• 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 Positive Strep. Group A, B, C, G S
Strep. Pneumoniae S
Viridans strep I
Strep. anginosus gp S
Enterococcus faecalis S
Enterococcus faecium I
Staph. Epidermidis R
C. jeikeium R
L. monocytogenes S
Gram Negatives N. gonorrhoeae R
N. meningitidis S
Moraxella catarrhalis R
H. influenzae I
E. coli I
Klebsiella sp R
E. coli/Klebsiella ESBL+ R
E coli/Klebsiella KPC+ R
Enterobacter sp, AmpC neg R
Enterobacter sp, AmpC pos R
Serratia sp R
Serratia marcescens X1
Salmonella sp I
Shigella sp I
Proteus mirabilis S
Proteus vulgaris R
Providencia sp. R
Morganella sp. R
Citrobacter freundii R
Citrobacter diversus R
Citrobacter sp. R
Aeromonas sp R
Acinetobacter sp. R
Pseudomonas aeruginosa R
Burkholderia cepacia R
Stenotrophomonas maltophilia R
Yersinia enterocolitica R
Francisella tularensis X1
Brucella sp. X1
Legionella sp. R
Pasteurella multocida S
Haemophilus ducreyi R
Vibrio vulnificus X1
Misc Chlamydophila sp R
Mycoplasm pneumoniae R
Rickettsia sp X1
Mycobacterium avium X1
Anaerobes Actinomyces S
Bacteroides fragilis R
Prevotella melaninogenica S
Clostridium difficile X1
Clostridium (not difficile) S
Fusobacterium necrophorum S
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