In patients taking which type of medication is Demerol contraindicated?

Demerol, or meperidine, is a potent opioid analgesic that is contraindicated in patients taking MAO inhibitors (MAOIs) due to the risk of severe interactions. MAOIs, which are typically used as antidepressants, inhibit the metabolism of certain neurotransmitters. When combined with Demerol, this can lead to dangerous reactions such as serotonin syndrome and prolonged sedation or respiratory depression due to increased opioid effects.

The mechanism behind this contraindication is that meperidine can increase the levels of serotonin. In patients taking MAOIs, where serotonin is not effectively broken down, this accumulation can result in a critical condition characterized by increased heart rate, high blood pressure, hyperthermia, and altered mental status.

Other medications listed, such as barbiturates, NSAIDs, and acetaminophen, do not pose the same life-threatening risk when combined with Demerol, making the combination of Demerol and MAOIs particularly concerning due to the serious neuropharmacological effects. Thus, understanding the specific contraindications associated with different classes of medications is crucial for patient safety in the context of sedation and pain management.