NOVEMBER 22, 2024
In an effort to combat the risk for opioid misuse, intravenous lidocaine is increasingly used as an intraoperative analgesic and to treat chronic pain. However, physicians’ understanding of exactly how lidocaine affects the brain is lacking.
Now, new data published in the British Journal of Anesthesia (published online October 21, 2024. www.bjanaesthesia.org/article/S0007-0912(24)00548-8/fulltext) indicate that IV lidocaine helps relieve pain through two mechanisms of
In an effort to combat the risk for opioid misuse, intravenous lidocaine is increasingly used as an intraoperative analgesic and to treat chronic pain. However, physicians’ understanding of exactly how lidocaine affects the brain is lacking.
Now, new data published in the British Journal of Anesthesia (published online October 21, 2024. www.bjanaesthesia.org/article/S0007-0912(24)00548-8/fulltext) indicate that IV lidocaine helps relieve pain through two mechanisms of action.
“Lidocaine was associated with broad reductions in functional MRI (fMRI) response to acute pain and modulated whole-brain functional connectivity, predominantly decreasing long-range connectivity,” the study’s authors explained.
The researchers enrolled 27 healthy adults (age, 22-55 years) in the open-label study. At baseline, all patients underwent an fMRI and a pain response task in which an electrical nerve stimulator (connected to a patient’s index finger) was titrated up in intensity until the patient reported a score of 7 out of 10 on a pain scale. Motor response and combined recognition time scores were also assessed. After administration of lidocaine (mean dose, 1.8 mg kg−1), the fMRI, motor response and combined recognition assessment were repeated.
Compared with the baseline recording, lidocaine infusion was associated with a significant decrease in pain-evoked responses in the insula (left: Z=3.6; right: Z=3.6) and other brain areas commonly involved in acute pain processing, including the cingulate gyrus, thalamus and primary sensory cortex. Lidocaine administration was also associated with significant diffuse reductions in both region-to-region and global brain connectivity measures. Additionally, after lidocaine administration, there were “small but significant decreases in pain perception and memory performance,” according to the study authors.
The researchers concluded that “this study lays the foundation for a better understanding of systems-level neuroscience changes that occur with lidocaine and work towards refining the clinical use of this important analgesic agent.”
—Myles Starr
