Randomized Trial of Intravenous Lidocaine Versus Hydromorphone for Acute Abdominal Pain in the Emergency Department

Abstract

We compared the efficacy and safety of intravenous lidocaine to that of hydromorphone for the treatment of acute abdominal pain in the emergency department. This was a randomized, double blind clinical trial conducted in two EDs in the Bronx, NY. Adults weighing 60–120 kg were randomized to receive 120 mg of IV lidocaine or 1 mg of IV hydromorphone. 30 minutes after administration of the first dose of study drug, participants were asked if they needed a second dose of the investigational medication to which they were randomized. Patients were also stratified based on clinical suspicion of nephrolithiasis. The primary outcome was improvement in 0–10 pain scores between baseline and 90 minutes. An important secondary outcome was need for “off-protocol” parenteral analgesics, including opioids or non-steroidal anti-inflammatory drugs. We enrolled 154 patients of whom 77 received lidocaine and 77 received hydromorphone. By 90 minutes, patients randomized to lidocaine improved by a mean of 3.8 points on the 0–10 scale, while those randomized to hydromorphone improved by a mean of 5.0 points (mean difference 1.2, 95% CI: 0.3, 2.2). Need for off-protocol “rescue” analgesics occurred in 39/77 (51%) of lidocaine patients and 20/77 (26%) hydromorphone patients (95%CI for difference of 25%: 10, 40%). Adverse events were comparable between groups. Among the subset of 22 patients with nephrolithiasis, lidocaine patients reported a mean improvement of 3.4 points on the pain scale, while hydromorphone patients reported a mean improvement of 6.4 points (mean difference 3.0, 95% CI: 0.5 to 5.5). IV hydromorphone was superior to IV lidocaine, both for general abdominal pain and a subset with nephrolithiasis. A majority of patients randomly allocated to lidocaine required additional analgesia.