Acetaminophen has limited antipyretic activity in critically ill patients

Fever occurs commonly in the critically ill patients and may adversely affect outcome. Acetaminophen is one of the most commonly used antipyretic agents in the intensive care unit; however, there is little evidence that it is effective in this population. The objective of this study was to analyze the antipyretic activity of acetaminophen in critically ill patients.

We performed a retrospective study of medical intensive care unit and surgical intensive care unit patients with systemic inflammatory response syndrome and compared the resolution of fever in the presence and absence of acetaminophen treatment by comparing the absolute reduction in body temperature and the rate of cooling over comparable time frames in fevers that were untreated and those treated with acetaminophen.

We analyzed 166 febrile episodes (body temperature, >38 degrees C) in 59 patients with systemic inflammatory response syndrome without cancer, neurologic disease, or liver disease. Acetaminophen was administered for 88 of 166 fevers. Febrile episodes in which other antipyretic drugs or external cooling were administered were excluded. The response to acetaminophen was variable, but the absolute temperature reduction was slightly higher (mean, 0.86 versus 0.56 degrees C; P = .0362), and the cooling rate was slightly more rapid (mean, 0.20 versus 0.13 degrees C per hour; P = .0152) in acetaminophen-treated versus untreated fevers. There were no obvious differences between the most and least responsive patients.

We conclude that acetaminophen has significant albeit modest antipyretic activity in critically ill patients.