Equirab (Rabies Immunoglobulin) Dosing for a 20kg Child
For a 20kg child requiring rabies post-exposure prophylaxis, administer 400 IU of Equirab (equine rabies immunoglobulin), calculated as 20 IU/kg body weight, with as much as anatomically feasible infiltrated around and into the wound(s), and any remaining volume injected intramuscularly at a site distant from the vaccine administration. 1
Dosing Calculation
- The standard dose of rabies immunoglobulin (RIG) is 20 IU/kg body weight, applicable to all age groups including children 1
- For a 20kg child: 20 kg × 20 IU/kg = 400 IU total dose 1
- If using Equirab at a concentration of 300 IU/mL (standard equine RIG concentration), this equals approximately 1.3 mL total volume 2
Administration Technique
- Infiltrate the full dose around and into the wound(s) if anatomically feasible as the primary route of administration 1
- Any remaining volume that cannot be infiltrated into wounds should be administered intramuscularly at a site distant from vaccine administration (never in the same anatomical site as the rabies vaccine) 1
- For wound infiltration in children, research suggests approximately 0.75 mL per cm of wound length or 3.18 mL per cm² of wound area can be used as a practical guide 2
- Never administer RIG in the same syringe as the rabies vaccine 1
Critical Timing Considerations
- RIG should be administered on day 0 when post-exposure prophylaxis is initiated, in conjunction with the first dose of rabies vaccine 1
- If RIG was not given on day 0, it can still be administered up to and including day 7 after the first vaccine dose 1
- Beyond day 7, RIG is not indicated because antibody response to the vaccine is presumed to have occurred 1
Vaccine Coadministration
- The child must also receive rabies vaccine: four 1-mL doses on days 0,3,7, and 14 (updated 4-dose schedule for previously unvaccinated persons) 1
- For young children, vaccine should be administered intramuscularly in the anterolateral aspect of the thigh (deltoid is acceptable for older children) 1
- Never use the gluteal area for vaccine administration as this results in lower antibody titers 1
Important Caveats
- Do not exceed the recommended 20 IU/kg dose of RIG, as higher doses can partially suppress active antibody production from the vaccine 1
- Equine RIG (eRIG) like Equirab has been used effectively in developing countries with low incidence of adverse reactions (0.8%-6.0%), though human RIG is preferred when available 1
- Wound cleansing with soap and water (and virucidal agent like povidone-iodine if available) should precede RIG administration 1
- For severe or multiple wounds in small children, dilution of RIG in normal saline may be necessary to provide adequate volume for complete wound infiltration 3