Administrative

Intravenous lidocaine will be given at a dose of 2 mg/kg intravenously to patients in the emergency department with a diagnosis of acute abdominal pain. Its efficacy will be compared to 1 mg of intravenous hydromorphone, with a primary endpoint of mean improvement of pain at 90 minutes.

Abdominal pain is a common chief complaint for patients presenting to the emergency department (ED) in the United States. Intravenous opioids are commonly used to treat acute abdominal pain in the ED. These medications are highly efficacious and, when used in a monitored setting such as the ED, extremely safe. Use of opioids has fallen out of favor because of a spike in opioid-related overdose deaths throughout the United States. While use of opioids in the ED is unlikely to contribute to outpatient opioid deaths, minimizing the use of opioids in the ED will contribute to an opioid free culture, in which opioids are used only when absolutely necessary. A variety of different types of medications can be used in lieu of opioids. One such medication, intravenous lidocaine, has been used extensively for neuropathic pain, in the peri- and post-operative surgical setting, the cardiac care unit, and most recently in the emergency department.

Intravenous lidocaine has long been used to treat pain. In publications dating back to 1980, intravenous lidocaine has been shown to be an effective treatment for neuropathic pain. In the postoperative setting, intravenous lidocaine decreased pain and decreased the need for opiates. More recently, emergency medicine investigators in Iran demonstrated that intravenous lidocaine decreased pain associated with renal colic and limb ischemia. An ED-based study in the United States showed comparable efficacy between morphine and intravenous lidocaine when used for acute pain. Most recently, a prospective RCT showed 120 mg of intravenous lidocaine was efficacious for abdominal pain, albeit not as effective as 1 mg of hydromorphone. However, a subgroup analysis showed that when lidocaine was dosed at 2 mg/kg, it was equally as effective as hydromorphone.

Over the years, intravenous lidocaine has been used for a variety of indications including arrhythmia prophylaxis in patients with acute coronary syndromes. Known side effects of intravenous lidocaine range from transient neurological symptoms (dizziness, paresthesias), to cardiac dysrhythmias and seizure. To date, no deaths have been attributed to its use for treating pain, and the only documented significant complication was due to an unintentional overdose when a patient received ten times the normal dose. All reported side effects in pain patients have been transient and resolved by either stopping the drug, decreasing the infusion rate or by observation alone. Additionally, doses of 2 mg/kg have been tolerated well in the outpatient setting, operating room and ED without any serious side effects. Thus, intravenous lidocaine is an emerging medication for safe and rapid relief of pain, has no known addictive properties, and creates a potential for a pain practice paradigm shift in the United States.

We therefore propose a randomized, double blind, comparative efficacy trial to address the following aim:

To determine if a 2 mg/kg dose of intravenous lidocaine is as equally efficacious as a single dose of 1 mg intravenous hydromorphone for acute abdominal pain in the emergency department.

Inclusion Criteria:

• Must be a patient in the emergency department (ED)
• Must have acute abdominal pain, defined as abdominal or flank pain of a duration of 7 days or less
• Predicted treatment must include the use of an intravenous opiate

Exclusion Criteria:

• Cardiac conduction system impairment (QTc duration > 0.5s, QRS duration > 0.12s, PR interval <0.12s or > 0.2s)
• Known renal (CKD >2) or liver disease (Childs-Pugh B or greater)
• Hemodynamically instability, defined by the attending physician
• Pregnant or breastfeeding
• Have a known allergy to either medication
• Used of prescription or illicit opioids within the previous week
• Patients with a chronic pain disorder, defined as use of any analgesic medication on more days than not during the four weeks preceding the acute episode of pain

Subjects were monitored for the first 180 minutes they were in the emergency department. They were followed up to 7 days later.

No statistical analysis was done due to enrolling only 4 subjects before the trial was terminated.