This opioid is discouraged due to large histamine release, toxic metabolite that may cause seizures, and can be fatal if given with an MAOI.

• A. Demerol (Meperidine)
• B. Morphine sulfate
• C. Fentanyl
• D. Hydromorphone

Answer: (A)

Meperidine stands out because of a dangerous combination of properties: it produces a toxic metabolite, normeperidine, that can accumulate and provoke CNS excitation and seizures, especially in patients with kidney impairment or when given repeatedly. It also has a notable histamine-releasing effect, which can cause hypotension and pruritus. Most importantly for safety, combining it with a monoamine oxidase inhibitor can lead to a potentially fatal reaction, including severe agitation, hyperthermia, and seizures. Other opioids like morphine, fentanyl, and hydromorphone do not have the same combination of a neurotoxic metabolite and dangerous MAOI interaction, making this opioid the one to avoid.