Study Finds Insufficient Evidence to Support Lidocaine Infusion for Chronic Neuropathic Pain

Authors of a systematic review published in The Clinical Journal of Pain found insufficient evidence to support lidocaine infusion for the treatment of chronic neuropathic pain in adult patients.

Investigators from Albany Medical College searched publication databases for studies of lidocaine infusion in the setting of neuropathic pain published between 1970 and 2021. A total of 27 studies comprising 358 patients were included.

In the setting of spinal cord injury, one study reported a significant pain reduction of 36% (P <.01) with both at-level (P <.01) and below-level (P =.018) effects 1 week after treatment with two 5-mg/kg lidocaine infusions. However, another study reported no significant pain-reduction effect from a 5-mg/kg lidocaine infusion, although the investigators did report a significant reduction in mechanical and cold allodynia compared with placebo (P =.0397).

In studies that evaluated multiple lidocaine doses, one study reported that both a 2-mg/kg dose and a 5-mg/kg dose significantly reduced pain scores (both P ≤.046); however, neither elicited an effect lasting more than 2 hours postinfusion. A study that evaluated 3 lidocaine dosages (5, 3, and 1 mg/kg/h) reported a significant effect lasting 6 hours for the highest lidocaine dosage (P =.01) and no effects for the lower dosages. A study that maintained plasma lidocaine concentrations at 0.5, 1.0, 1.5, 2.0, and 2.5 mcg/mL for 10 minutes during multiple treatment sessions revealed that doses eliciting plasma concentrations of at least 1.5 mcg/mL were associated with significant reductions in pain scores (P <.01); however, these effects did not persist to day 7.

For diabetic neuropathy, one study reported a significant reduction in pain scores following a 5-mg/kg lidocaine infusion, and another study reported greater effects of the same dose infusion among patients with an irritable nociceptor phenotype compared with those with a nonirritable nociceptor phenotype. In another study, significant effects from a 5-mg/kg (P <.05) and a 7.5-mg/kg (P <.01) lidocaine infusion were reported up to 28 days following treatment. Conversely, another study reported that no effects from a 5-mg/kg lidocaine infusion persisted longer than 10 days after infusion.

In postherpetic neuralgia, significantly reduced pain ratings were reported following a 5-mg/kg lidocaine infusion compared with saline (P =.02). In a study in which patients received both a 1-mg/kg and a 5-mg/kg lidocaine infusion as well as a saline infusion, pain scores were significantly reduced after all treatments, including the placebo. In a study that tracked the effect of lidocaine on pain over time, the peak reduction in pain from a 5-mg/kg infusion occurred at 1 to 2 hours following treatment and lasted up to 6 hours.

Study authors conclude, “Lidocaine infusion is not the current standard of care for chronic neuropathic pain management due to lack of adequate literature regarding its efficacy. The current evidence is limited and heterogenous [sic] with wide variation and inconsistent outcome reporting. No recommendation can be made based on the current literature.”

Disclosure: One study author declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.