Which medication is classified as an opioid analgesic?

Duragesic is classified as an opioid analgesic because it contains fentanyl, which is a potent synthetic opioid used for pain management. Opioid analgesics work by binding to specific receptors in the brain and nervous system to reduce the perception of pain. They are typically prescribed for moderate to severe pain and can be particularly useful for patients who have developed a tolerance to other pain medications.

Humalog is an insulin used for diabetes management, Vibramycin is an antibiotic primarily used to treat bacterial infections, and Diovan is an antihypertensive medication utilized for managing high blood pressure. Each of these medications serves a different therapeutic purpose that does not include the management of pain through an opioid mechanism. Therefore, Duragesic stands out as the correct answer in this context.