The drug atlas
Child Health/Paediatric antimicrobials

Antimicrobials in children

also: benzylpenicillin strep · amoxicillin paeds · cefotaxime neonate · paediatric antibiotics

Overview

The antibiotics/antivirals for common childhood infections, in context — same agents as adults but with the crucial paediatric/neonatal age rules (full class mechanisms live in the Antimicrobials section).

Mechanism

Pathogen-directed antimicrobials. The paediatric distinctives are: weight-based dosing, the neonatal cautions (ceftriaxone displaces bilirubin → use cefotaxime), the need for Listeria cover under 3 months, and the age contraindications (tetracyclines, chloramphenicol grey-baby).

Indications

  • Common paediatric infections (ENT, chest, meningitis, neonatal sepsis, UTI, viral)

The agents

Phenoxymethylpenicillin / benzylpenicillinpenicillin

PO / IM

Strep throat & scarlet fever (penicillin V 10 days); IM benzylpenicillin pre-hospital for suspected meningococcal sepsis.

Amoxicillinaminopenicillin

PO/IV

First-line acute otitis media (if antibiotic indicated) and community pneumonia; add to meningitis regimen <3mo for Listeria.

Cefotaxime vs ceftriaxone3rd-gen cephalosporin

IV

Bacterial meningitis: cefotaxime if <3 months (ceftriaxone displaces bilirubin → kernicterus + Ca-incompatibility); ceftriaxone if ≥3 months.

Gentamicinaminoglycoside

IV

Neonatal sepsis = IV benzylpenicillin + gentamicin (NICE).

Macrolide (clarithromycin/azithromycin)macrolide

PO

Penicillin allergy, atypical pneumonia, and whooping cough (pertussis).

Aciclovirantiviral

IV/PO

Neonatal HSV, HSV encephalitis, and severe/immunocompromised chickenpox; VZIG for post-exposure prophylaxis.

Nitrofurantoin / trimethoprimUTI agents

PO

Childhood UTI (avoid nitrofurantoin <3 months / at term).

Adverse effects

Amoxicillin rash with EBV (glandular fever)classic

Not a true penicillin allergy — common paeds pitfall.

Ceftriaxone → bilirubin displacement (kernicterus) in neonatesserious

Use cefotaxime under 3 months.

Gentamicin: oto/nephrotoxicity (monitor levels)serious
C. difficile / GI upset (broad-spectrum)common

Cautions & contraindications

Ceftriaxone in neonates (esp. jaundiced / on calcium-containing fluids)paediatric

Kernicterus; use cefotaxime.

Tetracyclines <12 yearspaediatric

Teeth/bone.

Chloramphenicol in neonatespaediatric

Grey baby syndrome.

Missing Listeria cover in meningitis <3 monthspaediatric

Cephalosporins don't cover Listeria — add amoxicillin/ampicillin.

Interactions

  • As per individual agents (see Antimicrobials section)

Monitoring & kinetics

Weight-based dosing; gentamicin levels; response

Weight-based; route per severity. See the Antimicrobials section for full class pharmacology.

Source: NICE NG143/NG240 — Fever / sepsis in under 5s · BNF for Children — Antibacterials