Usage
Rabies vaccine, Human is prescribed for the prevention of rabies infection. It is used for both pre-exposure prophylaxis in individuals at high risk of exposure (e.g., veterinarians, animal handlers, laboratory workers, travelers to rabies-endemic areas) and post-exposure prophylaxis following a potential rabies exposure (e.g., bite, scratch, or lick from a potentially rabid animal).
Pharmacological classification: Vaccine (active immunizing agent)
Mechanism of action: Stimulates active immunity by inducing the production of rabies virus-neutralizing antibodies.
Alternate Names
Rabies vaccine may also be referred to as Human Diploid Cell Vaccine (HDCV) or Purified Chick Embryo Cell Vaccine (PCEC), depending on the specific formulation. Several brands are available.
How It Works
Pharmacodynamics: The vaccine mimics a rabies infection, prompting the immune system to produce antibodies against the rabies virus. These antibodies neutralize the virus, preventing it from spreading and causing disease.
Pharmacokinetics: The vaccine is administered intramuscularly (IM) or intradermally (ID). IM injection into the deltoid muscle (adults and older children) or anterolateral thigh (infants and young children) is preferred. The gluteal muscle should be avoided due to potential for reduced immunogenicity. Following injection, the vaccine components are processed by the immune system, leading to antibody production. Antibody titers peak within 2-4 weeks after completion of the primary series. Elimination pathways and metabolism of the vaccine components are not typically studied in the same way as traditional drugs.
Mode of action: The vaccine introduces inactivated rabies virus into the body. This inactivated virus is recognized by antigen-presenting cells, which then activate B lymphocytes. The B lymphocytes differentiate into plasma cells that produce rabies-specific antibodies.
Dosage
Standard Dosage
Adults: Pre-exposure prophylaxis: Two 1.0 mL doses IM, administered into the deltoid muscle, seven days apart. Post-exposure prophylaxis (for unvaccinated individuals): Four 1.0 mL doses IM, administered on days 0, 3, 7, and 14, along with Rabies Immune Globulin (RIG) on day 0.
Children: Pre-exposure prophylaxis: Same as adult dosing. Post-exposure prophylaxis: Same as adult dosing, but the IM injection may be administered into the anterolateral thigh muscle.
Special Cases:
- Elderly Patients: May have a diminished immune response. Antibody titers should be checked, and booster doses might be necessary.
- Patients with Renal Impairment: No specific dose adjustment is typically required.
- Patients with Hepatic Dysfunction: No specific dose adjustment is typically required.
- Patients with Comorbid Conditions: Immunosuppressed individuals may have a reduced response to the vaccine. Additional doses or RIG may be considered.
Clinical Use Cases
The dosages outlined above apply to general clinical use cases for pre- and post-exposure prophylaxis. Specific clinical use cases like intubation, surgical procedures, mechanical ventilation, and ICU use do not generally necessitate rabies vaccination unless a potential rabies exposure occurs in these settings. In emergency situations involving animal bites, standard post-exposure prophylaxis should be followed.
Dosage Adjustments
Dose adjustments may be needed based on factors like immune status. For example, immunocompromised individuals may require additional vaccine doses or RIG. Pregnant and breastfeeding women should receive post-exposure prophylaxis if exposed to rabies.
Side Effects
Common Side Effects
Pain, redness, swelling, or itching at the injection site, headache, nausea, muscle aches, dizziness, fever, malaise.
Rare but Serious Side Effects
Allergic reactions (e.g., hives, difficulty breathing, swelling of the face, lips, or throat), Guillain-Barré syndrome.
Long-Term Effects
No long-term side effects specifically associated with rabies vaccines are commonly reported.
Adverse Drug Reactions (ADR)
Severe allergic reactions, neurological complications (rare).
Contraindications
Severe allergic reaction to a previous dose of rabies vaccine or any of its components.
Drug Interactions
Immunosuppressive drugs (e.g., corticosteroids) can reduce the immune response to the vaccine.
Pregnancy and Breastfeeding
Pregnancy is not a contraindication to post-exposure prophylaxis, as rabies is a fatal disease. While pre-exposure prophylaxis is generally delayed until after pregnancy, it can be administered if there is a substantial risk of exposure. The vaccine is considered safe for breastfeeding mothers.
Drug Profile Summary
- Mechanism of Action: Stimulates the production of rabies virus-neutralizing antibodies.
- Side Effects: Injection site reactions (pain, redness, swelling), headache, nausea, muscle aches, fever.
- Contraindications: Severe allergy to previous dose or vaccine component.
- Drug Interactions: Immunosuppressants.
- Pregnancy & Breastfeeding: Safe for post-exposure prophylaxis in both pregnancy and breastfeeding.
- Dosage: See detailed section above.
- Monitoring Parameters: Antibody titers (in certain situations, e.g., immunocompromised individuals).
Popular Combinations
Rabies vaccine is often administered with Rabies Immune Globulin (RIG) as part of post-exposure prophylaxis in unvaccinated individuals.
Precautions
Standard precautions for vaccine administration should be followed. Screen for allergies to vaccine components. Monitor for adverse reactions. In immunocompromised patients, antibody titers should be assessed after vaccination.
FAQs (Frequently Asked Questions)
Q1: What is the recommended dosage for Rabies vaccine, Human?
A: See detailed dosage section above.
Q2: Who should receive pre-exposure rabies prophylaxis?
A: Individuals at high risk of exposure, such as veterinarians, animal handlers, laboratory workers, and travelers to rabies-endemic areas.
Q3: What should be done if a person is bitten by a potentially rabid animal?
A: Immediately wash the wound thoroughly with soap and water and seek medical attention for post-exposure prophylaxis.
Q4: Can pregnant women receive the rabies vaccine?
A: Yes, especially for post-exposure prophylaxis, as rabies is a fatal disease.
Q5: What are the common side effects of the rabies vaccine?
A: Common side effects include injection site reactions, headache, nausea, muscle aches, and fever.
Q6: How long does immunity last after completing the primary rabies vaccination series?
A: Generally considered to provide protection for at least three years for the pre-exposure two-dose series. Post-exposure vaccination should be followed as directed by the treating physician.
Q7: Is the rabies vaccine safe for children?
A: Yes, the rabies vaccine is safe for children and is administered using age-appropriate dosing and injection sites.
Q8: What are the contraindications to receiving the rabies vaccine?
A: A history of severe allergic reaction to a previous dose of rabies vaccine or any of its components.
Q9: What is the role of Rabies Immune Globulin (RIG)?
A: RIG provides immediate passive immunity and is used in conjunction with the rabies vaccine for post-exposure prophylaxis in individuals who have not previously been vaccinated against rabies.
