IV Acetaminophen as an Analgesic Adjunct

Inclusion Criteria:

• Acute (less than 1 week in duration) severe pain necessitating use of intravenous (IV) opioids in the judgement of the treating attending physician

Exclusion Criteria:

• Use of other opioids or tramadol within past 24 hours: to avoid introducing assembly bias related to recent opioid use, since this may affect baseline levels of pain and need for analgesics.
• Prior adverse reaction to hydromorphone, morphine, or acetaminophen.
• Chronic pain syndrome: frequently recurrent or daily pain for at least 3 months results in modulation of pain perception which is thought to be due to down-regulation of pain receptors. Examples of chronic pain syndromes include sickle cell anemia, osteoarthritis, fibromyalgia, and peripheral neuropathies.
• Alcohol intoxication: the presence of alcohol intoxication as judged by the treating physician may alter pain perception.
• Systolic Blood Pressure (SBP) <100 mm Hg: Opioids can produce peripheral vasodilation that may result in orthostatic hypotension.
• Heart Rate (HR) < 60/min: Opioids can cause bradycardia.
• Oxygen saturation < 95% on room air: For this study, oxygen saturation must be 95% or above on room air in order to be enrolled.
• Use of monoamine oxidase (MAO) inhibitors in past 30 days: MAO inhibitors have been reported to intensify the effects of at least one opioid drug causing anxiety, confusion and significant respiratory depression or coma.
• Patients using transdermal pain patches