Equine Rabies Immunoglobulin (ERIG) is a sterile, concentrated, and purified solution of immunoglobulins derived from the plasma of horses hyperimmunized with rabies virus vaccine. It provides immediate, passive immunity against the rabies virus by neutralizing the virus at the site of exposure before it can enter the nervous system. It is a critical component of Category III rabies post-exposure prophylaxis (PEP) as per WHO and National Centre for Disease Control (NCDC), India guidelines, and is used in conjunction with rabies vaccine.
Adult: 40 International Units (IU) per kilogram body weight.
Note: 1. Calculate total dose: Weight (kg) x 40 IU. 2. Clean all wounds thoroughly with soap and water, povidone-iodine, or ethanol for at least 15 minutes. 3. Infiltrate as much of the calculated ERIG dose as possible into and around the depth and margins of all wounds using a fine needle. 4. If wound volume is insufficient for full dose, administer any remaining volume by DEEP INTRAMUSCULAR injection at an anatomical site distant from the rabies vaccine injection site (e.g., contralateral anterolateral thigh or deltoid). 5. NEVER administer in the same syringe or at the same site as the rabies vaccine. 6. For multiple wounds, dilute the total dose with normal saline to a sufficient volume for adequate infiltration of all sites.
ERIG contains high-titer neutralizing antibodies (IgG) against the rabies virus. Upon infiltration into and around the wound site, these antibodies bind to the rabies virus glycoprotein, preventing viral attachment and entry into peripheral nerve endings. This provides immediate, passive neutralization of the virus at the local site of inoculation, complementing the active immunity later induced by the rabies cell culture vaccine.
Pregnancy: Pregnancy Category C: Animal reproduction studies have not been conducted. Should be used during pregnancy only if clearly needed, as rabies exposure is a life-threatening condition. The benefits of preventing rabies far outweigh potential risks.
Driving: May cause dizziness or malaise. Patients should be cautioned about driving or operating machinery if they experience such effects.
| Live Virus Vaccines (e.g., MMR, Varicella, Yellow Fever) | 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 (e.g., Azathioprine, Cyclosporine) | May theoretically reduce the efficacy of active immunization with the concomitant rabies vaccine. Use with caution and monitor RVNA titers if possible. | Moderate |
| Other Immunoglobulin Preparations | May increase the risk of systemic adverse reactions. | Low |