III. Contraindications

  1. Penicillin Allergy
    1. Cephalexin and Cefaclor have similar side chains and risk of cross reactivity with Ampicillin

IV. Dosing

  1. Adult (or child with weight >40 kg)
    1. Mild/Moderate Infections (typical dose): 1 to 2 g IV every 4 to 6 hours
    2. Severe Infections (Sepsis, Meningitis): 150 to 200 mg/kg/day IV divided every 4 hours
  2. Child (weight <40 kg)
    1. Mild/Moderate Infections (typical dose): 100 to 150 mg/kg/day IM or IV divided every 6 hours
    2. Severe Infections (Sepsis, Meningitis): 200 to 400 mg/kg/day IM or IV divided every 6 hours
    3. Newborns (weight >2 kg): 25 to 50 mg/kg IV every 8 hours until age >1 week, then every 6 hours
  3. Renal Dosing
    1. eGFR 30 to 50 ml/min: Dose every 6 to 8 hours
    2. eGFR 10 to 30 ml/min: Dose every 8 to 12 hours
    3. eGFR <10 ml/min: Dose every 12 to 24 hours (after Hemodialysis)

V. Mechanism

VI. Adverse Effects

  1. See Aminopenicillin
  2. See Penicillin
  3. Maculopapular rash
    1. Onset 5-7 days after initiating medication
    2. Typically not IgE mediated (non-allergic)
      1. No immediate allergy (e.g. Urticaria), systemic symptoms or mucous membrane involvement
    3. Typically safe to use Amoxicillin in future if non-allergic rash alone
      1. Consider IgE Skin Testing if unclear rash etiology
    4. References
      1. Orman and Hayes in Herbert (2017) EM:Rap 17(7): 7-8
  4. Diarrhea
    1. More common with Augmentin
    2. Modifications can decrease stools
      1. Dose exactly by kilogram for children
      2. Avoid food before dose
      3. Consider eating yogurt with each dose

VII. Safety

  1. Pregnancy Category B
  2. Safe in Lactation

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Cost: Medications

ampicillin (on 12/21/2022 at Medicaid.Gov Survey of pharmacy drug pricing)
AMPICILLIN 500 MG CAPSULE Generic $0.48 each

Ontology: Ampicillin (C0002680)

Definition (NCI) A broad-spectrum, semi-synthetic, beta-lactam penicillin antibiotic with bactericidal activity. Ampicillin binds to and inactivates penicillin-binding proteins (PBP) located on the inner membrane of the bacterial cell wall. Inactivation of PBPs interferes with the cross-linkage of peptidoglycan chains necessary for bacterial cell wall strength and rigidity. This interrupts bacterial cell wall synthesis and results in the weakening of the bacterial cell wall and causes cell lysis. Ampicillin is stable against hydrolysis by a variety of beta-lactamases, therefore, can be used in wide range of gram-positive and -negative infections.
Definition (MSH) Semi-synthetic derivative of penicillin that functions as an orally active broad-spectrum antibiotic.
Definition (CSP) semi-synthetic derivative of penicillin that functions as an orally active broad-spectrum antibiotic.
Concepts Antibiotic (T195) , Organic Chemical (T109)
MSH D000667
SnomedCT 31087008, 387170002
LNC LP15762-5, MTHU007962
English Aminobenzyl Penicillin, Aminobenzylpenicillin, Penicillin, Aminobenzyl, 4-Thia-1-azabicyclo(3.2.0)heptane-2-carboxylic acid, 6-((aminophenylacetyl)amino)-3,3-dimethyl-7-oxo-, (2S-(2alpha,5alpha,6beta(S*)))-, (2S,5R,6R)-6-((R)-2-Amino-2-phenylacetamido)-3,3-dimethyl-7-oxo-4-thia-1-azabicyclo(3.2.0)heptane-2-carboxylic Acid, ampicillin (medication), ampicillin, Ampicillin [Chemical/Ingredient], aminobenzylpenicillin, ampicillins, Ampicillin, AMPICILLIN, Ampicillin (product), Ampicillin (substance)
Swedish Ampicillin
Czech ampicilin
Finnish Ampisilliini
German Aminobenzylpenizillin, Ampicillin, Penizillin, Aminobenzyl-
Russian PENITSILLIN, AMINOBENZIL, AMPITSILLIN, АМПИЦИЛЛИН, ПЕНИЦИЛЛИН, АМИНОБЕНЗИЛ
Japanese アミノベンジルペニシリン, アンピシリン, ペニシリン-アミノベンジル
Croatian AMPICILIN
Polish Penicylina aminobenzylowa, Ampicylina
Spanish Aminobencilpenicilina, aminobenzilpenicilina, ampicilina (producto), ampicilina (sustancia), ampicilina, Ampicilina, Aminobencil Penicilina
French Ampicilline
Italian Ampicillina
Portuguese Aminobenzilpenicilina, Ampicilina