RESULTS Sixteen full-length articles from 9 countries published between 2005 and 2010 met our inclusion criteria and were fully analyzed (Table 1). Overall, there were 1,464 patients included in the 16 RCTs including a total of 780 patients who received IV acetaminophen. The median sample size including control groups equaled 54 patients (average 68, range 25 to 165), with median follow-up of 1 day (average 1.54 days, range 1 hour to 7 days). Four of the 16 articles had 3 arms in the study: a placebo group, an IV acetaminophen group, and an active comparator or a second IV acetaminophen group with different timing of dosing. One article had 4 arms,