Intranasal Ketamine Tied to Lower Opioid Use for Limb Trauma Pain in the ED

By Lisa Rapaport

March 23, 2020

(Reuters Health) - Patients treated for acute limb trauma in the emergency department are less likely to receive opioids and other analgesics if they receive intranasal ketamine early in triage, a randomized study suggests.

The double blind trial included 1,102 patients with acute limb pain who received either intranasal ketamine or placebo during triage.

With intranasal ketamine, 17.2% of patients needed opioids for pain and 31.1% needed non-opioid analgesics during their ED visit. With placebo, 26.5% of patients needed opioids and 39.6% needed non-opioid analgesics, researchers report in the Clinical Journal of Pain.

"Intranasal ketamine given in the triage area was followed by a good pain relief and a significant decrease in the use of rescue opioids," said co-author Dr. Bel Haj Ali Khaoula of Fattouma Bourguiba University Hospital in Monastir, Tunisia.

"By reducing the need for opioids, patients are spared of their multiple side effects such as hypoxia and hypotension commonly observed with opioids use in particular when they are administered repeatedly to patients with acute pain," Khaoula said by email.

Ketamine is commonly used for dissociative anesthesia and procedural sedation, Khaoula noted.

Some studies have demonstrated that ketamine can reduce opioid consumption in postoperative pain but there is still debate regarding the place of the use and the safety of ketamine in the prehospital setting and in the ED, Khaoula added. Moreover, data are limited concerning the use of intranasal ketamine.

A secondary outcome of the study was the proportion of patients discharged from the ER with visual analog scale (VAS) <30, and this was significantly higher in the ketamine group than with placebo. The mean VAS at triage was 73.9 for placebo group and 73.6 for intranasal ketamine group (p=0.63). Eighty percent of patients in intranasal ketamine group were discharged with a VAS lower than 30, compared with 68% in placebo group (p<0.001).

There were significantly more side effects in the intranasal ketamine group. Dizziness, nausea and disorientation were the most-reported in the two groups. Dizziness occurred in 115 patients (20.8%) in the intranasal ketamine group and in 70 patients (12.7%) in the placebo group (p<0.001). Disorientation was also more frequent in the intranasal ketamine group (7.8% vs 0.9; p<0.001).

The study only looked at patients with acute limb trauma, and it isn't clear if results would be similar for other types of pain, the study team writes. Another limitation is that follow-up was performed during the first two hours, while the half-life of ketamine can be up to three hours. It's possible that the ketamine effect would be more prolonged and this would underestimate the intensity of ketamine analgesia, the authors note.

In addition, the study demonstrated that ketamine's opioid sparing effect was predominantly related to tramadol use and not to morphine, which could perhaps be explained by the relatively small doses of ketamine used in this study, the authors point out.

High doses of ketamine are typically used as a general anesthetic, while lower doses are used for pain relief alone or in combination with opioids, said Dr. Francesca Beaudoin of the Alpert Medical School of Brown University in Providence, Rhode Island.

"There is interest in ketamine because it can work quickly, does not affect breathing or reduce blood pressure like opioids, and may reduce opioid use," Beaudoin, who wasn't involved in the study, said by email.

"Exposing less people to opioids over time may result in fewer people developing misuse or an opioid use disorder," Beaudoin said. "In addition, pain management is not a one size fits all approach, some medications work better in some people or some conditions - it is nice to have options when managing pain."

SOURCE: The Clinical Journal of Pain, online February 19, 2020.