due to the methylthiotetrazole (MTT) side chain at the R2 position, which disturbs the synthesis of vitamin K-dependent clotting factors in the liver. Monitor patients for signs and symptoms of bleeding. Additionally, increased monitoring of the INR, especially during initiation and upon discontinuation of the antibiotic, may be necessary.

Ancef/Cefazolin/Cefazolin Sodium Intravenous Inj Sol: 1mL, 20mg
Ancef/Cefazolin/Cefazolin Sodium/Kefzol Intramuscular Inj Pwd F/Sol: 1g, 2g, 10g, 20g, 500mg
Ancef/Cefazolin/Cefazolin Sodium/Kefzol Intravenous Inj Pwd F/Sol: 1g, 2g, 10g, 20g, 300g, 500mg
Cefazolin/Cefazolin Sodium Intravenous Inj Pwd: 2g, 3g

12 g/day IV/IM.

12 g/day IV/IM.

100 mg/kg/day (Max: 6 g/day) IV/IM for most indications; however, doses up to 150 mg/kg/day (Max: 12 g/day) IV have been used off-label.

100 mg/kg/day (Max: 6 g/day) IV/IM for most indications; however, doses up to 150 mg/kg/day (Max: 12 g/day) IV have been used off-label.

100 mg/kg/day IV/IM for most indications; however, doses up to 150 mg/kg/day IV have been used off-label.

32 weeks gestation and older and 8 days and older: Safety and efficacy have not been established; however, doses up to 150 mg/kg/day IV/IM have been used off-label.
32 weeks gestation and older and 0 to 7 days: Safety and efficacy have not been established; however, doses up to 100 mg/kg/day IV/IM have been used off-label.
younger than 32 weeks gestation and 7 days and older: Safety and efficacy have not been established; however, doses up to 75 mg/kg/day IV/IM have been used off-label.
younger than 32 weeks gestation and 0 to 6 days: Safety and efficacy have not been established; however, doses up to 50 mg/kg/day IV/IM have been used off-label.

Cefazolin, a beta-lactam antibiotic similar to penicillins, inhibits the third and final stage of bacterial cell wall synthesis by preferentially binding to specific penicillin-binding proteins (PBPs) that are located inside the bacterial cell wall. Penicillin-binding proteins are responsible for several steps in the synthesis of the cell wall and are found in quantities of several hundred to several thousand molecules per bacterial cell. Penicillin-binding proteins vary among different bacterial species. Thus, the intrinsic activity of cefazolin as well as other cephalosporins and penicillins against a particular organism depends on their ability to gain access to and bind with the necessary PBP. Like all beta-lactam antibiotics, cefazolin's ability to interfere with PBP-mediated cell wall synthesis ultimately leads to cell lysis. Lysis is mediated by bacterial cell wall autolytic enzymes (i.e., autolysins). The relationship between PBPs and autolysins is unclear, but it is possible that the beta-lactam antibiotic interferes with an autolysin inhibitor.
 
Beta-lactams, including cefazolin, exhibit concentration-independent or time-dependent killing. In vitro and in vivo animal studies have demonstrated that the major pharmacodynamic parameter that determines efficacy for beta-lactams is the amount of time free (non-protein bound) drug concentrations exceed the minimum inhibitory concentration (MIC) of the organism (free T above the MIC). This microbiological killing pattern is due to the mechanism of action, which is acylation of PBPs. There is a maximum proportion of PBPs that can be acylated; therefore, once maximum acylation has occurred, killing rates cannot increase. Free beta-lactam concentrations do not have to remain above the MIC for the entire dosing interval. The percentage of time required for both bacteriostatic and maximal bactericidal activity is different for the various classes of beta-lactams. Cephalosporins require free drug concentrations to be above the MIC for 35% to 40% of the dosing interval for bacteriostatic activity and 60% to 70% of the dosing interval for bactericidal activity.
 
The susceptibility interpretive criteria for cefazolin are delineated by pathogen. The MICs are defined for Enterobacterales as susceptible at 2 or less mcg/mL or less, intermediate at 4 mcg/mL, and resistant at 8 mcg/mL or more for infections other than uncomplicated urinary tract infections (UTIs) due to E. coli, K. pneumoniae, and P. mirabilis (based on a dosage regimen of 2 g IV every 8 hours) and susceptible at 16 mcg/mL or less and resistant at 32 mcg/mL or more for uncomplicated UTIs due to E. coli, K. pneumoniae, and P. mirabilis (based on a dosage regimen of 1 g IV every 12 hours); however, the FDA does not recognize separate susceptibility test interpretive criteria for uncomplicated UTIs. The MICs are defined for Vibrio sp. (excluding V. cholerae) as susceptible at 2 or less mcg/mL or less, intermediate at 4 mcg/mL, and resistant at 8 mcg/mL or more (based on a dosage regimen of 2 g IV every 8 hours). Penicillin-susceptible beta-hemolytic streptococci and methicillin-susceptible staphylococci can be considered susceptible to cefazolin.
 
The predominant mechanisms of resistance include the presence of extended-spectrum beta-lactamases and enzymatic hydrolysis.

Cefazolin is administered intravenously and intramuscularly. Approximately 80% of circulating drug is protein-bound. It is widely distributed into most body tissues and fluids; however, cefazolin does not reach therapeutic concentrations within the CSF. The drug concentrates in the urine at concentrations much higher than peak serum concentrations. Bile concentrations in patients without obstructive biliary disease can reach or exceed serum concentrations by up to 5 times; however, in patients with obstructive biliary disease, bile concentrations of cefazolin are considerably lower than serum concentrations (less than 1 mcg/mL). In synovial fluid, the cefazolin concentration becomes comparable to that reached in the serum at about 4 hours after drug administration. Cefazolin is not hepatically metabolized. Cefazolin is largely excreted unchanged into the urine with approximately 60% excreted within the first 6 hours, reaching 70% to 80% within the first 24 hours. In non-neonatal patients, including adults, with normal renal function, the elimination half-life is approximately 1.8 hours after IV administration and 2 hours after IM administration.
 
Affected cytochrome P450 isoenzymes and drug transporters: none

Studies have shown that after IV administration of cefazolin to normal adult volunteers, mean serum concentrations peaked at 185 mcg/mL and were approximately 4 mcg/mL at 8 hours after a 1 g dose. After a single 2 g dose, the mean Tmax was 0.25 hours and mean Cmax was 280.9 mcg/mL. In a study of constant IV infusion of 3.5 mg/kg for 1 hour and 1.5 mg/kg for the next 2 hours in healthy volunteers, serum concentrations at the third hour were approximately 28 mcg/mL. Studies in hospitalized patients with infections indicate that cefazolin mean peak serum concentrations were approximately equivalent to those seen in healthy volunteers. When given as a slow IV push over 2 to 3 minutes, peak concentrations are achieved approximately 15 minutes after administration.

Peak serum concentrations of cefazolin occur within 1 hour after an intramuscular (IM) dose. After IM administration of cefazolin to normal adult volunteers, the mean serum concentrations were 37 mcg/mL at 1 hour after a 500 mg dose, and 64 mcg/mL at 1 hour after a 1 g dose.

While available studies cannot definitively establish the absence of risk, available data over several decades with cephalosporin use, including cefazolin, in human pregnancy have not established a drug-associated risk of major birth defects, miscarriage, or adverse maternal or fetal outcomes. These studies have methodologic limitations, including small sample size, retrospective data collection, and inconsistent comparator groups. Cefazolin crosses the placenta. Animal reproduction studies with cefazolin during organogenesis at doses 1 to 3 times the maximum recommended human dose (MRHD) did not demonstrate adverse developmental outcomes.

Data from published literature report that cefazolin is present in human milk, but is not expected to accumulate in the breast-feeding infant. There are no data on the effects of cefazolin on the breast-fed child or on milk production. Previous American Academy of Pediatrics (AAP) recommendations considered cefazolin as generally compatible with breast-feeding.[27500]