Repeated Intravenous Lidocaine Infusions for Patients with Fibromyalgia: Higher Doses of Lidocaine Have a Stronger and Longer-Lasting Effect on Pain Reduction

Patient Expectations and Therapeutic Alliance Affect Pain Reduction Following Lidocaine Infusion in an Interdisciplinary Chronic Pain Clinic

Pain experience is affected by both ascending nociceptive signals and descending modulation. Expectations can affect pain experience and augment treatment-induced analgesia through descending inhibitory modulation of pain. This open-label, prospective cohort study examined the association between participant expectation ratings and pain reduction in adult participants with chronic pain receiving an intravenous lidocaine infusion. We aimed to explore whether: 1) participants' expectations of treatment efficacy were associated with pain reduction over 8 weeks after infusion; and 2) participants' therapeutic alliance was associated with expectations and/or pain reduction. We recruited 70 participants with chronic pain scheduled for lidocaine infusion. Study measures included pain intensity (pre-treatment, post-treatment, and daily for 8 weeks), treatment expectations (EXPECT), and therapeutic alliance (Trust in Physician and Working Alliance Inventory-Short Revised). Baseline treatment expectations were significantly correlated with pain reduction (r = .42, P < .01). Therapeutic alliance was significantly correlated with expectations (r = .27, P < .05) and pain reduction (r = .38, P < .01). This study quantifies the contribution of: 1) treatment expectations; and 2) therapeutic alliance to the magnitude of lidocaine-induced pain reduction. Results generate the hypothesis that focused efforts to augment treatment expectations and therapeutic alliance could serve to improve pain treatment outcomes. PERSPECTIVE: This study evaluates the relationship between pain reduction and ratings of: 1) treatment expectations; and 2) therapeutic alliance following an intravenous lidocaine infusion. Results generate the hypothesis that focused efforts to augment treatment expectations and therapeutic alliance could serve to improve pain treatment outcomes.

Integrating mechanistic-based and classification-based concepts into perioperative pain management: an educational guide for acute pain physicians

Chronic pain begins with acute pain. Physicians tend to classify pain by duration (acute vs chronic) and mechanism (nociceptive, neuropathic and nociplastic). Although this taxonomy may facilitate diagnosis and documentation, such categories are to some degree arbitrary constructs, with significant overlap in terms of mechanisms and treatments. In clinical practice, there are myriad different definitions for chronic pain and a substantial portion of chronic pain involves mixed phenotypes. Classification of pain based on acuity and mechanisms informs management at all levels and constitutes a critical part of guidelines and treatment for chronic pain care. Yet specialty care is often siloed, with advances in understanding lagging years behind in some areas in which these developments should be at the forefront of clinical practice. For example, in perioperative pain management, enhanced recovery protocols are not standardized and tend to drive treatment without consideration of mechanisms, which in many cases may be incongruent with personalized medicine and mechanism-based treatment. In this educational document, we discuss mechanisms and classification of pain as it pertains to commonly performed surgical procedures. Our goal is to provide a clinical reference for the acute pain physician to facilitate pain management decision-making (both diagnosis and therapy) in the perioperative period.

Efficacy of Acupuncture, Intravenous Lidocaine, and Diet in the Management of Patients with Fibromyalgia: A Systematic Review and Network Meta-Analysis

Introduction: This network meta-analysis aimed to assess the efficacy of acupuncture, intravenous lidocaine, and diet compared with other comparators such as physiotherapy and sham/placebo in fibromyalgia patients. Materials and Methods: We searched Embase, PubMed, Scopus, and Web of Science for relevant studies till September 2021. The included studies were randomized controlled clinical trials. For the network meta-analysis, we used the R software. Results: There were 23 included RCTs. The total sample size was 1409 patients. Compared with the sham/placebo group, the network analysis showed the highest improvement in the quality of life in the acupuncture group standardized mean difference (SMD) = −10.28, 95%-CI [−14.96; −5.59]), and then in the physiotherapy group (SMD = −7.48, 95%-CI [−14.72; −0.23]). For the pain, there was a significant reduction with acupuncture (SMD = −1.69, 95%-CI [−2.48; −0.89]), compared with sham/placebo. Regarding depression, it showed a significant reduction with acupuncture (SMD = −9.64, 95%-CI [−16.13; −3.14]) compared with sham/placebo. Finally, for stiffness, it showed no significant differences in the stiffness between acupuncture (SMD = −8.52, 95%-CI [−20.40; 3.36]), fluoxetine (SMD = −6.52, 95%-CI [−29.65; 16.61]), and physiotherapy (SMD = −4.64, 95%-CI [−22.83; 13.54]) compared with sham/placebo. Conclusions: The acupuncture showed a significant effect in the management of fibromyalgia patients. It reduced pain, depression, and enhanced the quality of life. While physiotherapy showed a significant improvement in the quality of life only. In contrast, intravenous lidocaine and diet showed no significant differences when compared with sham/placebo.

Lidocaine in fibromyalgia: A systematic review

BACKGROUND

Fibromyalgia (FM) patients are treated with antidepressants, and in most cases, these drugs lose efficacy or present side effects. Intravenous lidocaine (IL) is an anesthetic drug used in some FM trials.

AIM

To systematically review the safety and efficacy of IL in FM patients.

METHODS

To systematically search PubMed for articles in English, Spanish, and Japanese with English Abstracts on FM and lidocaine between 1966 and February 2021. This study was registered at PROSPERO.

RESULTS

We found only ten articles published in this field, with a total of 461 patients. Females predominated varying from 95% to 100% in the studies. Age varied from 40.9 to 55 years old. Disease duration varied from 1 mo to 6.4 years. Lidocaine dose varied from 2 to 7.5 mg/kg via intravenous infusion. Follow-up period varied from 65.7 to 90 days. Regarding outcomes, most studies used the visual analogue scale (VAS) for pain; before short-term lidocaine administration, VAS was between 6.1 and 8.1 and after treatment was between 1.7 and 4.5 mm. Concerning long term lidocaine, VAS varied from 30% to 35.4% after lidocaine infusion. Side effects were observed in 0% to 39.6% of cases, they were usually mild or moderate.

CONCLUSION

This study demonstrates the short-term effectiveness and safety of intravenous lidocaine in FM patients. However, more studies, including long-term follow-up, are still needed.

Lidocaine infusions in chronic pain management: A prospective case series analysis

Chronic pain conditions are prevalent and cause a significant burden of disease. Intravenous lidocaine infusions have been reported to have an analgesic effect in patients with chronic neuropathic pain, but there is limited data supporting the efficacy of lidocaine across other chronic pain phenotypes. Our study aimed to evaluate the efficacy of a single infusion of intravenous lidocaine for pain relief and the impact on quality of life. We evaluated data from 74 patients with chronic pain who were treated with intravenous lidocaine at a specialist pain centre. Participants completed a questionnaire consisting of the Brief Pain Inventory (BPI) Short Form and additional EQ-5D quality of life metrics, before treatment and at follow-up.

Data comparing pain severity did not demonstrate a statistically significant change after treatment when averaged across the entire patient cohort (6.15–5.88, p = .106), irrespective of gender or pain phenotype. Scores for pain interference showed statistically significant reductions following treatment (7.05–6.41, p = .023), which may have been driven through improvements in sleep (7.41–6.35, p = .001); however, these reductions are not clinically significant.

The patient cohort was stratified into responders and non-responders based on >30% improvement in response to an overall impression of pain reduction question following treatment. In the ‘responder’ cohort, pain intensity scores showed a statistically significant reduction post-infusion (6.18–5.49, p = .0135), but no change was apparent for non-responders (6.07–6.09, p = .920). There were no differences between responders and non-responders for pain sub-types in our study.

This study found no difference in pain outcomes in a cohort of patients with chronic pain, a mean of 63 days following a single lidocaine infusion. However, a specific subgroup of responders may show slight improvements in some pain outcomes that may warrant further exploration.

Antimalarial primaquine for spinal sensory and motor blockade in rats

OBJECTIVES

The purpose of the experiment was to estimate whether intrathecal antimalarial drugs could provoke spinal block, and their comparison with lidocaine.

METHODS

Rats were intrathecally administrated with antimalarial agents (primaquine, chloroquine, hydroxychloroquine and amodiaquine) and lidocaine, and neurobehavioural examinations (nociception, proprioception and motor function) were assessed; n = 8 per group. One-way and two-way analysis of variance were designed to analyse data.

KEY FINDINGS

At a concentration of 20 mM, primaquine (0.46 mg/rat) exhibited the longest duration and the most potent effect of nociceptive, proprioceptive and motor blockade (P < 0.01) among five drugs, whereas the other antimalarial drugs displayed a lesser or similar potency of spinal blockade compared with lidocaine (0.29 mg/rat). In dose-dependent studies, primaquine was more potent (P < 0.01) than lidocaine for spinal block. At ED25, ED50 and ED75 equipotent doses, primaquine produced a greater duration of spinal motor, proprioceptive and nociceptive blockade when compared with lidocaine (P < 0.01).

CONCLUSIONS

Primaquine, chloroquine, hydroxychloroquine and amodiaquine produced spinal blockade. Primaquine was more potent and displayed a prolonged life of local anaesthetic effect compared with lidocaine, whereas the other antimalarial drugs displayed a lesser or similar potency compared with lidocaine.

Fibromyalgia in Older Individuals

Fibromyalgia (FM) is a condition of chronic widespread pain (CWP) that can occur throughout the life cycle and is likely underrecognized in older patients. FM is associated with considerable suffering and reduction in quality of life and may occur as a unique condition, but in older patients is most likely to be associated with another medical illness. Understood mechanistically to be a sensitization of the nervous system, recently identified as nociplastic pain, FM is accepted as a valid medical illness that requires a positive diagnosis and directed treatments. The cornerstone of treatments for FM are nonpharmacologic interventions, with the understanding that medications provide only modest benefit for most patients, and with particular concern about adverse effects in older patients. If FM is not recognized, treatments may be misdirected to the other medical condition, with failure to address FM symptoms, leading to overall poor outcome. In contrast, new complaints in older patients should not immediately be attributed to FM, and physicians should be vigilant to ensure that onset of a new illness is not ignored. As FM is most often a lifelong condition, patients should be encouraged to identify their own personal strategies that can attenuate symptoms, especially when symptoms flare. Continued life participation should be the outcome goal.

Utilization of Magnesium for the Treatment of Chronic Pain

Context

The International Association for the Study of Pain (IASP) defines chronic pain as pain that persists or recurs for longer than 3 months. Chronic pain has a significant global disease burden with profound effects on health, quality of life, and socioeconomic costs.

Evidence Acquisition

Narrative review.

Results

There are several treatment options, including pharmacological therapy, physical rehabilitation, psychological therapies, and surgical interventions, for chronic pain management. Magnesium has been FDA-approved for several indications including hypomagnesemia, arrhythmia, prevention of seizures in eclampsia/preeclampsia, and constipation. Magnesium has been used for numerous off-label uses, notably for acute and chronic pain management. The mechanism of magnesium in pain management is primarily through its action as a voltage-gated antagonist of NMDA receptors, which are involved in pain transduction.

Conclusions

This narrative review will focus on the current evidence and data surrounding the utilization of magnesium as a treatment option for chronic pain.

Utilization of Intravenous Lidocaine Infusion for the Treatment of Refractory Chronic Pain

Context

Chronic pain accounts for one of the most common reasons patients seek medical care. The financial burden of chronic pain on health care is seen by direct financial cost and resource utilization. Many risk factors may contribute to chronic pain, but there is no definite risk. Managing chronic pain is a balance between maximally alleviating symptoms by utilizing a therapeutic regimen that is safe for long-term use. Currently, non-opioid analgesics, NSAIDs, and opioids are some of the medical treatment options, but these have numerous adverse effects and may not be the best option for long-term use. However, Lidocaine can achieve both central and peripheral analgesic effects with relatively few side effects, which may be an ideal compound for managing chronic pain.

Evidence Acquisition

This is a Narrative Review.

Results

Infusion of lidocaine (2-(diethylamino)-N-(2,6-dimethylphenyl)acetamide), an amino-amide compound, is emerging as a promising option to fill the therapeutic void for treatment of chronic pain. Numerous studies have outlined dosing protocols for lidocaine infusion for the management of perioperative pain, outlined below. While there are slight variations in these different protocols, they all center around a similar dosing regimen to administer a bolus to reach a rapid steady state, followed by infusion for up to 72 hours to maintain the therapeutic analgesic effects.

Conclusions

Lidocaine may be a promising pharmacologic solution with a low side effect profile that provides central and peripheral analgesia. Even though the multifaceted mechanism is not entirely understood yet, lidocaine may be a promising novel remedy in treating chronic pain in various conditions.