C. diff Risk


Oral Bioavailability


Approximate Cost



500 mg PO q8h (Urinary tract infection) 1000 mg PO q8h (Community acquired pneumonia in pregnancy)

Usual dose: 45-60 mg/kg/24h PO divided q8h
High dose: 75-90 mg/kg/24h PO divided q8h. High dose can be divided q12h for otitis media.
Maximum: 4 g/24h
Usual maximum adult dose 1 g po q8h
Pharyngitis (Group A streptococcal infection): Amoxicillin 50 mg/kg/24h PO divided q12-24h
Maximum: 1 gram/24h

20-30 mg/kg/24h PO divided q12h

General Information

Common Usage

Therapy of streptococcal, enterococcal infections as well as susceptible gram negative infections. Commonly used for upper respiratory infections and urinary tract infection (when organisms susceptible)

Adverse Effects

  • Allergy/rash (immediate or delayed)

  • Cytopenias

  • EBV related rash (not allergy)

Oral Liquids

Concentration: 50 mg/mL
Taste: very palatable
Not all strengths of oral liquids are listed nor are available on IWK formulary

Tablet/Capsule Strengths

250 mg capsule
500 mg capsule
Tablets and capsules are preferred especially over an unpleasant tasting liquid.
Not all strengths of oral tablets/capsules are listed and they are not all available on the IWK formulary.


Antimicrobial class: Aminopenicillin

Average serum half life: Neonates, full-term: 3.7 hours
Infants and children: 1 to 2 hours

Route of Elimination: Renal excretion (60% unchanged drug)