How long should antibiotics take to work for an infected insect bite?

Antibiotics: Usually antibiotics takes 24-48 hours to help for an infected insect bite. The duration of effectiveness depends on severity of infection, organism, route of antibiotic use, associated complication.

In most cases: One should see noticeable improvement in 3-5 days of taking an oral antibiotic for an infection. It is prudent to finish the course of the antibiotic which is typically 10-14 days unless taking something like zithromax which would be 5 days, so one does not cause antibiotic resistance to develop.