From the Guidelines
Lower limb neuropathic pain is characteristically different from other pain causes due to its distinctive qualities and patterns, typically presenting as burning, electric shock-like, or shooting sensations, often accompanied by pins and needles, tingling, or numbness in the affected limb, and is best managed with medications such as pregabalin or duloxetine, as recommended by the most recent guidelines 1.
Characteristics of Lower Limb Neuropathic Pain
- Neuropathic pain commonly occurs spontaneously without obvious stimuli
- Follows nerve distribution patterns rather than dermatomes
- May be associated with allodynia (pain from normally non-painful stimuli) and hyperalgesia (increased pain sensitivity)
- Patients often describe the pain as worse at night
- May report sensory abnormalities like decreased sensation or hypersensitivity in the affected area
Treatment of Lower Limb Neuropathic Pain
- The pain typically doesn't respond well to conventional analgesics like NSAIDs or acetaminophen
- Requires specific medications such as gabapentinoids (gabapentin 300-3600mg daily or pregabalin 150-600mg daily)
- Tricyclic antidepressants (amitriptyline 10-75mg at bedtime) or serotonin-norepinephrine reuptake inhibitors (duloxetine 30-120mg daily) may also be effective
- Pregabalin and duloxetine have received regulatory approval for the treatment of neuropathic pain in diabetes 1
Key Considerations
- Neuropathic pain can be severe and can impact quality of life, limit mobility, and contribute to depression and social dysfunction 1
- No compelling evidence exists in support of glycemic control or lifestyle management therapies for neuropathic pain in diabetes or prediabetes, which leaves only pharmaceutical interventions 1
From the FDA Drug Label
The efficacy of pregabalin for the management of neuropathic pain associated with spinal cord injury was established in two double-blind, placebo-controlled, multicenter studies Patients were enrolled with neuropathic pain associated with spinal cord injury that persisted continuously for at least three months or with relapses and remissions for at least six months. The patients had a minimum mean baseline pain score of greater than or equal to 4 on an 11-point numerical pain rating scale ranging from 0 (no pain) to 10 (worst possible pain).
The characteristic of lower limb neuropathic pain vs other causes is not explicitly stated in the provided drug label. However, it can be inferred that neuropathic pain associated with spinal cord injury is characterized by:
- Persistence of pain for at least three months or relapses and remissions for at least six months
- A minimum mean baseline pain score of greater than or equal to 4 on an 11-point numerical pain rating scale 2
From the Research
Characteristics of Lower Limb Neuropathic Pain
- Neuropathic pain is a special type of pain condition with a distinct pathophysiological basis and treatment compared to nociceptive pain 3
- It arises as a consequence of a lesion or disease affecting the somatosensory system, and is generally chronic and challenging to treat 4
- Patients with neuropathic pain may present with positive and negative sensory and motor signs and symptoms, as well as a variety of comorbid conditions 5
- Clinical evaluation, rather than diagnostic tests, is one of the best available tools for assessment and diagnosis of neuropathic pain 5
Diagnosis and Assessment
- A thorough history, including medical, functional, and psychosocial evaluations, is key to a thorough assessment of neuropathic pain 5
- The physical and neurologic examination remains a critical element for patient evaluation, including an assessment of spontaneous pain, pain evoked by daily activities, and other abnormal sensations 5
- Sensitivity to pinprick, touch, pressure, cold, heat, and vibration are measured, often confirming the suspected diagnosis 5
Treatment
- First-line treatments for neuropathic pain include tricyclic antidepressants (such as amitriptyline), serotonin-norepinephrine reuptake inhibitors (such as duloxetine), pregabalin, and gabapentin 6, 3, 7
- Second-line treatments include lidocaine plasters and capsaicin high concentration patches for peripheral neuropathic pain only, and tramadol 6, 7
- Third-line treatments include strong opioids and botulinum toxin A (for peripheral neuropathic pain) 7