Management of Postherpetic Neuralgia With Intrathecal Methylprednisolone

Abstract

Postherpetic neuralgia (PHN) is the most common complication of herpes zoster. Patients older than 60 years of age have a higher risk of PHN than do the younger patients. 1,2 There are many definitions of PHN in the literature in terms of timing (following rash healing, versus a defined time after onset of herpes zoster, 1 or 2 mo), duration (any time after zoster or a minimum of 6 mo after zoster), and type of pain (such as lancinating pain or allodynia). 3 PHN may include a wide array of presentations, from brief intermittent mild pain that resolves spontaneously to chronic recalcitrant, persistent, and severe pain unremitting to multiple therapies. A prospective study conducted on 457 patients with herpes zoster suggests that a physician can expect to see 4 cases of herpes zoster per year and 1 case of PHN lasting more than 3 months every 3 years. 4 Meta-analysis of 42 randomized controlled trials of acute zoster treatments have shown the incidence of pain at 3 months to be between 17 and 60%. 5 There is limited evidence that any of the conventional therapies for treating acute zoster have an impact on development of PHN. 5,6

A Meta-Analysis of Therapeutic Efficacy and Safety of Gabapentin in the Treatment of Postherpetic Neuralgia from Randomized Controlled Trials

“…At present, most of the clinical applications on neuropathic pain patients consisted of the antiviral treatment of early-onset herpes zoster. For patients with persistent pain, a combination of multiple medications is used, including opioid analgesics (morphine and oxycodone [ 4 ]), TCAs (amitriptyline [ 5 ] and doxepin hydrochloride), anticonvulsant [ 6 ] (gabapentin, pregabalin, and carbamazepine), topical drugs (piroxicam patch, lidocaine patch [ 7 ], and low concentrations of capsaicin patches), intrathecally given drugs (methylprednisolone [ 8 ]), and intravenous drugs (ketamine). All of these drugs have achieved good results to some extent, but their individual differences are large and cause many adverse reactions.…”

Enhancing the Relative Safety of Intentional or Unintentional Intrathecal Methylprednisolone Administration by Removing Polyethylene Glycol

“…[1][2][3][4] However, intrathecal MPA administration has been implicated in causing neurological complications, 5-10 which occurred mainly in patients who had repeated injections.…”

“…[5][6][7][8][9][10] Because there is no preservative-free, commercial formulation of MPA, we recently presented a case wherein we attempted to reduce the concentration of PEG in the MPA suspension by inverting the vial before sterilely aspirating the vial contents into a syringe for subsequent injection. 4 The purpose of this brief study was to precisely quantify the concentration of PEG in the MPA suspension.…”

“…[1][2][3][4] Contemporary thinking is to reserve this therapy for individuals who have failed to respond to conventional, noninterventional approaches to manage their pain. 1,2 There is also a possibility of unintentional intrathecal injection of methylprednisolone occurring during epidural steroid injections.…”