IV Acetaminophen as Adjuvant Analgesic to Hydromorphone - Emergency Department Patients

Multimodal treatment of pain is a commonly used strategy to control pain by combining
analgesics with different and complementary mechanisms of action. Oral acetaminophen combined
with opioids is a mainstay of treatment of mild to moderate pain, while the use of IV opioids
is the standard for treatment of severe pain in the Emergency Department. An IV formulation
of acetaminophen is widely used in Europe and has recently been approved in the US. It has
been studied for treatment of acute post-operative pain and renal colic. This randomized
trial was designed to assess the effectiveness of the combination of IV acetaminophen and IV
hydromorphone as a strategy to provide more effective treatment of acute severe pain in the
Emergency Department with the possibility of reducing opioid consumption.

Inclusion Criteria:

- Pain with onset within 7 days of the ED visit

- ED attending physician's judgment that the patient's pain warrants IV opioids.

- ED attending physician's judgment that the patient has capacity to provide informed
consent.

- ED attending physician's judgement that patient is not a chronic user of opioids or
acetaminophen

- Patients must be able to understand English or Spanish.

Exclusion Criteria:

- Use of opioids or tramadol within past 24 hours.

- Use of acetaminophen or non-steroidal anti-inflammatory medication within the previous
8 hours.

- Prior adverse reaction to opioids or acetaminophen.

- Chronic pain syndrome: frequently recurrent or daily pain for at least 3 months;
examples of chronic pain syndromes include sickle cell anemia, osteoarthritis,
fibromyalgia, and peripheral neuropathies.

- Medical condition that might affect metabolism or opioid analgesics or acetaminophen
such as hepatitis, renal insufficiency or failure, hypo- or hyper-thyroidism,
Addison's or Cushing's disease

- Pregnant or breastfeeding

- Alcohol intoxication: the presence of alcohol intoxication as judged by the treating
physician or nurse

- Not at risk of suicide assessed by triage nurse

- SBP <100 mmHg

- HR < 60/min

- Oxygen saturation < 95% on room air:

- Use of monoamine oxidase (MAO) inhibitors in past 30 days

- Use of transdermal pain patches

- Taking any medication that might interact with one of the study medications, such as a
selective serotonin reuptake inhibitor (SSRI) or tricyclic anti-depressants,
antipsychotics, anti-malarial medications (quinidine or halofantrine), amiodarone or
dronedarone, diphenhydramine, celecoxib, ranitidine, cimetidine, ritonavir,
terbinafine or St. John's Wort.

- Patients who have been previously enrolled in this same study