A patient Manoj with severe pain thought to be of gastrointestinal origin received 60 mg of meperidine subsequent to which he developed reaction characterized by tachycardia, hypeension, hyperpyrexia and seizures. He gave the history that he is also taking some medicine for his psychiatric condition. Which of the following drug can be held responsible for this so of reaction?

## Core Concept
The question tests the understanding of drug interactions, specifically the serotonin syndrome, which is a potentially life-threatening condition caused by an excess of serotonin in the central nervous system. This condition can occur when certain medications are taken together.

## Why the Correct Answer is Right
The patient's symptoms, including tachycardia, hypertension, hyperpyrexia, and seizures, following the administration of meperidine, suggest serotonin syndrome. Meperidine is an opioid that can inhibit serotonin reuptake. When taken with certain psychiatric medications that increase serotonin levels (such as selective serotonin reuptake inhibitors, SSRIs), it can lead to serotonin syndrome. Among the options provided, the one that fits as a precipitant of serotonin syndrome when combined with meperidine is an SSRI.

## Why Each Wrong Option is Incorrect
- **Option A:** While certain drugs can cause similar reactions, without specifying the drug, it's hard to directly refute. However, given the context, it's less likely to be directly implicated in serotonin syndrome compared to an SSRI.
- **Option B:** This option might refer to a different class of psychiatric medications. If it's not an SSRI or another serotonin-enhancing drug, it's less likely to cause this reaction with meperidine.
- **Option C:** Similar to Option A, without specifics, it's challenging to directly address. However, if it's not directly related to serotonin reuptake inhibition, it's less likely.
- **Option D:** This option is not provided, but based on the correct answer being , we can infer that is the correct choice.

## Clinical Pearl / High-Yield Fact
A critical clinical pearl is to always inquire about a patient's current medication list, including psychiatric medications, before prescribing new drugs. The combination of meperidine with SSRIs is particularly risky for inducing serotonin syndrome. A classic mnemonic for serotonin syndrome includes the "5 Hs": Hyperthermia, Hypertension, Hyperreflexia, Hypertonia, and Hyperactivity (including seizures).

## Correct Answer: C. Fluoxetine.

✓ Correct Answer: D. Phenelzine