Lidocaine Infusions Associated with Pain Relief for Patients with Refractory Chronic Migraine

Lidocaine infusions may be associated with short- and medium-term pain relief in refractory chronic migraine (rCM), according to a study recently published in Regional Anesthesia & Pain Medicine. These findings suggest that lidocaine may be a viable treatment for patients with rCM who have failed other treatments, according to the study investigators.

Generally, rCM has been defined as the failure of all available preventives and the presence of at least 8 debilitating headache days per month for at least 6 consecutive months, according to the study. Though continuous multiday lidocaine infusion has been suggested as a treatment in the population with rCM, existing studies on the treatment are limited.

Researchers conducted a study to assess the change in headache pain from baseline to hospital discharge after receiving a continuous lidocaine infusion and aggressive inpatient treatment for patients with rCM.

The study also assessed pain, change in number of headache days, and percentage of sustained responders 25 to 65 days after treatment. Adverse drug effects (ADEs), acute responder rates, and lidocaine plasma levels were also reviewed.

Researchers queried the electronic medical record (EMR; Epic) for patients with rCM hospitalized from April 1, 2017, through April 1, 2020, to the Jefferson Inpatient Headache Unit in Philadelphia for inpatient continuous infusion with lidocaine.

Of 832 records for hospital admissions involving continuous multiday lidocaine infusions for migraine, 602 admissions met the study criteria. Mean (SD) age of the patients was 46 (14) years, and the majority (81.1%) were female.

Patients included in this study were all in the most severe class of rCM as defined by previous research. These patients in class IV experienced “failure of adequate treatment trials of 3 drugs” and “failed aggressive infusion or inpatient treatment.” Patients who received multiday continuous lidocaine infusion as part of their aggressive inpatient treatment were found to have significant improvement in pain immediately following infusion.

The results showed a decrease in median pain rating from baseline of 7.0 (5.0-8.0) to 1.0 (0.0-3.0) at the end of hospitalization (p < 0.001).

Of the total patients, 87.8% were considered acute responders. At 1 month, 43.2% of those patients were sustained responders. No difference was found in total lidocaine dose administered to sustained responders versus those who were not sustained responders.

The high acute responder rate indicated that the combination of lidocaine with other aggressive intravenous therapies was associated with rapid relief; however, the effect was found to wane over time.

Average pain remained below the baseline at office visit 1 (5.5 (4.0-7.0); p < 0.001). Headache days decreased from a mean (SD) of 2.8 (3.9) at baseline to 22.5 (8.3) at the post-discharge office visit (p < 0.001).

All ADEs were mild, occurring in a minority of patients, with nausea and vomiting being the most common ADEs in this study. Overall, the treatment was found to be well-tolerated.

These findings indicate that lidocaine may be a viable treatment for patients with rCM who have failed other treatments, according to the investigators.

To further confirm the results of their study, the researchers recommend a prospective, randomized, double-blind trial, though they acknowledge the difficulty of conducting such a study due to the nature of rCM.

Despite the need for additional research, the authors of the study hope their findings can support the use of lidocaine infusions in a challenging population for rCM, informing likelihood for relief and expected duration of relief.

The lack of clinical trials including patients with rCM has led to inadequate insurance coverage for aggressive therapies such as lidocaine, according to the authors. They encourage funding agencies to perform prospective studies in patients with rCM to generate evidence to support aggressive therapies.

The authors noted that the study faced some limitations. Patients with multiple admissions during the study period were included in the study; however, each admission was treated as a separate set of data points due to differences in degree of pain and disability with each admission, and admissions were spaced apart by approximately 6 months or more.

Reference

Schwenk ES, Walter A, Torjman MC, Mukhtar S, Patel HT, Nardone B, et al. Lidocaine infusions for refractory chronic migraine: a retrospective analysis. Reg Anesth Pain Med. 2022;47:408–413. https://rapm.bmj.com/content/47/7/408. Published May 24, 2022. Accessed July 8, 2022.