Intravenous Lidocaine Versus Morphine for Severe Pain in the ED

Objective: The purpose of this pilot study is to determine the analgesic efficacy of intravenous lidocaine versus morphine for the treatment of severe pain in the emergency department (ED).

Study design: Open-label, randomized, controlled pilot trial. Participants: Investigators and research assistants will recruit patients ≥18 years old with severe pain (NRS ≥7) and an anticipated stay in the emergency department ≥1 hour. A sample size calculation was performed and 32 patients will be enrolled.

Intervention: After a trained research assistant obtains written informed consent, eligible participants will be randomized to the intravenous lidocaine or morphine arms of the study. In the intravenous lidocaine arm, patients will receive IV lidocaine (75 mg if <50kg, 100 mg if 50 - 100 kg, and 150 mg if >100 kg) over 10 minutes in a 100 mL normal saline minibag followed by a 50 minute IV lidocaine drip (75 mg if <50kg, 100 mg if 50 - 100 kg, and 150 mg if >100 kg). In the morphine arm, the ED provider will choose an appropriate dose of morphine for the patient. At 20 and 40 minutes, the participants will be asked "Would you like additional pain medication?". Participants responding in the affirmative will receive morphine 4 mg IV.

Data collection: The trained research assistant will collect data on the patients' pain scores, side effects, and rescue morphine.

Statistical analysis: Investigators will perform descriptive statistics and compare pain scores and pain relief at each time point with unpaired t-tests.

Inclusion criteria

• Subject has severe pain (NRS ≥7)
• Subject has anticipated ED stay of ≥1 hour

Exclusion criteria

• High acuity trauma patients
• Patients deemed to critically ill by ED provider
• Active psychosis
• Pregnancy
• History of heart block or bradycardia
• Allergy to lidocaine or amide type local anesthetic
• History of seizures