Inclusion Criteria:

• Provide written informed consent prior to participation in the Study
• Be at least 18 years of age and weigh at least 41 kg
• Be anticipated by the Investigator to require multi-day (target is five days) use of IV treatment either because of having a "nothing by mouth" (NPO) status having a medical condition that makes oral intake difficult having a medical condition that requires IV treatment
• Be willing to undergo 5 days of treatment with IV acetaminophen for the treatment of pain or fever (defined as a core temperature greater than or equal to 38 degrees celsius). Note that Subjects have a slightly less than 15% chance (one in seven) of being assigned to the Control Group and receiving standard of care treatment, but no IV APAP.
• Have the ability to read and understand the Study procedures and have the ability to communicate meaningfully with the Study Investigator and staff
• If a female of child bearing potential, have a negative pregnancy test within 48 hours of randomization

Exclusion Criteria:

• Has a significant medical disease, laboratory abnormality or condition that, in the Investigator's judgment, could compromise the Subject's welfare or would otherwise contraindicate Study participation
• Is expected to have difficulty in communicating with the Study staff or completing Study requirements (including follow up visits)
• Has known hypersensitivity to acetaminophen or the inactive ingredients (excipients) of IV acetaminophen or any contraindication to receiving acetaminophen
• Has impaired liver function, e.g., ALT greater than or equal to 3 times the upper limit of normal (ULN), bilirubin greater than or equal to 3 times ULN, known active hepatic disease (e.g., hepatitis), evidence of clinically significant chronic liver disease or other condition affecting the liver (e.g., alcoholism as defined by DSM-IV, cirrhosis or chronic hepatitis)
• Has participated in an interventional clinical Study (investigational or marketed product) within 30 days of Study entry