Which of the following medications can falsely elevate 5-HIAA levels?

Naproxen can falsely elevate 5-Hydroxyindoleacetic acid (5-HIAA) levels, which is a metabolite of serotonin. In clinical practice, it is critical to be aware of medications that may interfere with serotonin metabolism or its breakdown, particularly when diagnosing conditions such as carcinoid syndrome, where 5-HIAA is often measured in a 24-hour urine collection.

Naproxen, a nonsteroidal anti-inflammatory drug (NSAID), is known to potentially influence serotonin levels due to its effects on the gastrointestinal tract and the enterochromaffin cells, which can alter the way serotonin is metabolized and excreted. This physiological interaction may lead to an increase in 5-HIAA levels in the urine, thus complicating the interpretation of test results and potentially leading to misdiagnosis if not recognized.

Other medications on the list, such as ibuprofen, acetaminophen, and aspirin, generally do not have the same level of association with significant changes in 5-HIAA levels and are less likely to interfere with serotonin metabolism in the way that naproxen does. Therefore, understanding the biochemical processes and the influence of specific medications is essential for accurate diagnostic evaluation regarding serotonin-related disorders.