Equine Rabies Immunoglobulin (ERIG) is a sterile, concentrated, and purified solution of immunoglobulins derived from the plasma of horses hyper-immunized with rabies virus vaccine. It provides immediate, passive immunity against the rabies virus following a Category III exposure (transdermal bites, licks on broken skin, contamination of mucous membrane with saliva) as per WHO and National Rabies Control Programme (NRCP) guidelines. It is a critical component of Post-Exposure Prophylaxis (PEP) and must be administered as soon as possible after exposure, infiltrated around and into the wound(s), with any remainder given intramuscularly at a site distant from the rabies vaccine administration.
Adult: 20 IU per kg body weight. For a 1500IU vial, calculate total required IU (20 x weight in kg). Infiltrate as much as possible into and around the wound(s). Any remaining volume should be administered by deep intramuscular injection, preferably in the anterolateral aspect of the thigh or deltoid muscle, AWAY from the site of rabies vaccine administration.
Note: 1. Perform skin sensitivity test if recommended by manufacturer/policy. 2. Calculate total dose (20 IU/kg). 3. Clean wounds thoroughly with soap and water, povidone-iodine. 4. Infiltrate the full dose of ERIG into and around all wounds using a fine needle. If wound volume is small, infiltrate as much as possible. 5. Administer any remaining immunoglobulin by IM injection at a site distant from the rabies vaccine site (e.g., opposite thigh/arm). 6. The first dose of rabies vaccine must be given concurrently but at a different anatomical site. NEVER administer ERIG and vaccine in the same syringe or same site.
ERIG contains high-titer, virus-neutralizing antibodies (immunoglobulins) against the rabies virus. Upon administration, these pre-formed antibodies bind directly to the rabies virus glycoprotein antigens, neutralizing the virus at the site of inoculation (wound) and in the circulation. This provides immediate, passive immunity, preventing the virus from entering peripheral nerves and central nervous system while the patient's own active immune response is being primed by the concurrently administered rabies vaccine.
Pregnancy: Pregnancy Category C. ERIG should be used if clearly needed for post-exposure prophylaxis. Rabies is nearly 100% fatal, and PEP is lifesaving. The benefits of preventing rabies far outweigh potential risks to the fetus.
Driving: Unlikely to affect driving ability. However, patients should be cautioned about the potential for delayed serum sickness reactions causing malaise or fever.
| Live Virus Vaccines (e.g., MMR, Varicella) | ERIG may interfere with the immune response to live virus vaccines. Administration of such vaccines should be deferred for at least 3 months after ERIG administration. | Moderate |
| Corticosteroids, Immunosuppressants | May theoretically blunt the active immune response to the concomitant rabies vaccine. Use with caution; avoid unless absolutely necessary. | Moderate |
| Other Immunoglobulins | May increase risk of systemic reactions. Not typically co-administered. | Low |
Same composition (Equine Rabies Immunoglobulin (1500IU)), different brands: