Background: Postherpetic neuralgia (PHN) is one kind of severe neuropathic pain which currently cannot be effectively cured. Recent researches suggest that intravenous infusion of lidocaine has a therapeutic effect on neuropathic pain such as PHN; however, the optimal dose and frequency of lidocaine infusion and the effectiveness and safety of this treatment in PHN patients still needs more clinical research. The aim of this study was to evaluate the therapeutic effects of daily intravenous lidocaine infusion on the outcome of the routine treatment of PHN.
Methods: Sixty PHN patients were randomly divided into two groups: 1) control group (Control), treated with conventional therapies, such as antiepileptic pills, analgesics, neurotrophic medicines, paravertebral spinal nerve block and physiotherapy; 2) lidocaine group (Lido) received daily infusion of lidocaine (4 mg/kg) besides the conventional treatments. If the pain is not controlled sufficiently, additional tramadol is given and the average consumption of tramadol is calculated. Pain intensity was assessed before and after each infusion, and the number of breakthrough pain in the last 24 hrs were recorded. The incidence of adverse reactions related to intravenous lidocaine infusion was recorded.
Results: For five consecutive days, numeric rating scale (NRS) scores were significantly decreased after 1 hr of intravenous infusion of lidocaine. Compared with Control, the NRS scores and the frequency of breakthrough pain in the Lido were significantly reduced. In addition, the extra tramadol consumption in the Lido was significantly lower than that in the Control, and the average hospital stay of patients in Lido was decreased. However, anxiety and depression scores showed no difference between Lido and Control.
Conclusion: Daily intravenous lidocaine (4 mg/kg for 5 days) enhanced the outcome of PHN treatment, reduced the amount of analgesic medicine and shortened the length of hospital stay with no obvious adverse side effects.
This is most interesting and useful. Neuralgic pain is frustrating for patients and physicians. Treatment methods are poor, at best, with frequent complications. This could prove very helpful to many patients.
Only very short term outcomes were assessed, and masking was not clear. Lidocaine infusion occurred in the OR, saline infusion seems to not have benn similarly monitored. The authors didn't comment on the impressive improvement with saline and conservative Rx. The lidocaine group did a bit better, but given the toxicity of this antiarrhythmic, the study design issues and short term f/u, treatment is not ready for emulation.
This is directly and highly relevant in the subgroup of pain patients I see in primary care; however, I do not think this paper is relevant in general for primary care.
This is a very small study for patients that were hospitalized for a problem not requiring hospitalization.
The only limitation is the short-term effects of lidocaine Infusion were evaluated (also stated by the authors).
This is an RCT on a very important topic with important clinical implications. The study sheds some light on the short-term benefits and some of the potential side effects of an intravenous infusion of lidocaine in the treatment of PHN. However, the study, because of its design, is unable to answer key and new clinical questions such as the efficacy, dose and frequency of the infusion of lidocaine.