Table of Contents

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Amitriptyline

Outcome Relative Benefit/Risk
(95% CI)
Treatment Event Rate (%) Placebo Event Rate (%) NNT/NNH
Moderate pain improvement or better 2.0
(1.5, 2.8)
2.0(0.25) = 50% 25% 4
Adverse Event - Dry mouth * 5.66
(1.37, 23.39)
12/35 = 34.3% 2/33 = 6.1% 4
Adverse Event - Sleepiness 3.77
(1.17, 12.18)
12/35 = 34.3% 3/33 = 9.1% 4
Adverse Event - Loss of balance 6.60
(0.86, 50.79)
7/35 = 20% 1/33 = 3% NSS
Adverse Event - Stopped due to side effects 2.23
(1.11, 4.45)
25/159 = 15.7% 10/144 = 6.9% 12
Cost Amitriptyline 10 mg once daily: $1.50 to $2.00 (CAN)
Amitriptyline 25 mg once daily: $2.50 to $3.50 (CAN)
(Canadian medication cost for 30 days supply without pharmacy dispensing fees included)
* Confidence intervals were not provided in the article used for summary therefore we calculated the interval using MedCalc

Cannabinoids

Outcome Relative Benefit/Risk
(95% CI)
Treatment Event Rate (%) Placebo Event Rate (%) NNT/NNH
Greater than 30% improvement in pain 1.37
(1.14, 1.64)
1.37(0.25) = 34.3% 25% 11
Adverse Event - Sleepiness 1.66
(1.46, 1.89)
320/636 = 50% 224/737 = 30% 5
Adverse Event - "Feeling High" 10.6
(6.86, 16.50)
162/470 = 35% 17/562 = 3% 4
Adverse Event - Speech disorders 2.91
(1.28, 6.64)
42/132 = 32% 5/68 = 7% 5
Adverse Event - Dizziness 2.87
(2.02, 4.08)
116/363 = 32% 33/303 = 11% 5
Adverse Event - Stopped due to side effects Due to combination of studies, unable to obtain accurate value 90/849 + 108/1003 + 40/363 = 11% 38/725 + 18/1108 + 11/303 = 3% 14
Cost Nabilone 2 to 6 mg/day: $94 to $305 (CAN)
Nabiximols 4-12 sprays/day: $226 to $903 (CAN)
Medical marijuana 1-3 gm/day: $250 to $750 (CAN)
(Canadian medication cost for 30 days supply without pharmacy dispensing fees included)

Duloxetine

Outcome Relative Benefit/Risk
(95% CI)
Treatment Event Rate (%) Placebo Event Rate (%) NNT/NNH
Greater than 30% improvement in pain 1.53
(1.33, 1.75)
1.53(0.25) = 38.3% 25% 8
Adverse Event - Nausea 2.61
(2.14, 3.18)
424/1816 = 23.3% 156/1826 = 8.5% 7
Adverse Event - Dry mouth 2.63
(1.89, 3.67)
125/1036 = 12.1% 44/968 = 4.5% 14
Adverse Event - Sleepiness 2.94
(2.17, 3.97)
149/1335 = 11.2% 55/1343 = 4.1% 15
Adverse Event - Dizziness 1.84
(1.35, 2.51)
109/1131 = 9.6% 56/1126 = 5.0% 22
Adverse Event - Stopped due to side effects 1.95
(1.60, 2.37)
257/2372 = 10.8% 137/2465 = 5.6% 19
Cost Duloxetine 60 mg once daily: $29 to $32 (CAN)
(Canadian medication cost for 30 days supply without pharmacy dispensing fees included)

Gabapentin

Outcome Relative Benefit/Risk
(95% CI)
Treatment Event Rate (%) Placebo Event Rate (%) NNT/NNH
At least a moderate improvement in pain 1.73
(1.47, 2.03)
1.73(0.25) = 43.3% 25% 6
Adverse Event - Dizziness 2.87
(2.40, 3.44)
525/2755 = 19.1% 130/1984 = 6.6% 8
Adverse Event - Problems with balance 5.53
(2.49, 12.28)
39/279 = 14% 5/231 = 2.2% 9
Adverse Event - Sleepiness 2.82
(2.27, 3.50)
358/2531 = 14.1% 92/1757 = 5.2% 12
Adverse Event - Swelling (especially in ankles) 4.12
(2.66, 6.39)
132/2003 = 6.6% 20/1322 = 1.5% 20
Adverse Event - Stopped due to side effects 1.38
(1.14, 1.67)
291/2557 = 11.4% 144/1789 = 8.0% 31
Cost Gabapentin 300 mg once daily: $5.50 to $6.00 (CAN)
(Canadian medication cost for 30 days supply without pharmacy dispensing fees included)

High-Dose Opioids

Outcome Relative Benefit/Risk
(95% CI)
Treatment Event Rate (%) Placebo Event Rate (%) NNT/NNH
Benefit (at least 33% pain relief) 1.71
(1.33, 2.21)
1.71(0.25) = 42.8% 25% 6
Adverse Event - Constipation 3.89
(2.91, 5.20)
192/566 = 33.9% 48/548 = 8.8% 4
Adverse Event - Sleepiness 1.93
(1.07, 3.49)
110/376 = 29.3% 49/362 = 13.5% 7
Adverse Event - Nausea 2.95
(2.22, 3.94)
154/566 = 27.2% 51/548 = 9.3% 6
Adverse Event - Dizziness 2.60
(1.57, 4.32)
122/566 = 21.6% 45/548 = 8.2% 8
Adverse Event - Stopped due to side effects 2.92
(1.77, 4.83)
55/435 = 12.6% 18/432 = 4.2% 12
Cost Morphine 60 mg SR Once Daily: $14 - $30 (CAN)
(Canadian medication cost for 30 days supply without pharmacy dispensing fees included)

Pregabalin

Outcome Relative Benefit/Risk
(95% CI)
Treatment Event Rate (%) Placebo Event Rate (%) NNT/NNH
Greater than 30% improvement in pain 1.65
(1.34, 2.04)
1.65(0.25) = 41.3% 25% 7
Adverse Event - Dizziness 3.39
(2.82, 4.08)
422/1445 = 29.2% 126/1465 = 8.6% 5
Adverse Event - Sleepiness 3.96
(3.08, 5.09)
271/1445 = 18.8% 70/1465 = 4.8% 8
Adverse Event - Stopped due to side effects 1.92
(1.55, 2.37)
218/1445 = 15.1% 115/1465 = 7.8% 14
Cost Pregabalin 300 mg once daily: $17 to $52 (CAN)
(Canadian medication cost for 30 days supply without pharmacy dispensing fees included)

Other Neuropathic Pain Interventions

Below are potential treatment options that were not included in the comparison tool due to limited evidence for these agents. Systematic reviews including less than 200 patients and/or meta-analyses of nonspecific or unclear outcomes were excluded. This was done in order to reduce risk of bias and a potential overestimation of benefit.

Healthcare professionals may want to see the evidence for these agents and therefore, a summary of what was found in the literature for reference is provided along with some clinical limitations for the agents and typical dosing.

Intervention Primary Condition Outcome Possible Benefit Placebo Clinical Limitations
Capsaicin (Low Concentration) *
Applied topically 3x/day to area
Peripheral Neuropathy >50% pain relief ~29% ~13%
  • Can lead to significant burning/stinging of the skin
  • This tends to be reduced with repeated use
  • Do not use on damaged or broken skin and avoid sensitive areas
Tramadol
100 to 200 mg daily
Chronic Neuropathic Pain >30% pain relief over baseline ~57% ~19%
  • Can lead to drowsiness
  • May cause opioid dependence
Botox
50 to 200 IU to area every three months
Peripheral Neuropathy 30%, 50% or moderate pain relief (pooled) ~60% ~6%
  • Requires repeated injections
Carbamazepine
100 to 2400 mg daily
  • Trigeminal Neuralgia
  • Post-herpetic Neuralgia
  • Post-Stroke/Central
Any pain improvement ~61% ~9%
  • Can lead to drowsiness
  • Need to monitor CBC with differential and platelets prior to and during therapy
Venlafaxine *
75 to 150 mg daily
  • Diabetic Neuropathy
  • Atypical facial pain
Moderate pain relief or better ~47% ~22%
  • Can cause sleep disturbances and headaches
  • Can cause withdrawal effects if stopped abruptly

* The difference in efficacy between this treatment and placebo was not statistically different
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