Table 2.

Selected neuropathic analgesic dosing regimens

AGENTINITIAL DOSETITRATIONDOSE RANGEADVERSE EFFECTSADDITIONAL INFORMATION
Anticonvulsants
  • Gabapentin100–300 mg/dIncrease by 100–300 mg/d every wk300–1200 mg 3 times/dDrowsiness, dizziness, peripheral edema, visual blurringDosage adjustments required in renal failure and in elderly patients
  • Pregabalin25–150 mg/dIncrease by 25–150 mg/d every wk150–300 mg twice dailyDrowsiness, dizziness, peripheral edema, visual blurringSimilar adjustments in renal failure
  • Carbamazepine100 mg/dIncrease by 100–200 mg/d every wk200–400 mg 3 times/dDrowsiness, dizziness, blurred vision, ataxia, headache, nausea, rashDrug of first choice for idiopathic trigeminal neuralgia; as an enzyme inducer, it might interfere with activity of other drugs such as warfarin; monitoring of blood counts and liver function recommended
TCAs
  • Amitriptyline, nortriptyline, or desipramine10–25 mg/dIncrease by 10 mg/d every wk10–100 mg/dDrowsiness, confusion, orthostatic hypotension, dry mouth, constipation, urinary retention, weight gain, arrhythmiaAmitriptyline more likely to produce drowsiness and anticholinergic side effects; contraindicated in patients with glaucoma, symptomatic prostatism, and substantial cardiovascular disease
SNRIs
  • Venlafaxine37.5 mg/dIncrease by 37.5 mg/d every wk150–225 mg/dNausea, dizziness, drowsiness, hyperhidrosis, hypertensionDosage adjustments required in renal failure
  • Duloxetine30 mg/dIncrease by 30 mg/d every wk60–120 mg/dSedation, nausea, constipation, ataxia, dry mouthContraindicated in patients with glaucoma
Controlled-release opioids*
  • Morphine15 mg every 12 hNANANausea, vomiting, sedation, dizziness, urinary retention, constipationConstipation requires concurrent bowel regimen; monitor for overdose, effectiveness, tolerance, dependence, and appropriateness
  • Oxycodone10 mg every 12 hNANA
  • Fentanyl12 µg/h (patch)NANA
  • Hydromorphone3 mg every 12 hNANA
Others
  • Tramadol50 mg/dIncrease by 50 mg/d every wk50–100 mg 4 times/d or 100–400 mg/d (controlled release)Ataxia, sedation, constipation, seizures, orthostatic hypertensionMight lower seizure threshold; use with caution in patients with epilepsy
  • Tapentadol (controlled release)50 mg every 12 hIncrease by 50 mg/dose every wkMaximum dose 500 mg in 24 hNausea, constipation, somnolence, dizziness, vomiting, fatigueContraindicated in patients with creatinine clearance < 0.5 mL/s/m2 and Child-Pugh class C. Caution in those at risk of seizure
  • LidocaineNANA5% patches or gel applied to painful areas for 12 h in a 24-h periodNAMost useful for postherpetic neuralgia; has virtually no systemic side effects; lidocaine patches not available in Canada
  • THC or nabiximols1–2 sprays every 4 h, maximum 4 sprays on day 1NA2 sprays 4 times/dDizziness, fatigue, nausea, euphoriaApproved in Canada for neuropathic pain associated with multiple sclerosis; causes positive urine drug test results for cannabinoids; monitor application site (oral mucosa)
  • Nabilone0.25–0.5 mg at night (owing to side effects of drowsiness and fatigue)Increase by 0.5 mg/d every wk3 mg twice dailyDizziness, drowsiness, dry mouthApproved in Canada for nausea and vomiting associated with chemotherapy.
Does not cause positive test results for cannabinoids on routine urine drug testing
  • NA—not available, SNRI—serotonin-norepinephrine reuptake inhibitor, TCA—tricyclic antidepressant, THC—tetrahydrocannabinol.

  • * Opioid initial dosing recommendations are for healthy opioid-naïve adults; opioid titration and dose range are not included owing to variability of patient and pain factors.

  • Adapted with permission from Moulin et al.7