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302 Neuropathy – phantom limb pain
200 IU) is a treatment of choice for acute PLP flares. 1,12 As with other agents
with which ED providers may not be familiar, quick reference for safety
purposes (e.g. withholding of calcitonin in hypocalcemic patients) is necessary.
For patients with hypersensitivity to fish (in whom the nasal salmon
preparation is contraindicated), a human calcitonin preparation may be used.
The benzodiazepines, which potentiate the spinal neuronal inhibitory
effects of gamma-aminobutyric acid (GABA), may ameliorate pain from
acute PLP flares. Case reports suggest that both clonazepam and midazolam
are effective. 13,14 The familiarity of ED providers with safe use of midazolam
makes this an attractive choice. Slow infusion of up to 3–5 mg(over
10–20 min, with meticulous ventilatory monitoring), is supported by the
available case series data. 14,15
Midazolam is not the only procedural sedation drug with potential utility
for PLP. Multiple case series reports support ketamine use for acute PLP
flares. 16,17
In contradistinction to their utility in other forms of neuropathic pain,
antidepressants have only a limited role for acute PLP; they may be useful
as an aid to chronic management. 1 The exception may be the heterocyclic
antidepressant mirtazapine, for which there is open-label case series evidence
suggesting reduction in PLP via central mechanisms. 18
The anticonvulsants have been investigated for PLP, with mixed results.
Carbamazepine is postulated to be of utility, but supporting evidence for its
use in PLP is anecdotal. 19 There is stronger evidence for gabapentin prescription
in PLP. Case series evidence suggests utility for gabapentin, and a
clinical trial calculated that about one in four patients will achieve significant
pain relief with gabapentin. 20,21 Another RCT suggested limited gabapentin
efficacy. In this RCT, although over half of participants had a meaningful pain
decrease during the gabapentin phase (compared with 20% in the placebo
phase), no predefined efficacy endpoints were met. 22
Theoraldosingofgabapentin for NP follows an advancing regimen: 300 mg
HS on day one, followed by 300 mg BID on day two, then 300 mg TID on day
three. The drug can then be titrated up to 1800 mg/day over two weeks.
Another anticonvulsant, topiramate, is found useful in individual
time-series analyses. Three out of four amputee participants receiving