Antitetanus Antiserum Administration Route
Tetanus immune globulin (TIG) should be administered intramuscularly, NOT intravenously, for both prophylaxis and treatment of tetanus. The FDA-approved formulation (HyperTET) is specifically indicated for deep intramuscular injection 1.
Route of Administration
The evidence is unequivocal that antitetanus antiserum is given via intramuscular (IM) injection:
- Standard prophylactic dose: 250 units administered by deep intramuscular injection for adults and children ≥7 years 1
- Pediatric dosing: May be calculated at 4.0 units/kg, though the full 250-unit dose is often advisable regardless of child size 1
- Treatment of active tetanus: Dosing adjusted according to severity, but route remains intramuscular 1
Critical Administration Details
When administering TIG with tetanus toxoid concurrently:
- Use separate syringes
- Inject at separate anatomical sites (different extremities) 2, 1
- This prevents potential interference between active and passive immunization
Important Caveats
When IV Immune Globulin May Be Substituted
The CDC guidelines note that intravenous immune globulin (IVIG) may be substituted for TIG only when TIG is unavailable 2. This is a supply-shortage contingency, not a preferred route. Standard TIG products are formulated for IM use only.
No Direct IV Push or Infusion
The FDA labeling for HyperTET makes no mention of intravenous administration, diluted or undiluted 1. The product is designed and approved exclusively for intramuscular injection.
Clinical Context
In mass-casualty settings where TIG supplies may be limited, priority should be given to patients least likely to have adequate primary vaccination (persons >60 years, immigrants from regions with lower vaccination rates) 2. The 250-unit IM dose remains standard even when supplies are constrained—rationing occurs by patient selection, not dose reduction.
The question of dilution is moot because antitetanus antiserum is not administered intravenously in standard practice.