Efficacy of paravertebral block versus local lidocaine/capsaicin in the treatment of postherpetic neuralgia

Abstract

Background Postherpetic neuralgia (PHN) is an extreme form of neuropathic pain. Although a number of treatment options are available, drug interactions and side effects frequently limit their use. This study aimed to compare the efficacy of repeated paravertebral block with that of topical sequential lidocaine/capsaicin therapy, considering the degree of patient comfort, in the management of pain of PHN after resolution of the acute phase. Patients and methods We compared the efficacy of repeated paravertebral block with that of topical sequential lidocaine/capsaicin therapy, considering the degree of patient comfort, in the management of pain of PHN after resolution of the acute phase in 80 patients divided into two equal groups. The patients in group I received topical lidocaine 2% cream, followed after 20 min by capsaicin 7% ointment. The patients in group II received twice-weekly paravertebral injections of the affected dermatomes with a mixture of bupivacaine 0.25%+dexamethasone. Patients were followed up for pain (using visual analogue score), allodynia (using numeric rating scale), Q+-uality of life [using The European quality-of-life questionnaire (EQ-5D) and sleep questionnaire (sleep Q)], and finally their satisfaction (on a three-category score). Results It was found that after 1 week of therapy, reduction in the severity of pain and allodynia was significantly more remarkable in group 1 compared with group 2. After 2 weeks of therapy, there was a significantly greater improvement in pain and allodynia, associated with a greater improvement in quality of life in group I compared with group II. By the end of the study period, the topical regimen was shown to be significantly more pleasant for most of the patients. Conclusion The use of topical lidocaine/capsaicin sequentially leads to better improvement of pain and allodynia, with more improvement in sleep pattern and hence of quality of life than repetitive paravertebral block with bupivacaine/dexamethasone when either of them is combined with gabapentin/amitriptyline oral therapy.