Ampicillin injection

Usual Adult Dose for Bacterial Infection:

The manufacturer recommends:
Parenteral:
-Infections of the respiratory tract and soft tissues: 250 to 500 mg IM or IV every 6 hours
-Infections of the gastrointestinal and genitourinary tracts (including Neisseria gonorrhoeae infections in females): 500 mg IM or IV every 6 hours
-Urethritis in males due to N gonorrhoeae: 500 mg IM or IV every 8 to 12 hours for 2 doses
-Bacterial meningitis: 150 to 200 mg/kg/day in equally divided doses every 3 to 4 hours; may start with IV drip therapy and continue with IM injections
-Septicemia: 150 to 200 mg/kg/day; start with IV administration for at least 3 days and continue with IM route every 3 to 4 hours

Oral:
-Genitourinary or gastrointestinal tract infections (other than gonorrhea): 500 mg orally every 6 hours
-Gonorrhea: 3.5 g orally as a single dose (plus probenecid 1 g)
-Respiratory tract infections: 250 mg orally every 6 hours

Approved indications:
-Parenteral: Respiratory tract Infections, bacterial meningitis, septicemia, endocarditis, urinary tract infections, gastrointestinal infections
-Oral: Genitourinary tract infections (including gonorrhea), respiratory tract infections, gastrointestinal tract infections, and meningitis

Some experts recommend:
Parenteral: 1 to 2 g IM or IV every 4 to 6 hours or 50 to 250 mg/kg/day IM or IV in divided doses
Maximum dose: 12 g/day

Oral: 250 to 500 mg orally every 6 hours

Usual Adult Dose for Endocarditis:

The manufacturer gives no specific dosing instructions.

Approved indications:
-Parenteral: Endocarditis due to susceptible gram-positive organisms including Streptococcus species, penicillin G-susceptible staphylococci, and enterococci

American Heart Association (AHA) recommendations for patients with normal renal function:
Native valve or prosthetic valve infections due to susceptible enterococci: Ampicillin 2 g IV every 4 hours plus gentamicin or streptomycin (if gentamicin resistant)

Duration of therapy:
-Native valve: 4 weeks (symptoms for less than 3 months) or 6 weeks (symptoms for at least 3 months)
-Prosthetic valve: At least 6 weeks

Native valve or prosthetic valve infections due to Enterococcus faecalis strains resistant to penicillin, aminoglycoside, and vancomycin: Ampicillin 2 g IV every 4 hours plus imipenem-cilastatin or ceftriaxone
Duration of therapy: At least 8 weeks

Infections due to susceptible strains of Escherichia coli or Proteus mirabilis: Ampicillin 2 g IV every 4 hours plus an aminoglycoside (usually gentamicin)

Usual Adult Dose for Bacterial Endocarditis Prophylaxis:

(Not approved by FDA)

AHA recommendations: 2 g IM or IV as a single dose 30 to 60 minutes before procedure

Comments:
-Recommended for patients unable to take oral medication.
-Antibiotic prophylaxis may be used for dental procedures (involving manipulation of gingival tissues or periapical region of teeth or perforation of oral mucosa), respiratory tract procedures, or procedures on infected skin, skin structures, or musculoskeletal tissue only for patients with the highest risk of infective endocarditis.

Usual Adult Dose for Meningitis:

The manufacturer recommends: 150 to 200 mg/kg/day IV in equally divided doses every 3 to 4 hours

Comments:
-Therapy may be started with IV administration and continued with IM injections.

Approved indications:
-Parenteral: Bacterial meningitis due to E coli, group B streptococci, and other gram-negative bacteria (Listeria monocytogenes, N meningitidis)
-Oral: Meningitis due to N meningitidis

Some experts recommend:
IV: 200 mg/kg/day IV in equally divided doses every 4 hours, in combination with other parenteral antibiotics
Maximum dose: 12 g/day

Intrathecal or intraventricular: 10 to 50 mg/day in addition to IV antibiotics

Usual Adult Dose for Septicemia:

The manufacturer recommends: 150 to 200 mg/kg/day

Comments:
-Start with IV administration for at least 3 days and continue with the IM route every 3 to 4 hours

Approved indications:
-Parenteral: Septicemia due to susceptible gram-positive organisms including Streptococcus species, penicillin G-susceptible staphylococci, and enterococci; gram-negative sepsis due to E coli, P mirabilis, and Salmonella species

Some experts recommend: 1 to 2 g IV every 3 to 4 hours, in combination with other antibiotics

Usual Adult Dose for Gastroenteritis:

The manufacturer recommends: 500 mg orally or IM or IV every 6 hours

Comments:
-Severe, chronic, or stubborn infections may require larger doses.

Approved indications:
-Parenteral: Gastrointestinal infections due to Salmonella species (including S typhi) and Shigella species
-Oral: Gastrointestinal tract infections due to Shigella, Salmonella species (including S typhi), E coli, P mirabilis, and enterococci

Some experts recommend: 250 to 500 mg orally every 6 hours

Usual Adult Dose for Intraabdominal Infection:

The manufacturer recommends: 500 mg orally or IM or IV every 6 hours

Comments:
-Severe, chronic, or stubborn infections may require larger doses.

Approved indications:
-Parenteral: Gastrointestinal infections due to Salmonella species (including S typhi) and Shigella species
-Oral: Gastrointestinal tract infections due to Shigella, Salmonella species (including S typhi), E coli, P mirabilis, and enterococci

Some experts recommend: 1 to 2 g IV every 4 to 6 hours in combination with other antibiotics, depending on the nature and severity of the infection
Duration of therapy: 10 to 14 days

Usual Adult Dose for Skin or Soft Tissue Infection:

The manufacturer recommends: 250 to 500 mg IM or IV every 6 hours
Some experts recommend: 250 to 500 mg orally every 6 hours or 1 to 2 g IV every 4 to 6 hours, depending on the nature and severity of the infection

Usual Adult Dose for Pharyngitis:

The manufacturer recommends:
Parenteral: 250 to 500 mg IM or IV every 6 hours
Oral: 250 mg orally every 6 hours

Approved indications:
Parenteral: Respiratory tract infections due to Streptococcus pneumoniae, Staphylococcus aureus, Haemophilus influenzae, and Group A beta-hemolytic streptococci
Oral: Respiratory tract infections due to nonpenicillinase-producing H influenzae and staphylococci, and streptococci (including S pneumoniae)

Some experts recommend: 500 mg orally or 1 to 2 g IM or IV every 6 hours, depending on the nature and severity of the infection

Usual Adult Dose for Sinusitis:

The manufacturer recommends:
Parenteral: 250 to 500 mg IM or IV every 6 hours
Oral: 250 mg orally every 6 hours

Approved indications:
Parenteral: Respiratory tract infections due to Streptococcus pneumoniae, Staphylococcus aureus, Haemophilus influenzae, and Group A beta-hemolytic streptococci
Oral: Respiratory tract infections due to nonpenicillinase-producing H influenzae and staphylococci, and streptococci (including S pneumoniae)

Some experts recommend: 500 mg orally or 1 to 2 g IM or IV every 6 hours, depending on the nature and severity of the infection

Usual Adult Dose for Upper Respiratory Tract Infection:

The manufacturer recommends:
Parenteral: 250 to 500 mg IM or IV every 6 hours
Oral: 250 mg orally every 6 hours

Approved indications:
Parenteral: Respiratory tract infections due to Streptococcus pneumoniae, Staphylococcus aureus, Haemophilus influenzae, and Group A beta-hemolytic streptococci
Oral: Respiratory tract infections due to nonpenicillinase-producing H influenzae and staphylococci, and streptococci (including S pneumoniae)

Some experts recommend: 500 mg orally or 1 to 2 g IM or IV every 6 hours, depending on the nature and severity of the infection

Usual Adult Dose for Pneumonia:

The manufacturer recommends:
Parenteral: 250 to 500 mg IM or IV every 6 hours
Oral: 250 mg orally every 6 hours

Approved indications:
Parenteral: Respiratory tract infections due to S pneumoniae, S aureus, H influenzae, and Group A beta-hemolytic streptococci
Oral: Respiratory tract infections due to nonpenicillinase-producing H influenzae and staphylococci, and streptococci (including S pneumoniae)

Some experts recommend:
Beta-lactamase negative, penicillin-susceptible: 1 to 2 g IV every 4 to 6 hours, in combination with other antibiotic(s) depending on the nature and severity of the infection

Usual Adult Dose for Bronchitis:

The manufacturer recommends:
Parenteral: 250 to 500 mg IM or IV every 6 hours
Oral: 250 mg orally every 6 hours

Approved indications:
Parenteral: Respiratory tract infections due to S pneumoniae, S aureus, H influenzae, and Group A beta-hemolytic streptococci
Oral: Respiratory tract infections due to nonpenicillinase-producing H influenzae and staphylococci, and streptococci (including S pneumoniae)

Some experts recommend:
Bacterial exacerbations of chronic bronchitis: 250 to 500 mg orally every 6 hours for 5 to 10 days, depending on the nature and severity of the infection

Usual Adult Dose for Urinary Tract Infection:

The manufacturer recommends: 500 mg orally or IM or IV every 6 hours

Comments:
-Severe, chronic, or stubborn infections may require larger doses.

Approved indications:
-Parenteral: Urinary tract infections due to sensitive strains of E coli and P mirabilis
-Oral: Genitourinary tract infections due to E coli, P mirabilis, enterococci, Shigella, Salmonella species (including S typhi)

Some experts recommend:
Mild, uncomplicated: 250 to 500 mg orally every 6 hours
Severe, complicated: 500 mg to 2 g IV every 4 to 6 hours with or without other antibiotics, depending on the nature and severity of the infection

Usual Adult Dose for Pyelonephritis:

The manufacturer recommends: 500 mg orally or IM or IV every 6 hours

Comments:
-Severe, chronic, or stubborn infections may require larger doses.

Approved indications:
-Parenteral: Urinary tract infections due to sensitive strains of E coli and P mirabilis
-Oral: Genitourinary tract infections due to E coli, P mirabilis, enterococci, Shigella, Salmonella species (including S typhi)

Some experts recommend: 500 mg to 2 g IM or IV every 4 to 6 hours with or without other antibiotics, depending on the nature and severity of the infection
Duration of therapy: 2 to 3 weeks

Usual Adult Dose for Shigellosis:

The manufacturer recommends: 500 mg orally or IM or IV every 6 hours

Comments:
-Severe, chronic, or stubborn infections may require larger doses.

Approved indications: Gastrointestinal tract infections due to Shigella species

Some experts recommend: 500 mg orally every 6 hours for 5 days

Usual Adult Dose for Typhoid Fever:

The manufacturer recommends: 500 mg orally or IM or IV every 6 hours

Comments:
-Severe, chronic, or stubborn infections may require larger doses.

Approved indications: Gastrointestinal tract infections due to Salmonella species (including S typhi)

Some experts recommend:
Severe, fully susceptible: 25 mg/kg IM or IV every 6 hours for 10 to 14 days
Carrier state: 1.5 g orally or IV with probenecid 500 mg every 6 hours for 6 weeks

Comments:
-Fluoroquinolones or amoxicillin are considered the drugs of choice.

Usual Adult Dose for Prevention of Perinatal Group B Streptococcal Disease:

(Not approved by FDA)

Centers for Disease Control and Prevention (CDC) recommendations: 2 g IV initial dose, then 1 g IV every 4 hours until delivery

Comments:
-Ampicillin is recommended as an alternative to penicillin G.

Usual Adult Dose for Surgical Prophylaxis:

(Not approved by FDA)

Liver transplant: Ampicillin 1 g IV plus cefotaxime 1 g IV at induction of anesthesia, then every 6 hours during procedure and for 48 hours after final surgical closure

Usual Adult Dose for Leptospirosis:

(Not approved by FDA)

Some experts recommend:
Mild: 500 to 750 mg orally every 6 hours
Moderate to severe: 0.5 to 1 g IV every 6 hours

Usual Adult Dose for Peritonitis:

(Not approved by FDA)

Some experts recommend:
CAPD-associated peritonitis: 250 to 500 mg orally twice a day and/or 100 to 125 mg/L exchange intraperitoneally, with or without other antibiotics depending on the nature and severity of the infection
Secondary: 1 to 2 g IV every 4 to 6 hours in combination with other antibiotics, depending on the nature and severity of the infection
Duration of therapy: 10 to 14 days

Usual Adult Dose for Otitis Media:

(Not approved by FDA)

Some experts recommend: 500 mg orally or 1 to 2 g IM or IV every 6 hours, depending on the nature and severity of the infection

Usual Pediatric Dose for Bacterial Infection:

American Academy of Pediatrics (AAP) General Dosing Recommendations for Susceptible Infections:
Neonates:
7 days or less, 2000 g or less: 50 mg/kg IM or IV every 12 hours
7 days or less, greater than 2000 g: 50 mg/kg IM or IV every 8 hours
8 to 28 days, 2000 g or less: 50 mg/kg IM or IV every 8 hours
8 to 28 days, greater than 2000 g: 50 mg/kg IM or IV every 6 hours

1 month or older:
Mild to moderate infections:
Parenteral: 25 to 37.5 mg/kg IM or IV every 6 hours
Oral: 12.5 to 25 mg/kg orally every 6 hours
Maximum dose: 4 g/day

Severe infections: 50 to 100 mg/kg IM or IV every 6 hours
Maximum dose: 12 g/day

The Manufacturer Recommends:
Parenteral:
-Infections of the respiratory tract and soft tissues:
Less than 40 kg: 25 to 50 mg/kg/day IM or IV in equally divided doses every 6 to 8 hours
40 kg or more: 250 to 500 mg IM or IV every 6 hours

-Infections of the gastrointestinal and genitourinary tracts (including N gonorrhoeae infections in females):
Less than 40 kg: 50 mg/kg/day IM or IV in equally divided doses every 6 to 8 hours
40 kg or more: 500 mg IM or IV every 6 hours

-Bacterial meningitis:
Children: 150 to 200 mg/kg/day in equally divided doses every 3 to 4 hours; may start with IV drip therapy and continue with IM injections

-Septicemia:
Children: 150 to 200 mg/kg/day; start with IV administration for at least 3 days and continue with IM route every 3 to 4 hours

Oral:
-Genitourinary or gastrointestinal tract infections:
20 kg or less: 25 mg/kg orally every 6 hours
Greater than 20 kg: 500 mg orally every 6 hours

-Respiratory tract infections:
20 kg or less: 50 mg/kg/day orally in equally divided doses every 6 to 8 hours
Greater than 20 kg: 250 mg orally every 6 hours

Comments:
-Pediatric doses should not exceed recommended adult doses.

Approved indications:
-Parenteral: Respiratory tract Infections, bacterial meningitis, septicemia, endocarditis, urinary tract infections, gastrointestinal infections
-Oral: Genitourinary tract infections (including gonorrhea), respiratory tract infections, gastrointestinal tract infections, and meningitis

Usual Pediatric Dose for Bacteremia:

AAP Recommendations:
Group B streptococcal bacteremia (presumed or proven):
Neonates:
7 days or younger, 2000 g or less: 100 mg/kg IM or IV every 12 hours
7 days or younger, greater than 2000 g: 50 mg/kg IM or IV every 8 hours or 100 mg/kg IM or IV every 12 hours
8 to 28 days, 2000 g or less: 50 mg/kg IM or IV every 8 hours
8 to 28 days, greater than 2000 g: 50 mg/kg IM or IV every 6 hours

Duration of therapy: At least 10 days for treatment of bacteremia without defined focus

The Manufacturer Recommends:
Children: 150 to 200 mg/kg/day

Comments:
-Start with IV administration for at least 3 days and continue with the IM route every 3 to 4 hours

Approved indications:
-Parenteral: Septicemia due to susceptible gram-positive organisms including Streptococcus species, penicillin G-susceptible staphylococci, and enterococci; gram-negative sepsis due to E coli, P mirabilis, and Salmonella species

Usual Pediatric Dose for Septicemia:

AAP Recommendations:
Group B streptococcal bacteremia (presumed or proven):
Neonates:
7 days or younger, 2000 g or less: 100 mg/kg IM or IV every 12 hours
7 days or younger, greater than 2000 g: 50 mg/kg IM or IV every 8 hours or 100 mg/kg IM or IV every 12 hours
8 to 28 days, 2000 g or less: 50 mg/kg IM or IV every 8 hours
8 to 28 days, greater than 2000 g: 50 mg/kg IM or IV every 6 hours

Duration of therapy: At least 10 days for treatment of bacteremia without defined focus

The Manufacturer Recommends:
Children: 150 to 200 mg/kg/day

Comments:
-Start with IV administration for at least 3 days and continue with the IM route every 3 to 4 hours

Approved indications:
-Parenteral: Septicemia due to susceptible gram-positive organisms including Streptococcus species, penicillin G-susceptible staphylococci, and enterococci; gram-negative sepsis due to E coli, P mirabilis, and Salmonella species

Usual Pediatric Dose for Meningitis:

AAP Recommendations:
Neonates:
Group B streptococcal meningitis:
7 days or younger: 50 to 100 mg/kg IV every 8 hours; some experts recommend 75 mg/kg IV every 6 hours
Older than 7 days: 50 to 75 mg/kg IV every 6 hours

Duration of therapy: At least 14 days (if uncomplicated)

Infants, children, adolescents: 50 to 100 mg/kg IV every 6 hours
Maximum dose: 12 g/day

The Manufacturer Recommends:
Children: 150 to 200 mg/kg/day IV in equally divided doses every 3 to 4 hours

Comments:
-Therapy may be started with IV administration and continued with IM injections.

Approved indications:
-Parenteral: Bacterial meningitis due to E coli, group B streptococci, and other gram-negative bacteria (L monocytogenes, N meningitidis)
-Oral: Meningitis due to N meningitidis

Usual Pediatric Dose for Endocarditis:

The manufacturer gives no specific dosing instructions.

Approved indications:
-Parenteral: Endocarditis due to susceptible gram-positive organisms including Streptococcus species, penicillin G-susceptible staphylococci, and enterococci

AHA Recommendations for Patients with Normal Renal Function (dosage should not exceed adult dose):
Native valve or prosthetic valve infections due to susceptible enterococci: Ampicillin 300 mg/kg/day IV in equally divided doses every 4 to 6 hours plus gentamicin or streptomycin (if gentamicin resistant)
Maximum dose: 12 g/day

Duration of therapy:
-Native valve: 4 weeks (symptoms for less than 3 months) or 6 weeks (symptoms for at least 3 months)
-Prosthetic valve: At least 6 weeks

Native valve or prosthetic valve infections due to E faecalis strains resistant to penicillin, aminoglycoside, and vancomycin: Ampicillin 300 mg/kg/day IV in equally divided doses every 4 to 6 hours plus imipenem-cilastatin or ceftriaxone
Duration of therapy: At least 8 weeks

Usual Pediatric Dose for Bacterial Endocarditis Prophylaxis:

(Not approved by FDA)

AHA Recommendations:
Children: 50 mg/kg IM or IV as a single dose 30 to 60 minutes before procedure

Comments:
-Recommended for patients unable to take oral medication.
-Antibiotic prophylaxis may be used for dental procedures (involving manipulation of gingival tissues or periapical region of teeth or perforation of oral mucosa), respiratory tract procedures, or procedures on infected skin, skin structures, or musculoskeletal tissue only for patients with the highest risk of infective endocarditis.

Usual Pediatric Dose for Upper Respiratory Tract Infection:

AAP General Dosing Recommendations for Susceptible Infections:
Neonates:
7 days or less, 2000 g or less: 50 mg/kg IM or IV every 12 hours
7 days or less, greater than 2000 g: 50 mg/kg IM or IV every 8 hours
8 to 28 days, 2000 g or less: 50 mg/kg IM or IV every 8 hours
8 to 28 days, greater than 2000 g: 50 mg/kg IM or IV every 6 hours

1 month or older:
Mild to moderate infections:
Parenteral: 25 to 37.5 mg/kg IM or IV every 6 hours
Oral: 12.5 to 25 mg/kg orally every 6 hours
Maximum dose: 4 g/day

Severe infections: 50 to 100 mg/kg IM or IV every 6 hours
Maximum dose: 12 g/day

The Manufacturer Recommends:
Parenteral:
Less than 40 kg: 25 to 50 mg/kg/day IM or IV in equally divided doses every 6 to 8 hours
40 kg or more: 250 to 500 mg IM or IV every 6 hours

Oral:
20 kg or less: 50 mg/kg/day orally in equally divided doses every 6 to 8 hours
Greater than 20 kg: 250 mg orally every 6 hours

Comments:
-Pediatric doses should not exceed recommended adult doses.

Approved indications:
-Parenteral: Respiratory tract infections due to S pneumoniae, S aureus (penicillinase and nonpenicillinase-producing), H influenzae, and group A beta-hemolytic streptococci
-Oral: Respiratory tract infections due to nonpenicillinase-producing H influenzae and staphylococci, and streptococci (including S pneumoniae)

Usual Pediatric Dose for Pneumonia:

AAP General Dosing Recommendations for Susceptible Infections:
Neonates:
7 days or less, 2000 g or less: 50 mg/kg IM or IV every 12 hours
7 days or less, greater than 2000 g: 50 mg/kg IM or IV every 8 hours
8 to 28 days, 2000 g or less: 50 mg/kg IM or IV every 8 hours
8 to 28 days, greater than 2000 g: 50 mg/kg IM or IV every 6 hours

1 month or older:
Mild to moderate infections:
Parenteral: 25 to 37.5 mg/kg IM or IV every 6 hours
Oral: 12.5 to 25 mg/kg orally every 6 hours
Maximum dose: 4 g/day

Severe infections: 50 to 100 mg/kg IM or IV every 6 hours
Maximum dose: 12 g/day

Infectious Diseases Society of America (IDSA) and Pediatric Infectious Diseases Society (PIDS) Recommendations:
Community-acquired pneumonia:
Older than 3 months:
Empiric therapy, S pneumoniae (MICs for penicillin 2 mcg/mL or greater), or H influenzae (beta-lactamase negative) in fully immunized patients: 37.5 to 50 mg/kg IV every 6 hours
Group A Streptococcus: 50 mg/kg IV every 6 hours
S pneumoniae resistant to penicillin (MICs 4 mcg/mL or greater): 75 to 100 mg/kg IV every 6 hours; recommended as alternate therapy

The Manufacturer Recommends:
Parenteral:
Less than 40 kg: 25 to 50 mg/kg/day IM or IV in equally divided doses every 6 to 8 hours
40 kg or more: 250 to 500 mg IM or IV every 6 hours

Oral:
20 kg or less: 50 mg/kg/day orally in equally divided doses every 6 to 8 hours
Greater than 20 kg: 250 mg orally every 6 hours

Comments:
-Pediatric doses should not exceed recommended adult doses.

Approved indications:
-Parenteral: Respiratory tract infections due to S pneumoniae, S aureus (penicillinase and nonpenicillinase-producing), H influenzae, and group A beta-hemolytic streptococci
-Oral: Respiratory tract infections due to nonpenicillinase-producing H influenzae and staphylococci, and streptococci (including S pneumoniae)

Usual Pediatric Dose for Skin or Soft Tissue Infection:

AAP General Dosing Recommendations for Susceptible Infections:
Neonates:
7 days or less, 2000 g or less: 50 mg/kg IM or IV every 12 hours
7 days or less, greater than 2000 g: 50 mg/kg IM or IV every 8 hours
8 to 28 days, 2000 g or less: 50 mg/kg IM or IV every 8 hours
8 to 28 days, greater than 2000 g: 50 mg/kg IM or IV every 6 hours

1 month or older:
Mild to moderate infections:
Parenteral: 25 to 37.5 mg/kg IM or IV every 6 hours
Oral: 12.5 to 25 mg/kg orally every 6 hours
Maximum dose: 4 g/day

Severe infections: 50 to 100 mg/kg IM or IV every 6 hours
Maximum dose: 12 g/day

The Manufacturer Recommends:
Parenteral:
Less than 40 kg: 25 to 50 mg/kg/day IM or IV in equally divided doses every 6 to 8 hours
40 kg or more: 250 to 500 mg IM or IV every 6 hours

Comments:
-Pediatric doses should not exceed recommended adult doses.

Usual Pediatric Dose for Urinary Tract Infection:

AAP General Dosing Recommendations for Susceptible Infections:
Neonates:
7 days or less, 2000 g or less: 50 mg/kg IM or IV every 12 hours
7 days or less, greater than 2000 g: 50 mg/kg IM or IV every 8 hours
8 to 28 days, 2000 g or less: 50 mg/kg IM or IV every 8 hours
8 to 28 days, greater than 2000 g: 50 mg/kg IM or IV every 6 hours

1 month or older:
Mild to moderate infections:
Parenteral: 25 to 37.5 mg/kg IM or IV every 6 hours
Oral: 12.5 to 25 mg/kg orally every 6 hours
Maximum dose: 4 g/day

Severe infections: 50 to 100 mg/kg IM or IV every 6 hours
Maximum dose: 12 g/day

The Manufacturer Recommends:
Parenteral:
Less than 40 kg: 50 mg/kg/day IM or IV in equally divided doses every 6 to 8 hours
40 kg or more: 500 mg IM or IV every 6 hours

Oral:
20 kg or less: 25 mg/kg orally every 6 hours
Greater than 20 kg: 500 mg orally every 6 hours

Comments:
-Pediatric doses should not exceed recommended adult doses.
-Severe, chronic, or stubborn infections may require larger doses.

Approved indications:
-Parenteral: Urinary tract infections due to sensitive strains of E coli and P mirabilis
-Oral: Genitourinary tract infections due to E coli, P mirabilis, enterococci, Shigella, Salmonella species (including S typhi)

Usual Pediatric Dose for Surgical Prophylaxis:

(Not approved by FDA)

Some experts recommend:
Liver transplant:
1 month or older: Ampicillin 50 mg/kg IV plus cefotaxime 50 mg/kg IV at induction of anesthesia and every 6 hours for 48 hours after final surgical closure