Equine antitoxin (passive immunisation)
Diphtheria antitoxin
Brand names: Specialist UKHSA supply
Adult dose
Dose: 10,000–100,000 units IV/IM (per severity and surface involvement); per UKHSA
Route: IV / IM
Frequency: Single dose
Clinical pearls
- UKHSA Green Book ch 15 / ImmForm: clinical diphtheria suspicion → UKHSA Imported Fever Service for antitoxin release
- Skin test before administration recommended (anaphylaxis risk)
- Prompt treatment essential — antitoxin neutralises only unbound toxin
- Notifiable disease
Contraindications
- Equine serum hypersensitivity (relative; weigh risk-benefit)
Side effects
- Anaphylaxis (significant)
- Serum sickness (1–2 weeks post-dose)
- Fever
- Hypersensitivity reactions
Monitoring
- Anaphylaxis observation
- Serum sickness signs
- Cardiac/neurological complications of diphtheria
Reference: BNF; UKHSA Green Book ch 15; UKHSA Imported Fever Service; https://bnf.nice.org.uk/drugs/diphtheria-antitoxin/. Verify against your local formulary and the latest BNF before prescribing.
Related
Curated clinical cross-links plus same-class fallbacks.
Pathways
- Infective Endocarditis · ESC 2023 Infective Endocarditis Guidelines; NICE NG41
- Eczema Herpeticum · BAD; NICE CKS
- Suspected Bacterial Meningitis (Adult) · NICE NG240 (2024); NICE NG143 (paeds)
- Clostridioides difficile Colitis · NICE NG199 (2021); IDSA/SHEA 2021
- Returning Traveller — Fever · NaTHNaC; PHE; ESCMID 2018
- Malaria — Diagnosis & Management · PHE 2016; WHO 2023