Figure 3. Average number of morphine doses required in children who received acetaminophen 0, 20, 40, or 60 mg/kg rectally. Acetaminophen had a clear morphine-sparing effect: The number of morphine doses was smaller with the greater acetaminophen doses. Single asterisk denotes difference from the 0-mg/kg group, and double asterisk denotes significant difference from 0- and 20-mg/kg groups. Bars indicate SEM.