Amoxicillin-clavulanate is the standard first-line antibiotic for cat bites, recommended by both the Infectious Diseases Society of America and the Merck Manual for both prevention and treatment of infection. Cat bites carry a high infection risk, with 28% to 80% becoming infected, so getting the right antibiotic early matters more here than with most other animal bites.
Why Cat Bites Are Uniquely Dangerous
Cat teeth are narrow and sharp, designed to puncture deeply rather than tear. Unlike the broader wounds from a dog bite, a cat bite creates a small entry point that can push bacteria deep into tissue, sometimes reaching joint capsules or the thin membrane covering your bones. The skin then closes over the wound quickly, trapping bacteria in an ideal environment for infection.
The main culprit is a bacterium called Pasteurella multocida, found in roughly 75% of infected cat bite wounds. This organism thrives in the low-oxygen conditions of a deep puncture wound and can cause redness, swelling, and intense pain within 12 to 24 hours. For comparison, only about 50% of dog bite infections involve the same bacterium, and dog bites overall become infected far less often (3% to 18% of the time).
Why Amoxicillin-Clavulanate Works Best
Amoxicillin-clavulanate combines a standard penicillin-type antibiotic with a second compound that prevents bacteria from breaking it down. This combination is specifically effective against Pasteurella multocida and the mix of other bacteria commonly found in a cat’s mouth, including several species that grow in oxygen-poor environments deep in puncture wounds. Most other common antibiotics miss one or more of these organisms, which is why a broad-spectrum option is important here.
If you’re taking this antibiotic to prevent an infection before one develops, the typical course is 3 days. If an infection has already set in, expect a course of 5 to 7 days. Your prescriber will determine the right duration based on the wound’s severity and location.
Alternatives If You’re Allergic to Penicillin
For adults who can’t take penicillin-based antibiotics, a fluoroquinolone (such as ciprofloxacin) is the standard alternative. For children, options include clarithromycin or clindamycin. These alternatives still cover the key bacteria in cat bite wounds, though the first-line option remains preferred when there’s no allergy.
When Antibiotics Are Recommended
Not every cat bite automatically requires antibiotics, but a large portion do. The Infectious Diseases Society of America recommends early preventive antibiotics for 3 to 5 days in several specific situations: if the bite is on the hand or face, if the wound is moderate to severe, if the bite may have reached bone or a joint, or if you have a weakened immune system, lack a spleen, or have advanced liver disease. Swelling in the area of the bite also raises the risk.
In practice, many clinicians treat all cat bites with preventive antibiotics because puncture wounds are so difficult to assess visually and the infection rate is so high. Hand bites are especially concerning. The tendons, joints, and thin tissue layers in the hand give bacteria easy paths to spread, and infections there can cause permanent damage if not treated quickly.
Timing Matters
How quickly you seek care after a cat bite affects your infection risk significantly. Waiting more than 6 to 12 hours for bites on the arms or legs is considered a delayed presentation and raises the chance of infection. For bites on the face, the window is slightly longer, at 12 to 24 hours, partly because blood flow to the face helps fight infection more effectively.
Before you get to a clinic, the single most important thing you can do is wash the wound thoroughly with soap and water. This simple step physically removes bacteria from the wound and reduces the bacterial load before antibiotics even enter the picture. If you have povidone-iodine solution at home, irrigating with that can help further.
Beyond Antibiotics: Tetanus and Rabies
Your provider will also evaluate whether you need a tetanus booster based on your vaccination history and the type of wound. If you haven’t had a tetanus shot in the last five years and the wound is deep or contaminated, a booster is typically given.
Rabies is rare from domestic cats in the United States, but the risk isn’t zero. If the cat was a stray, behaving unusually, or its vaccination status is unknown, your provider or local public health department will perform a risk assessment. If rabies exposure is a possibility, post-exposure treatment involves thorough wound cleaning followed by a series of four vaccine doses over two weeks. People who are immunocompromised receive a fifth dose on day 28.
Signs of Infection to Watch For
Even with antibiotics, you should monitor the bite closely for the first several days. Pasteurella infections can progress fast, sometimes within hours. Watch for increasing redness spreading outward from the wound, swelling that worsens rather than improving, warmth at the site, pus or cloudy drainage, red streaks extending up your arm or leg, or fever. Infections from cat bites on the hand can cause stiffness and difficulty moving your fingers, which signals that deeper structures may be involved and needs urgent attention.