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Antibiotic — Cephalosporin Pregnancy: Safe in pregnancy — no known teratogenicity; preferred for gonorrhoea treatment in pregnancy

Ceftriaxone

Brand names: Rocephin

Adult dose

Dose: 500 mg–2 g
Route: IM / IV
Frequency: Once daily (gonorrhoea: single 500 mg IM dose); every 12–24 hours for PID/sepsis
Max: 4 g/24h
First-line for gonorrhoea (500 mg IM stat — dual therapy with doxycycline per BASHH 2019). Used in PID (with doxycycline + metronidazole), obstetric sepsis, Group B Streptococcal (GBS) infections.

Paediatric dose

Dose: 50–100 mg/kg mg/kg
Route: IV / IM
Frequency: Once daily
Max: 4 g/day
BNFc: neonatal gonococcal ophthalmia — 25–50 mg/kg IV/IM single dose. Use calcium-free diluents in neonates — fatal ceftriaxone-calcium precipitate reported

Dose adjustments

Renal

No dose adjustment required in mild-moderate renal impairment; reduce dose if eGFR <10 mL/min/1.73m²

Hepatic

No dose adjustment required in mild-moderate hepatic impairment

Paediatric weight-based calculator

BNFc: neonatal gonococcal ophthalmia — 25–50 mg/kg IV/IM single dose. Use calcium-free diluents in neonates — fatal ceftriaxone-calcium precipitate reported

Clinical pearls

  • BASHH 2019: gonorrhoea dual therapy — ceftriaxone 500 mg IM + azithromycin 1 g PO (or doxycycline 100 mg BD × 7 days if azithromycin not tolerated)
  • Ceftriaxone 1 g dose for pharyngeal gonorrhoea — higher MIC at this site requires higher dose
  • RCOG GBS prophylaxis in labour: IV benzylpenicillin first-line; ceftriaxone for penicillin allergy without anaphylaxis risk
  • PID regimen: ceftriaxone 500 mg IM stat + doxycycline 100 mg BD + metronidazole 400 mg BD × 14 days
  • Fatal ceftriaxone-calcium precipitate in neonates — never administer IV ceftriaxone with calcium-containing fluids in neonates

Contraindications

  • Cephalosporin hypersensitivity
  • Penicillin allergy — 1–2% cross-reactivity (use with caution)
  • Premature neonates — avoid (calcium interaction risk)
  • Concurrent IV calcium-containing solutions in neonates

Side effects

  • Diarrhoea
  • C. difficile infection (low risk)
  • Transient LFT elevation
  • Biliary pseudolithiasis (prolonged use)
  • Rash
  • Anaphylaxis

Interactions

  • Calcium-containing IV solutions — avoid concurrent administration (precipitation risk)
  • Warfarin — enhanced anticoagulant effect

Monitoring

  • Renal function (prolonged use)
  • LFTs
  • Signs of C. difficile
  • INR (if on warfarin)

Reference: BNFc; BNF 90; BNFc; BASHH Gonorrhoea Guidelines (2019); BASHH PID Guidelines (2019); RCOG GBS Guidelines (2017). Verify against your local formulary and the latest BNF before prescribing.

Related

Curated clinical cross-links plus same-class fallbacks.

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