What should be injected if a rat bites? - briefly
Administer a tetanus toxoid booster promptly, and evaluate the need for rabies post‑exposure prophylaxis based on the bite circumstances and local rabies risk.
What should be injected if a rat bites? - in detail
When a rat bite occurs, immediate medical intervention should include a combination of wound management, antimicrobial therapy, and prophylaxis against tetanus and, when indicated, rabies.
The wound must be irrigated thoroughly with saline or clean water to remove debris and reduce bacterial load. After cleaning, the bite site should be examined for depth, tissue involvement, and signs of infection.
Pharmacologic measures
- Tetanus prophylaxis – administer tetanus toxoid (Tdap or Td) if the patient’s immunization record shows a gap of more than five years since the last dose, or if the vaccination status is unknown. In cases of severe or contaminated wounds, give tetanus immune globulin (250 IU intramuscularly) in addition to the toxoid.
- Rabies prevention – assess the rat’s health and the exposure circumstances. If the animal is wild, shows abnormal behavior, or its rabies status cannot be verified, initiate the rabies post‑exposure prophylaxis schedule: one dose of human rabies immune globulin (20 IU/kg) infiltrated around the wound, followed by a series of rabies vaccine injections on days 0, 3, 7, and 14 (and day 28 for immunocompromised patients).
- Antibiotic therapy – start broad‑spectrum coverage targeting Streptococcus, Staphylococcus, and Pasteurella species, which are common in rodent oral flora. A recommended regimen is amoxicillin‑clavulanate 875 mg/125 mg orally twice daily for 5–7 days. For patients allergic to penicillins, use doxycycline 100 mg orally twice daily or a fluoroquinolone such as ciprofloxacin 500 mg twice daily, adjusted for renal function.
Follow‑up
- Re‑evaluate the wound after 24–48 hours for signs of cellulitis, abscess formation, or systemic infection.
- Verify completion of the tetanus series and rabies vaccine schedule, documenting each dose.
- Counsel the patient on signs of infection (increased redness, swelling, fever) and advise immediate return to care if they develop.
These steps provide comprehensive protection against the most serious complications of a rat bite.