Which of the following is NOT an antibiotic?

Ibuprofen is not classified as an antibiotic; it is a nonsteroidal anti-inflammatory drug (NSAID) used primarily to relieve pain, reduce inflammation, and lower fever. Unlike antibiotics, which are specifically designed to inhibit bacterial growth or kill bacteria, ibuprofen does not have any antibacterial properties and does not treat infections caused by bacteria.

In contrast, amoxicillin, penicillin, and tetracycline are all antibiotics that function to combat bacterial infections. Amoxicillin and penicillin are both part of the penicillin family and are widely used to treat various infections. Tetracycline is a broad-spectrum antibiotic that targets a wide range of bacteria. Thus, identifying ibuprofen as the non-antibiotic option highlights its distinct role in medicine separate from bacterial infection treatment.