For IE prophylaxis, amoxicillin should be given how long before the dental procedure?

• A. 30-60 minutes after the procedure.
• B. 30-60 minutes before the procedure.
• C. 2-4 hours before the procedure.
• D. During the procedure.

Answer: (B)

Prophylaxis works best when the antibiotic is in the bloodstream at the moment the dental procedure causes bacteremia. Amoxicillin is absorbed quickly and reaches peak serum levels within about an hour, so giving it 30–60 minutes before the procedure ensures protective levels are present during gingival manipulation when bacteria can enter the bloodstream. If given earlier, levels may wane by the time bacteremia occurs; giving it after or during the procedure misses the window and is less effective. Therefore, a pre-procedure dose about 30–60 minutes before the procedure is the recommended approach.