Which antibiotics require administration within 120 minutes prior to incision rather than 60 minutes?

• A. Penicillin only.
• B. All antibiotics.
• C. No antibiotics are required.
• D. Vancomycin or fluoroquinolones.

Answer: (D)

Timing of prophylactic antibiotics is all about getting the drug into the tissues at the moment the incision is made. Most agents are given within 60 minutes before incision so they reach effective levels quickly as the incision starts. But some drugs take longer to infuse and have safety considerations that push the preoperative window to 120 minutes. Vancomycin is infused over a longer period and can cause infusion-related reactions if given too quickly, so it’s started earlier to ensure complete infusion and therapeutic tissue levels by incision. Fluoroquinolones likewise often require longer infusion times and pharmacokinetic preparation, so they’re given 120 minutes beforehand. Therefore, the antibiotics that require administration within 120 minutes prior to incision are vancomycin and fluoroquinolones; penicillin or other agents typically fit the shorter 60-minute window, and the idea that no antibiotics or all antibiotics would apply isn’t correct.