IV Acetaminophen as Adjuvant Analgesic to Hydromorphone - Emergency Department Patients

Phase 3

Completed

Brief Summary: The goal of this randomized clinical trial is to compare the analgesic efficacy and side effect profile of IV acetaminophen as an analgesic adjunctive medication to IV hydromorphone for the treatment of acute pain experienced by patients in the Emergency Department (ED).

Detailed Description: 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. All patients received 1 mg of IV hydromorphone. They were then randomized to receive either 1 g of IV acetaminophen or 100 mL of normal saline placebo. Measures of pain, vital signs, and presence of side effects were obtained immediately before IV hydromorphone was administered. Following receipt of the acetaminophen or placebo these same variables were measured at 15 minute intervals for the next 120 minutes. Additional analgesics were administered if patients requested them. Subsequent care of the patients was at the discretion of the treating attending physician.

Recruitment & Eligibility

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
Systolic blood pressure <100 mmHg
Heart Rate < 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

Arm && Interventions

Group	Intervention	Description
IV hydromorphone and placebo	IV placebo	100 ml IV normal saline administered over 5-10 minutes 1 mg hydromorphone administered over 5-10 minutes
IV hydromorphone and placebo	hydromorphone	100 ml IV normal saline administered over 5-10 minutes 1 mg hydromorphone administered over 5-10 minutes
IV hydromorphone and IV acetaminophen	IV acetaminophen	1000 mg IV acetaminophen administered over 5-10 minutes 1 mg hydromorphone administered over 5-10 minutes
IV hydromorphone and IV acetaminophen	hydromorphone	1000 mg IV acetaminophen administered over 5-10 minutes 1 mg hydromorphone administered over 5-10 minutes

Primary Outcome Measures

Name	Time	Method
Change in Numerical Rating Scale of Pain (NRS) Before Treatment to 60 Minutes After Treatment	Before treatment to 60 minutes after treatment	The between group difference in change in NRS pain scores from before administration of study medications to 60 minutes post administration of study medications. The NRS is a previously validated and reproducible measure of pain intensity ranging from 0 = no pain, to 10 = worst possible pain. Higher values indicate more pain relief from before treatment to 60 minutes after treatment

Secondary Outcome Measures

Name	Time	Method
Percentage of Patients Who Received Additional Pain Medication Within 60 Minutes of Administration of Study Medication	Baseline to 60 minutes post-baseline	Difference in percentage of patients who received additional pain medication within 60 minutes of administration of study medication in the two arms of the study
Percentage of Patients Who Received Additional Pain Medication Between 61 and 120 Minutes After Administration of Study Medications	61 to 120 minutes post-baseline	Difference in percentage of patients who received additional pain medication between 61 and 120 minutes after administration of study medication by study group
Percentage of Patients Who Want Additional Analgesics	Immediately after administration of study medication to 120 minutes after administration of study medication	Number of patients who answer "yes" to question: "Do you want more pain medication" divided by number of patients