• Type: Amino-Penicillin
  • Dosage Forms: oral solution, capsule, tablet, chewable tablet, extended release tablet
  • Dosage Strengths: oral solution: 125, 200, 250, 400mg/5 mL; capsule: 250, 500mg; tablet: 500, 875mg; chewable tablet: 125, 250mg; extended release tablet: 775mg
  • Routes of Administration: PO
  • Common Trade Names: Amoxil; Moxatag, Trimox

Adult Dosing


  • 500-875mg PO q12

Strep Pharyngitis

  • 1000mg PO q24h x 10 days

Otitis Media

  • 1000mg PO q8h x 10 days


  • 1000mg PO q8h x 10 days

Dental Abscess

  • 1000mg PO x 1, then 500mg PO q8h x 3 days
  • If I&D

Chlamydial Cervicitis/Urethritis

  • 500mg PO q8h x 7 days
  • For pregnant patients

Lyme Disease

  • 500mg PO q8h x 14-21 days


Not 1st line treatment

  • Acute
    • Immunocompetent
      • 500mg PO q8h x 3-7 days
    • Immunocompromised
      • 1000mg PO q8h x 3-14 days
  • Chronic carrier
    • 1000mg PO q8h x 3 months

Typhoid Fever

Not 1st line treatment

  • 50-100mg/kg/day PO divided q6-8h x 14 days
  • First Dose: 12.5mg-33.3mg/kg PO x 1

Pediatric Dosing


  • <3mo: 20-30mg/kg/day PO divided q12h
    • First Dose: 10-15mg/kg PO x 1
    • Max: 30mg/kg/day
  • >3mo: 25-45mg/kg/day PO divided q12h
    • First Dose: 12.5-22.5mg/kg PO x 1
    • Max: 875mg/dose

Otitis Media

  • <2 months
    • 30mg/kg/day PO divided q12h x 10 days
    • First Dose: 15mg/kg PO x 1
  • 2 months - 5 years
    • 80-90mg/kg/day PO divided q12h x 10 days
    • First Dose: 40-45mg/kg PO x 1
    • Max: 1000mg/dose
  • 6-12 years
    • 80-90mg/kg/day PO divided q12h x 5-10 days
    • First Dose: 40-45mg/kg/day PO x 1
    • Max: 1000mg/dose

Community Acquired Pneumonia

  • 90mg/kg/day PO divided q12h x 5-10 days
  • First Dose: 45mg/kg PO x 1
    • Max
      • 3 months - 4 years: 500mg/dose
      • >5 years: 4000mg/day

Strep Pharyngitis

  • 50mg/kg Po q24h x 10 days
  • Max: 1000mg/day


  • 90mg/kg/day PO divided q8-12h x 10 days
  • Max: 1000mg/dose

H. pylori

  • 50mg/kg/day PO divided BID x 7-14 days
  • Max: 2000mg/day

Early Lyme Disease

  • 50mg/kg/day PO divided q8h x 14-21 days
  • First Dose: 16.6mg/kg PO x1
  • Max: 500mg/dose

Salmonella (>3mo)

  • 50-100mg/kg/day PO divided q8-12h
    • Acute: x 3-7 days
    • Acute Immunocompromised: 10-14 days
    • Chronic: 3 months

Typhoid Fever (>3mo)

Not 1st line treatment

  • 50-100mg/kg/day PO divided q6-8h x 14 days

Special Populations

  • Pregnancy Rating: B
  • Lactation: Use caution
  • Renal Dosing
    • Adult
    • Pediatric
  • Hepatic Dosing
    • Adult
    • Pediatric


  • Allergy to class/drug

Adverse Reactions


  • Anaphylaxis
  • Hypersensitivity vasculitis
  • Pseudomembranous colitis


  • Diarrhea, nausea/vomiting
  • Rash
  • Headache
  • AST/ALT elevation
  • Mucocutaneous candidiasis
  • Serum sickness-like reactions
  • Anemia, leukopenia, thrombocytopenia, eosinophilia
  • Hyperactivity, anxiety, insomnia, confusion behavioral changes
  • Tooth discoloration


  • Half-life: 3.7 hr (neonates), 1-2 hr (infants and children), 0.7 - 1.4 hr (adults)
  • Metabolism: Hepatic
  • Excretion: Urine
  • Mechanism of Action: Inhibits bacterial cell wall synthesis

Antibiotic Sensitivities[1]

Group Organism Sensitivity
Gram PositiveStrep. Group A, B, C, GS
Strep. PneumoniaeS
Viridans strepI
Strep. anginosus gpS
Enterococcus faecalisS
Enterococcus faeciumI
Staph. EpidermidisR
C. jeikeiumR
L. monocytogenesS
Gram NegativesN. gonorrhoeaeR
N. meningitidisS
Moraxella catarrhalisR
H. influenzaeI
E. coliI
Klebsiella spR
E. coli/Klebsiella ESBL+R
E coli/Klebsiella KPC+R
Enterobacter sp, AmpC negR
Enterobacter sp, AmpC posR
Serratia spR
Serratia marcescensX1
Salmonella spI
Shigella spI
Proteus mirabilisS
Proteus vulgarisR
Providencia sp.R
Morganella sp.R
Citrobacter freundiiR
Citrobacter diversusR
Citrobacter sp.R
Aeromonas spR
Acinetobacter sp.R
Pseudomonas aeruginosaR
Burkholderia cepaciaR
Stenotrophomonas maltophiliaR
Yersinia enterocoliticaR
Francisella tularensisX1
Brucella sp.X1
Legionella sp.R
Pasteurella multocidaS
Haemophilus ducreyiR
Vibrio vulnificusX1
MiscChlamydophila spR
Mycoplasm pneumoniaeR
Rickettsia spX1
Mycobacterium aviumX1
Bacteroides fragilisR
Prevotella melaninogenicaS
Clostridium difficileX1
Clostridium (not difficile)S
Fusobacterium necrophorumS
Peptostreptococcus sp.S


  • S susceptible/sensitive (usually)
  • I intermediate (variably susceptible/resistant)
  • R resistant (or not effective clinically)
  • S+ synergistic with cell wall antibiotics
  • U sensitive for UTI only (non systemic infection)
  • X1 no data
  • X2 active in vitro, but not used clinically
  • X3 active in vitro, but not clinically effective for Group A strep pharyngitis or infections due to E. faecalis
  • X4 active in vitro, but not clinically effective for strep pneumonia

See Also


  1. Sanford Guide to Antimicrobial Therapy 2014
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