Which of the following is NOT an example of an analgesic?

Penicillin is not classified as an analgesic because it serves a different purpose in medicine. Analgesics are medications specifically designed to relieve pain, and they work through various mechanisms to achieve this effect.

Tylenol (acetaminophen) and aspirin are both analgesics; they are used to reduce pain and reduce fever (in the case of Tylenol) or to reduce inflammation (in the case of aspirin). Meperidine, also known as Demerol, is an opioid analgesic used to treat moderate to severe pain.

Penicillin, on the other hand, is an antibiotic that is used to treat infections caused by bacteria. It does not have pain-relieving properties and is used to combat infections rather than manage or alleviate pain, making it distinctly different from the other substances listed.