Rabies Immunoglobulin Dosing for Dog Bite
The recommended dose of rabies immunoglobulin (RIG) for a dog bite is 20 IU/kg body weight, administered once at the beginning of post-exposure prophylaxis. 1, 2
Dosing Specifications
- The 20 IU/kg formula is universally applicable to all age groups, including children and adults. 1, 2
- This standardized weight-based dosing applies to both human rabies immunoglobulin (HRIG) and equine rabies immunoglobulin (ERIG). 2
- Do not exceed the recommended dose, as higher amounts can partially suppress the active antibody response to the vaccine. 1, 2
Administration Technique
The full calculated dose should be thoroughly infiltrated in and around the wound(s) if anatomically feasible. 1, 2 This local infiltration is critical—the recommendation was strengthened based on reports of rare post-exposure prophylaxis failures when inadequate amounts were infiltrated at exposure sites. 1, 2
- Any remaining volume after wound infiltration should be administered intramuscularly at a site distant from the vaccine injection. 1, 2
- Never administer RIG in the same syringe or at the same anatomical site as the rabies vaccine. 1, 2
Timing Considerations
- RIG is administered only once, ideally at the initiation of post-exposure prophylaxis. 1, 2
- If RIG was not given initially, it can still be administered through day 7 after the first vaccine dose. 1, 2
- Beyond day 7, RIG is not indicated because an antibody response to the cell culture vaccine is presumed to have occurred. 1, 2
Vaccine Combination
Post-exposure prophylaxis requires both RIG and rabies vaccine for previously unvaccinated persons. 1, 2 The current recommendation is a 4-dose vaccine schedule (days 0,3,7, and 14) along with RIG for immunocompetent patients. 2 Immunocompromised patients should receive a 5-dose schedule. 2
Exception
Persons who have previously received complete rabies vaccination (pre-exposure or post-exposure) require only vaccine without RIG. 1, 2
Common Pitfalls to Avoid
- Gluteal administration of vaccine should never be used, as this results in lower neutralizing antibody titers. 1
- Do not delay RIG administration waiting for animal observation results—begin immediately for category III exposures (bites or scratches with broken skin). 2
- Prophylaxis can be discontinued if laboratory testing confirms the animal was not rabid. 2
Essential Wound Care
Immediate and thorough washing of all bite wounds with soap and water, plus a virucidal agent such as povidone-iodine, is critical for rabies prevention. 1, 2 Animal studies demonstrate that wound cleansing alone markedly reduces rabies likelihood. 1