Intravenous Lidocaine Provides Similar Analgesia to Intravenous Morphine for Undifferentiated Severe Pain in the Emergency Department: A Pilot, Unblinded Randomized Controlled Trial.

OBJECTIVES: We compared the analgesic effects of intravenous (IV) lidocaine and IV morphine for the treatment of severe pain in the emergency department (ED). METHODS: This was a pilot, unblinded randomized controlled study comparing the efficacy of IV lidocaine vs IV morphine for patients aged ≥18 years with severe pain (numerical rating scale [NRS] ≥ 7). Participants were randomized to receive IV lidocaine (75 mg if <50 kg, 100 mg if 50-100 kg, and 150 mg if >100 kg) over 10 minutes, followed by a 50-minute IV lidocaine infusion of the same dose or provider-chosen dose of morphine. Participants were eligible for rescue morphine. The primary outcome was the difference in patients' mean reported pain at 60 minutes. Secondary outcomes included total morphine consumption, patient satisfaction, and side effects. RESULTS: Thirty-two patients were enrolled. The lidocaine arm's mean pain NRS at 60 minutes was 5.1 (95% confidence interval [CI] = 3.3 to 6.8) compared with 4.2 (95% CI = 3.0 to 5.4) in the morphine arm, and the absolute difference was 0.9 (95% CI = -1.2 to 2.9). Among participants in the lidocaine and morphine arms, 13% and 38%, respectively, had side effects. Patient satisfaction was similar in both arms (87% and 88%). Lidocaine arm patients averaged 4.5 mg of IV morphine (95% CI = 3.0 to 6.0) compared with 8.4 mg (95% CI = 6.9 to 9.8) in the morphine arm, an absolute difference of 3.9 mg (95% CI = 1.8 to 5.9). CONCLUSIONS: We found similar pain relief and satisfaction in both study arms. Lidocaine arm participants had fewer side effects and required less morphine. Lidocaine is a potential opioid-sparing analgesic that deserves further study for severe pain in ED patients.

Slow Infusion of Low-dose Ketamine Reduces Bothersome Side Effects Compared to Intravenous Push: A Double-blind, Double-dummy, Randomized Controlled Trial.

OBJECTIVE: We compared the analgesic efficacy and incidence of side effects when low-dose (0.3 mg/kg) ketamine (LDK) is administered as a slow infusion (SI) over 15 minutes versus an intravenous push (IVP) over 1 minute. METHODS: This was a prospective, randomized, double-blind, double-dummy, placebo-controlled trial of adult ED patients presenting with moderate to severe pain (numerical rating scale [NRS] score ≥ 5). Patients received 0.3 mg/kg ketamine administered either as a SI or a IVP. Our primary outcome was the proportion of patients experiencing any psychoperceptual side effect over 60 minutes. A secondary outcome was incidence of moderate or greater psychoperceptual side effects. Additional outcomes included reduction in pain NRS scores at 60 minutes and percent maximum summed pain intensity difference (%SPID). RESULTS: Fifty-nine participants completed the study. A total of 86.2% of the IVP arm and 70.0% of the SI arm experienced any side effect (difference = 16.2%, 95% confidence interval [CI] = -5.4 to 37.8). We found a large reduction in moderate or greater psychoperceptual side effects with SI administration-75.9% reported moderate or greater side effects versus 43.4% in the SI arm (difference = 32.5%, 95% CI = 7.9 to 57.1). Additionally, the IVP arm experienced more hallucinations (n = 8, 27.6%) than the SI arm (SI n = 2, 6.7%, difference = 20.9%, 95% CI = 1.8 to 43.4). We found no significant differences in analgesic efficacy. At 60 minutes, the mean %SPID values in the IVP and SI arms were 39.9 and 33.5%, respectively, with a difference of 6.5% (95% CI = -5.8 to 18.7). CONCLUSION: Most patients who are administered LDK experience a psychoperceptual side effect regardless of administration via SI or IVP. However, patients receiving LDK as a SI reported significantly fewer moderate or greater psychoperceptual side effects and hallucinations with equivalent analgesia.