Intravenous Lidocaine for pain in the ED: what the evidence shows?

Author: Lucas Oliveira J. e Silva (@lucasojesilva12)

Lidocaine is a local anesthetic agent of the amide type that has been described as containing analgesic (1), anti-hyperalgesic (2) and anti-inflammatory properties (3,4). It has a short half-life (60 to 120 minutes) and its side effects are often predictable. Due to its short half-life, toxicity symptoms at lower doses are generally transient, although its analgesic effect might last more than expected (5). Lidocaine for pain control, administered by intravenous (IV) injection, has been studied in various settings, including the operating room for management of perioperative pain (5) and outpatient clinics for treatment of neuropathic pain. Its use in the Emergency Department (ED), however, has only recently gained attention after emerging evidence for the management of pain of renal colic patients in the ED (6,7).

The current public health crisis of opioid addiction driven by increased prescribing of these medications, and increased number of overdose-related deaths, further emphasizes the need for alternative approaches for pain control.

In order to better understand the whole body of evidence, we conducted a systematic review to evaluate the safety and efficacy of IV lidocaine for adult patients undergoing pain management in the ED through the outcomes of reduction in pain scores, need for rescue analgesia, and incidence of adverse drug reactions.

Here the link to the paper (Annals of EM):

We found 1947 titles and abstracts and 61 potentially relevant studies were identified. After full-text review, a total of 8 studies met our inclusion criteria. Standard guidelines for systematic reviews were followed (PRISMA and GRADE). Qualitative analysis was done for all studies, and a meta-analysis was not possible given the low quality and significant clinical heterogeneity across the studies.

We found that the value of intravenous lidocaine as an analgesic modality and option for pain relief in the ED is promising, but yet to be determined. Four of six randomized controlled trials found comparable or superior reduction in pain scores using IV lidocaine when compared to active controls (ie: morphine). Lidocaine appeared to be effective in patients with renal colic and critical limb ischemia, and did not appear to be beneficial for migraine headaches.

The evidence for safety of IV lidocaine in the ED is also limited, with only 6 studies reporting the adverse drug reactions. One case-series reported a cardiac arrest secondary to the use of the wrong dose of IV lidocaine in the ED.

Main findings (Table 2 of the paper):

In summary, this systematic review found limited evidence to support the efficacy and safety of IV lidocaine as a single agent and/or as an adjunct to other parenteral analgesics for short-term pain relief in the ED. Intravenous lidocaine may be effective for conditions like visceral, neuropathic and ischemic pain. Further well-designed studies are needed to address the role of IV lidocaine for different causes of pain in the ED, the most appropriate dose and timing for administration, and confirm its safety in different age groups and clinical populations.

Bottom-line: Although promising, the current body of evidence is limited and intravenous lidocaine for pain management needs further well-designed studies to determine its safety and efficacy before the routine use for analgesia in the ED.

Link to article

REFERENCES

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