Beta-lactam antibiotic Pregnancy: Safe in pregnancy.

Amoxicillin (Otitis Media / Sinusitis)

Brand names: Amoxil

Adult dose

Dose: 500 mg three times daily for 5–7 days

Route: Oral

Frequency: Three times daily

Max: 3 g/day

Acute otitis media (adults): 500 mg TDS for 5–7 days. Acute sinusitis (if antibiotics needed): 500 mg TDS for 5 days. Most acute OM in adults is viral — antibiotics only if: bilateral, severe symptoms, or systemically unwell. Consider NSAID/analgesia first.

Paediatric dose

Dose: 40 mg/kg

Route: Oral

Frequency: Three times daily

Max: 500 mg/dose

Concentration: 125 mg/ml

AOM: 40–90 mg/kg/day in 3 divided doses (NICE NG98: high-dose if treatment failure). <2 years bilateral AOM or with discharge: 90 mg/kg/day (max 3 g/day). Standard doses: <2 years 62.5 mg TDS; 2–5 years 125 mg TDS; 5–18 years 250 mg TDS.

Dose adjustments

Renal

Reduce dose or increase interval if eGFR <30.

Hepatic

No dose adjustment required.

Paediatric weight-based calculator

Patient weight (kg)

Clinical pearls

NICE: 'watchful waiting' approach for AOM in children >2 years with non-severe symptoms — antibiotics only if not improving after 2–3 days
Under 2 years with bilateral AOM, discharge, or systemically unwell: treat immediately
Co-amoxiclav for treatment failure (likely H. influenzae or M. catarrhalis)
Otitis externa (swimmer's ear): topical treatment preferred (acetic acid drops or antibiotic/steroid drops)

Contraindications

Penicillin hypersensitivity
Infectious mononucleosis

Side effects

Diarrhoea
Rash (maculopapular)
GI upset
Oral/vaginal candidiasis
Anaphylaxis (rare)

Interactions

Warfarin — may increase INR
Methotrexate — reduced excretion

Monitoring

Response to treatment
Hearing if recurrent AOM

Reference: BNFc; BNF; NICE NG98 AOM; PHE AOM Guidelines. Verify against your local formulary and the latest BNF before prescribing.

Curated clinical cross-links plus same-class fallbacks.

Calculators

Pathways