The formulary status of IV acetaminophen can be controversial, given that it is an expensive medication without consistent evidence of benefit on clinically meaningful patient outcomes such as reducing the length of hospital stay or ileus.
One argument for keeping IV acetaminophen on formulary is for use in critically ill patients whose hemodynamics might be improved by the antipyretic effect of acetaminophen.
Elevated temperature increases oxygen demand, which can be exacerbated by conditions such as sepsis, respiratory failure, and cardiac disease. Acetaminophen would theoretically reduce oxygen demand in patients with fever.
However, a six patient observational study published in 2013 suggested that IV acetaminophen worsens cardiac output and systemic vascular resistance.
In addition, a prospective observational study of 160 critically ill patients who received IV acetaminophen published in 2016 in Critical Care Medicine found that 51.9% of patients experienced hypotension after receiving IV acetaminophen.
The nadir mean arterial pressure occurred within 15 to 71 minutes after receiving IV acetaminophen and ranged from 54 to 74 mmHg. Surprisingly, changes in body temperature were not correlated with changes in mean arterial pressure.
Among the patients that experienced hypotension, 34.9% required a therapeutic intervention to address the hypotension.
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