The role of adjuvants for chronic noncancer pain
Adjuvants must be used in conjunction with self-management approaches for chronic noncancer pain and are not effective for all patients.
The role of adjuvants for chronic noncancer pain in children under 18 years of age is not within the scope of this guideline. High-quality evidence for efficacy of adjuvants in children is lacking. Seek specialist advice before using an adjuvant in children with chronic noncancer pain because the benefit–harm profile of adjuvants is generally unfavourable (see Commonly used adjuvants in pain management for more information)1.
In adults, there is evidence supporting the use of adjuvants for chronic noncancer pain with a neuropathic component. There is limited evidence supporting the use of adjuvants for nociplastic pain conditions (eg chronic low back pain, fibromyalgia)—adjuvants provide limited analgesic benefit and efficacy varies according to the specific condition.
Advise patients to consult the prescriber if adverse effects are intolerable. Response to adjuvants may not be apparent in the early weeks of treatment. Review the analgesic efficacy after 4 to 6 weeks. Deprescribe the adjuvant if it is ineffective or not tolerated, there is concern about dependence, or it is suspected that the adjuvant is being misused or abused. Consider trialling another adjuvant.
Although the evidence for combination therapy is limited, it may be necessary to use two oral adjuvants concurrently. If adjuvant monotherapy provides a partial response, but pain relief is still inadequate, consider adding a second adjuvant.
Lidocaine 5% patches are preferred to oral adjuvants if the patient has localised neuropathic pain (eg postherpetic neuralgia, nerve entrapment). For localised neuropathic pain in adults, use:
lidocaine 5% patch, up to 3 patches applied at the same time to the painful area. Wear for up to 12 hours, followed by a patch-free interval2. chronic noncancer pain, neuropathic lidocaine
If a gabapentinoid is appropriate for chronic noncancer pain in adults, use:
1 gabapentin 100 to 300 mg orally, once daily initially. Increase at 3-to 7-day intervals to twice daily then 3 times daily as tolerated and according to response. If needed, continue to increase the dose at 3-to 7-day intervals to a maximum maintenance dose of 3600 mg in 24 hours. If the patient is frail or older than 70 years, use the lower end of the dose range initially, titrate more slowly and do not exceed a maximum dose of 900 mg in 24 hours3 chronic noncancer pain, neuropathic gabapentin
OR
1 pregabalin 25 to 75 mg orally, in the early evening initially. Increase to twice daily after 3 to 7 days. If needed, continue to slowly increase the dose as tolerated and according to response, up to a maximum maintenance dose of 600 mg in 24 hours. If the patient is frail or older than 70 years, use the lower end of the dose range initially, titrate more slowly and do not exceed a maximum dose of 300 mg in 24 hours4. chronic noncancer pain, neuropathic pregabalin
If a tricyclic antidepressant (TCA) is appropriate for chronic noncancer pain in adults, use:
1 amitriptyline 5 to 12.5 mg orally, at night. Increase every 7 days, as tolerated and according to response, up to 50 mg at night. If no pain relief is achieved, discontinue treatment. If some pain relief is achieved, continue to increase the dose every 7 days, as tolerated and according to response, up to 150 mg at night. If the patient is frail or older than 70 years, use the lower end of the dose range initially and titrate more slowly chronic noncancer pain, neuropathic amitriptyline
OR
1 nortriptyline 5 to 12.5 mg orally, at night. Increase every 7 days, as tolerated and according to response, up to 50 mg at night. If no pain relief is achieved, discontinue treatment. If some pain relief is achieved, continue to increase the dose every 7 days, as tolerated and according to response, up to 150 mg at night. If the patient is frail or older than 70 years, use the lower end of the dose range initially and titrate more slowly. chronic noncancer pain, neuropathic nortriptyline
If an SNRI is appropriate for chronic noncancer pain in adults, use:
1 duloxetine 30 mg orally, in the morning. Increase every 7 days, as tolerated and according to response, up to 120 mg in the morning chronic noncancer pain, neuropathic duloxetine
OR
1 venlafaxine extended release 37.5 to 75 mg, in the morning. Increase every 7 days, as tolerated and according to response, up to 225 mg in the morning. chronic noncancer pain, neuropathic venlafaxine
If adjuvant therapy is effective, the adjuvant(s) may be continued short- to moderate-term (eg up to 12 weeks) until a patient has achieved a supported self-management approach. Some patients with permanent nerve damage (eg spinal cord injury) may require therapy for longer than 12 weeks, with a supported self-management approach. Trial deprescribing every 3 to 6 months to assess ongoing efficacy attributable to the adjuvant, and reduce the risk of long-term adverse effects.
Seek specialist advice if two oral adjuvants have been ineffective or are not tolerated after an adequate trial, or if the patient is not achieving a self-management approach.