Tetanus Immunoglobulin Dosing
Prophylactic Dose for Wound Management
The recommended prophylactic dose of tetanus immunoglobulin (TIG) is 250 units intramuscularly for both adult and pediatric patients, administered when a patient has received fewer than 3 lifetime doses of tetanus toxoid or has unknown/uncertain vaccination history. 1, 2
When TIG is Required
TIG is indicated in the following scenarios:
- Patients with <3 documented tetanus toxoid doses presenting with any wound (clean or contaminated) 1, 3, 2
- Patients with unknown or uncertain vaccination history presenting with any wound 1, 2
- Severely immunocompromised patients (HIV infection, severe immunodeficiency) with contaminated wounds, regardless of their tetanus immunization history 1, 3
When TIG is NOT Required
Patients with ≥3 documented tetanus toxoid doses do NOT need TIG, regardless of wound type or time since last vaccination. 1, 3, 2 These patients only require tetanus toxoid-containing vaccine (Tdap preferred) based on time intervals:
- Clean, minor wounds: Give tetanus toxoid only if ≥10 years since last dose 1, 3, 2
- Contaminated/tetanus-prone wounds: Give tetanus toxoid only if ≥5 years since last dose 1, 3, 2
Critical Administration Details
- Always administer TIG and tetanus toxoid vaccine at separate anatomic sites using separate syringes to prevent interference with the immune response 1, 4, 2
- The 250-unit dose is universal for both adults and children—there is no weight-based dosing for prophylaxis 1, 3
- Human TIG is strongly preferred over equine antitoxin because it provides longer protection and causes fewer adverse reactions 1
Special Population Considerations
In mass-casualty settings with limited TIG supply, prioritize administration to patients >60 years of age and immigrants from regions outside North America/Europe, as these populations are least likely to have adequate protective antibody levels 1, 3
Therapeutic Dose for Active Tetanus
For established tetanus cases, the therapeutic dose is 3,000-6,000 units of TIG, which is 12-24 times higher than the prophylactic dose. 5 This higher dose is necessary to neutralize circulating tetanus toxin, though it cannot neutralize toxin already bound to nerve endings 5.
Treatment Protocol for Active Tetanus
- Administer TIG 3,000-6,000 units as soon as possible after diagnosis 5
- Give tetanus toxoid vaccine simultaneously at a separate site to initiate active immunity, as natural tetanus infection provides no immunity 4, 5
- Perform thorough surgical debridement of all necrotic tissue to remove anaerobic conditions 4
The evidence from a case report showed successful treatment with 6,000 IU of human TIG in a previously immunized patient who developed mild tetanus after cat scratches 6, supporting the higher therapeutic dosing range.
Common Pitfall to Avoid
Do not confuse prophylactic dosing (250 units) with therapeutic dosing (3,000-6,000 units). The prophylactic dose is inadequate for treating active tetanus cases 5. Despite optimal treatment, tetanus still carries an 18-21% case fatality rate, emphasizing the critical importance of prevention through proper immunization 4.