Question 1

When does Day 1 of an antibiotic course start?

Accepted Answer

Day 1 is the day the **first dose is administered**, not the day the order is placed. IV-to-PO transitions don't restart the count — Day 1 IV followed by Day 2 PO is therapy day 2, not day 1 of PO.

Question 2

How long should antibiotics be given for community-acquired pneumonia?

Accepted Answer

Current guidelines support **5 days** for CAP if the patient is clinically stable on day 5. Other shorter-course regimens with strong evidence: **4 days** for intra-abdominal infection (after source control) and **7 days** for uncomplicated pyelonephritis.

Question 3

How are days counted for S. aureus bacteremia?

Accepted Answer

For *S. aureus* bacteremia, the 14-day course (uncomplicated) is counted from the **first negative blood culture**, not from antibiotic start. This is one of the few infections where day-counting deviates from the standard "day 1 = first dose" rule.

Question 4

What's the difference between days of therapy (DOT) and length of therapy (LOT)?

Accepted Answer

**Length of therapy (LOT)** is calendar days the patient receives any antibiotic. **Days of therapy (DOT)** counts each agent separately — a patient on vancomycin and cefepime for 5 days has a LOT of 5 but a DOT of 10. Antimicrobial stewardship programs typically track DOT.

Antibiotic Days-of-Therapy

Related