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Aminopenicillin Antibiotic Pregnancy: Compatible — widely used in pregnancy

Amoxicillin (Paediatric)

Brand names: Amoxil

Adult dose

Dose: 250–500 mg TDS or 500 mg–1 g TDS (severe infections)
Route: Oral or IV
Frequency: TDS
Max: 3 g/day oral; 12 g/day IV (severe infections)
See adult infectious disease entry for full adult dosing

Paediatric dose

Dose: 25 mg/kg
Route: Oral or IV
Frequency: TDS
Max: 500 mg per dose (oral); 1 g per dose (IV)
Concentration: 125 mg/5 mL or 250 mg/5 mL suspension mg/ml
BNF for Children / NICE NG143: standard 40 mg/kg/day in 3 divided doses (≈13 mg/kg TDS); high-dose CAP: 40–90 mg/kg/day (≈30 mg/kg TDS). Calculator uses 25 mg/kg (representative single dose — upper oral range). Neonates: IV 30 mg/kg every 12h (first week), every 8h (1–4 weeks). Source: BNF for Children 2024; NICE NG143

Dose adjustments

Renal

Reduce dose frequency in renal impairment

Hepatic

No dose adjustment required

Paediatric weight-based calculator

BNF for Children / NICE NG143: standard 40 mg/kg/day in 3 divided doses (≈13 mg/kg TDS); high-dose CAP: 40–90 mg/kg/day (≈30 mg/kg TDS). Calculator uses 25 mg/kg (representative single dose — upper oral range). Neonates: IV 30 mg/kg every 12h (first week), every 8h (1–4 weeks). Source: BNF for Children 2024; NICE NG143

Clinical pearls

  • NICE NG143: amoxicillin 40–90 mg/kg/day (3 divided doses) for typical community-acquired pneumonia — higher doses than previously recommended
  • Always ask about penicillin allergy before prescribing
  • Avoid in confirmed EBV mononucleosis — widespread maculopapular rash occurs in 80% of patients (not true allergy)
  • Suspension should be shaken before use and refrigerated after reconstitution

Contraindications

  • Penicillin allergy
  • Infectious mononucleosis (risk of extensive rash)

Side effects

  • Diarrhoea (common in children)
  • Rash (especially with mononucleosis — 80%)
  • Nausea
  • Urticaria
  • Anaphylaxis (rare)

Interactions

  • Methotrexate — reduced renal clearance of MTX
  • Warfarin — may slightly increase INR
  • Live oral typhoid vaccine — antibiotic reduces efficacy

Monitoring

  • Clinical response (temperature, symptom resolution)
  • Renal function in severe infection
  • Allergic reactions (particularly in first dose)

Reference: BNF for Children; NICE NG143 Pneumonia; Red Book AAP. Verify against your local formulary and the latest BNF before prescribing.

Related

Curated clinical cross-links plus same-class fallbacks.

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