Tetanus Immunoglobulin Dosing for Established Tetanus
For established cases of tetanus, administer 3,000-6,000 units of human tetanus immunoglobulin (TIG) intramuscularly, which is substantially higher than the 250-unit prophylactic dose used in wound management. 1
Therapeutic Dosing for Active Disease
The CDC recommends 3,000-6,000 units as the standard therapeutic dose for active tetanus cases, representing a 12-24 fold increase over prophylactic dosing. 1
This higher dose is necessary because TIG neutralizes circulating tetanus toxin but cannot reverse toxin already bound to nerve endings, making early and adequate dosing critical. 1
The immunoglobulin should be administered as soon as possible after diagnosis to maximize clinical benefit. 1
Administration Technique
TIG must be given at a different anatomic site than any tetanus toxoid-containing vaccine, using separate syringes. 2
The intramuscular route is the standard recommended approach for the therapeutic dose. 1
Intrathecal Administration Considerations
While intrathecal administration has been studied as an alternative route, the evidence presents important nuances:
Meta-analysis data suggest intrathecal therapy may reduce mortality (RR 0.71,95% CI 0.62-0.81) compared to intramuscular administration alone. 3
Intrathecal doses studied range from 250-1,500 IU, substantially lower than intramuscular therapeutic doses. 4, 5
However, intrathecal doses above 1,000 IU have been associated with reversible paraplegia, raising significant safety concerns. 6
A recent pilot study demonstrated feasibility and safety of intrathecal administration in resource-appropriate settings, though this was a small study of only 5 patients. 7
Critical Clinical Caveats
Despite optimal treatment with TIG, tetanus still carries significant mortality risk, underscoring that immunoglobulin is only one component of comprehensive tetanus management. 1
The distinction between prophylactic dosing (250 units for wound management) and therapeutic dosing (3,000-6,000 units for established disease) is critical—using prophylactic doses for active tetanus would be inadequate. 2, 1
Intrathecal administration, while potentially beneficial based on research evidence, is not part of standard CDC guideline recommendations and should only be considered in specialized settings with appropriate expertise and monitoring capabilities. 3, 7, 6