Amoxicillin
AMOXIL
What it isAminopenicillin that inhibits penicillin-binding proteins and cell-wall synthesis; common respiratory and ear infections.
Why this oneUnlike ampicillin, reliable oral absorption plus pneumococcal activity makes it a first-line outpatient respiratory antibiotic.
What limits itBeta-lactamase producers escape it — that is what clavulanate is for. An EBV-associated rash does not by itself prove penicillin allergy.
FDA-approved for
- bacterial infections (~1974)
FDA label
Read the full label on DailyMed ↗
| FDA dosing | Population | Start | Target | Max |
|---|---|---|---|---|
| General infections | Adult | 750-1750 mg/day divided q8-12h | ||
| General infections | Pediatric >3 months | 20-45 mg/kg/day divided q8-12h | ||
| General infections | Neonates/infants <=3 months | up to 30 mg/kg/day divided q12h | 30 mg/kg/day | |
| H. pylori (triple therapy, with clarithromycin + lansoprazole) | Adult | 1 g BID x14 days | ||
| H. pylori (dual therapy, with lansoprazole) | Adult | 1 g TID x14 days |
Renal GFR 10-30 mL/min: 500 or 250 mg q12h; GFR <10 mL/min: 500 or 250 mg q24h; hemodialysis: 500 or 250 mg q24h plus a dose during and after dialysis; do not use 875 mg dose if GFR <30 mL/min.
Hepatic Undefined
Instructions
- Take at the start of a meal to minimize GI intolerance
- Continue at least 48-72 h after patient is asymptomatic; treat S. pyogenes infections at least 10 days
Contraindications
- Serious hypersensitivity (e.g., anaphylaxis, Stevens-Johnson syndrome) to beta-lactams (penicillins, cephalosporins)
Cautions
- Serious/fatal anaphylactic reactions
- Severe cutaneous adverse reactions (SCAR)
- Drug-induced enterocolitis syndrome (DIES)
- Clostridioides difficile-associated diarrhea (CDAD)
Adverse reactions
- Nausea
- Vomiting
- Diarrhea
- Rash
Pregnancy Pregnancy Category B; animal studies showed no evidence of fetal harm; no adequate and well-controlled studies in pregnant women.
Lactation Undefined
NO BOXED WARNINGS
Principal riskHypersensitivity, including anaphylaxis
Cost, est. cash$4–$80/month
Generic entry1982
Classes and tags
Clinical profile
Legacy pregnancy categoryB
Defining liabilityAllergy, gastrointestinal effects and agent-specific renal, hepatic, hematologic or interaction risks.
Mechanism of action: Amoxicillin ballicule
Open Amoxicillin in the interactive console ↗
Memory aids: mascots and interaction avatars
Β lactam ring → the defining structure of penicillins and cephalosporins
