Usage
- Rabies human monoclonal antibody (RMAb) is prescribed for post-exposure prophylaxis (PEP) of rabies in individuals suspected of exposure to the rabies virus. This includes bite wounds, scratches, and other forms of contact with potentially infected animals. It is always used in conjunction with the rabies vaccine.
- Pharmacological Classification: Passive Immunizing Agent, Biologic
- Mechanism of Action: RMAb provides immediate passive immunity by neutralizing the rabies virus before it can establish infection in the nervous system. It binds to the rabies virus glycoprotein, preventing the virus from entering host cells.
Alternate Names
- Rabies Immunoglobulin (but distinct from human or equine derived rabies immunoglobulin)
- Brand Names: Rabishield
How It Works
- Pharmacodynamics: RMAb binds to the rabies virus glycoprotein, effectively neutralizing the virus. It prevents viral entry into cells, thereby blocking the spread of the virus to the central nervous system.
- Pharmacokinetics: Administered intramuscularly (IM), and locally infiltrated around the wound. The antibodies are distributed throughout the body and reach peak serum concentrations relatively quickly. Metabolism and elimination data specific to RMAbs are limited, but antibodies are generally catabolized into amino acids.
- Mode of Action: The monoclonal antibodies bind to specific epitopes on the rabies virus glycoprotein, preventing its interaction with host cell receptors. This neutralization inhibits viral entry into cells and subsequent replication.
- Receptor Binding/Enzyme Inhibition/Neurotransmitter Modulation: Directly targets the rabies virus via receptor binding (to the viral glycoprotein). No known enzyme inhibition or neurotransmitter modulation is directly associated with its mechanism of action.
- Elimination Pathways: The exact elimination pathways of RMAbs aren’t fully characterized, but it’s expected to follow typical antibody degradation pathways.
Dosage
Standard Dosage
Adults:
- 3.33 IU/kg body weight administered once at the beginning of PEP, ideally as soon as possible after exposure. As much as anatomically feasible should be infiltrated into and around the wound. Any remaining volume should be injected intramuscularly at a site distant from the vaccine administration.
Children:
- Same as adult dosing: 3.33 IU/kg body weight. Administer in the same manner as for adults (wound infiltration followed by IM injection if necessary).
- Pediatric Safety Considerations: No specific pediatric safety concerns distinct from those for adults.
Special Cases:
- Elderly Patients: No specific dosage adjustments are typically necessary.
- Patients with Renal Impairment: No specific dosage adjustments are typically necessary.
- Patients with Hepatic Dysfunction: No specific dosage adjustments are typically necessary.
- Patients with Comorbid Conditions: No specific dosage adjustments based solely on comorbidities are generally required. Dosage adjustments may be considered in certain clinical situations on case-by-case basis.
Clinical Use Cases
The use of RMAb is specifically for rabies post-exposure prophylaxis (PEP) following suspected exposure to the rabies virus, and its use is not indicated in the clinical scenarios you listed (intubation, surgical procedures, etc.).
Dosage Adjustments
- Dose modifications are primarily based on body weight (3.33 IU/kg), not specific organ dysfunctions or other conditions.
Side Effects
Common Side Effects
- Pain, redness, swelling, or itching at the injection site
- Mild fever
- Headache
- Muscle aches
- Nausea
Rare but Serious Side Effects
- Allergic reactions (anaphylaxis)
Long-Term Effects
- No known long-term adverse effects associated specifically with RMAb.
Adverse Drug Reactions (ADR)
- Allergic reactions should be managed appropriately.
Contraindications
- Known hypersensitivity to the product or any of its components.
Drug Interactions
- RMAb may theoretically interfere with the immune response to live attenuated vaccines. Live vaccines should generally be given either 14 days before or 2 weeks after the RMAb administration or at a distant site from RMAb injection.
Pregnancy and Breastfeeding
- Data are limited. Administer only if the potential benefits outweigh the risks.
Drug Profile Summary
- Mechanism of Action: Neutralizes rabies virus by binding to its glycoprotein, preventing viral entry into cells.
- Side Effects: Injection site reactions, fever, headache, muscle aches, nausea. Rarely, allergic reactions.
- Contraindications: Hypersensitivity to the product.
- Drug Interactions: Potential interference with live attenuated vaccines.
- Pregnancy & Breastfeeding: Limited data; administer only if benefits outweigh risks.
- Dosage: 3.33 IU/kg, once, with wound infiltration and IM injection of the remaining dose.
- Monitoring Parameters: Observe for allergic reactions.
Popular Combinations
- Rabies Vaccine: Always used in conjunction with rabies vaccine for post-exposure prophylaxis.
Precautions
- General Precautions: Screen for hypersensitivity reactions. Ensure proper wound cleansing.
- Specific Populations:
- Pregnant Women: Use only if clearly indicated.
- Breastfeeding Mothers: Use with caution.
- Children & Elderly: Standard dosage based on weight.
FAQs (Frequently Asked Questions)
Q1: What is the recommended dosage for Rabies Human Monoclonal Antibody?
A: 3.33 IU/kg body weight, administered once at the start of PEP.
Q2: How is Rabies Human Monoclonal Antibody administered?
A: It’s infiltrated around the wound and any remaining volume is administered intramuscularly at a site distant from vaccine administration.
Q3: Should Rabies Human Monoclonal Antibody be used alone for rabies PEP?
A: No, it should always be used in conjunction with the rabies vaccine.
Q4: What is the difference between Rabies Human Monoclonal Antibody and Rabies Immunoglobulin (RIG)?
A: RMAb is composed of monoclonal antibodies, while RIG is derived from pooled human or equine serum. RMAb typically has a lower required dose than RIG.
Q5: Are there any contraindications to Rabies Human Monoclonal Antibody?
A: The main contraindication is a known hypersensitivity to the product or any of its components.
Q6: What are the most common side effects of Rabies Human Monoclonal Antibody?
A: Common side effects include local injection site reactions (pain, swelling, redness), and systemic reactions like mild fever, headache, and muscle aches.
Q7: Can Rabies Human Monoclonal Antibody be given to pregnant or breastfeeding women?
A: Data regarding safety during pregnancy and breastfeeding are limited. It should be used only if the potential benefits outweigh the potential risks.
Q8: How soon after exposure should Rabies Human Monoclonal Antibody be administered?
A: It should be given as soon as possible after a suspected rabies exposure.
Q9: Does Rabies Human Monoclonal Antibody interact with other medications?
A: It may potentially interfere with the immune response to live attenuated vaccines. Consult relevant guidelines for further information.
