Open Vial Policy for Rabies Immunoglobulin
Rabies Immunoglobulin (HRIG) does not follow an open vial policy and must be used as a single-dose product. HRIG is supplied in pre-measured vials (2-mL containing 300 IU for pediatric use and 10-mL containing 1,500 IU for adult use) that are intended for single-patient administration only 1.
Key Product Characteristics
HRIG is formulated as a concentrated gamma globulin solution that lacks preservatives, making multi-dose use unsafe and impractical. The product is standardized to contain 150 IU/mL and is prepared through cold ethanol fractionation from plasma of hyperimmunized human donors 1.
Dosing Requirements That Preclude Open Vial Use
The entire calculated dose of HRIG (20 IU/kg body weight) must be administered on day 0 of post-exposure prophylaxis, with as much as anatomically feasible infiltrated directly into and around the wound(s). 1, 2, 3. Any remaining volume after wound infiltration is administered intramuscularly at a site distant from vaccine administration 1.
- Exceeding the recommended 20 IU/kg dose is contraindicated because it may partially suppress active antibody production from the vaccine series 1, 3.
- The individualized weight-based dosing and requirement for immediate wound infiltration means each vial must be dedicated to a single patient 1, 2.
Critical Timing Constraints
HRIG must be administered on day 0 when PEP is initiated, or can be given up to and including day 7 of the vaccine series if not initially administered 1, 4. After day 7, HRIG should not be given as it may interfere with the active immune response to vaccination 1, 4.
This narrow therapeutic window, combined with the need for immediate wound infiltration, makes storing and reusing opened vials clinically inappropriate and potentially dangerous 2, 3.
Storage and Stability Considerations
Once a vial is opened and the sterile seal is broken, the lack of preservatives in HRIG formulations means the product cannot be safely stored for future use. The product must be used immediately after opening to maintain sterility and potency 1.