Initiating analgesics for chronic noncancer pain

Analgesics are a second-line management strategy for chronic noncancer pain that may be considered if a patient lacks sufficient engagement with physical, psychological and social management strategies (see Chronic pain management strategies). The use of analgesics short term may help to shift engagement barriers, but can encourage patients to have a passive approach to pain management—always include self-management approaches in the individualised chronic pain management plan to encourage ongoing active management techniques; see Supported self-management for chronic pain.

In patients unable to use first-line strategies (eg a patient unable to learn self-management strategies because of severe intellectual impairment), analgesics may be required.

Consider the profile of individual drugs when deciding on the management strategy for chronic noncancer pain. Particular classes of analgesics are indicated for specific pain types:

paracetamol and nonsteroidal anti-inflammatory drugs (NSAIDs) are indicated for nociceptive pain
adjuvants are indicated for neuropathic pain.

Opioids have a limited role in the management of chronic noncancer pain, regardless of the contributing pain type (see The role of opioids in chronic noncancer pain).

Chronic noncancer pain is often contributed to by more than one pain type (ie mixed pain) or multiple mechanisms within a single pain type. Irrespective of any underlying nociceptive or neuropathic pathology, nervous system sensitisation (causing a nociplastic component) occurs in all chronic pain and is often a bigger contributor to pain than underlying structural changes—analgesics have a limited role in nociplastic pain (eg fibromyalgia, chronic unspecified low back pain).

Note: Nervous system sensitisation occurs in all chronic pain and is often a bigger contributor to pain than underlying structural changes.

There is no clear evidence for the use of multimodal analgesia in chronic noncancer pain. It may be necessary to use analgesics in combination to target different pain types (eg adjuvant analgesics for a neuropathic pain component and paracetamol for the nociceptive component) or multiple mechanisms within a single pain type (eg combining a tricyclic antidepressant and a gabapentinoid for neuropathic pain).

Before trialling an analgesic, the patient and prescriber should discuss and reach agreement on the parameters of the trial. If an opioid is considered, assess the patient’s risk of opioid misuse—a written opioid agreement may be used.

Make clear that an analgesic trial is not a long-term commitment. The patient’s response, risk of aberrant behaviours and analgesic tolerability will be assessed regularly, which is usually apparent within 1 week. A trial is considered successful (ie the analgesic is considered efficacious) if the patient has improved physical, social and vocational function together with a meaningful reduction in pain (rather than elimination)—analgesic efficacy should be apparent by approximately 4 weeks.

If the analgesic trial is successful, it may be continued short- to moderate-term (eg up to 12 weeks) until a patient has achieved self-management. If the trial is unsuccessful (ie there was no significant progress towards achieving management goals over 4 weeks), the analgesic should be deprescribed, and alternative options considered.

Note: An analgesic trial is considered successful if the patient has improved physical, social and vocational function together with a modest reduction in pain (rather than elimination).

Figure 1. Parameters of an analgesic trial for chronic noncancer pain

For any analgesic trialled for chronic noncancer pain:

the analgesic is used in conjunction with self-management strategies
management goals must be realistic (eg improved function and quality of life, a modest reduction in pain rather than elimination)
the analgesic will be stopped if there is no significant progress to management goals over 4 weeks
analgesic efficacy will be regularly reviewed
analgesic deprescribing will be trialled once self-management is achieved or at 3 to 6 month intervals—the safest way to deprescribe will be discussed with the patient.

Additional considerations if trialling an opioid:

nonopioid analgesics (eg paracetamol, NSAIDs) have been adequately trialled and are ineffective
the potential benefits of opioid therapy outweigh potential harms—if uncertain, discuss with a specialist pain medicine physician
seek specialist advice before starting an opioid trial in children or adolescents
the patient is not at high risk of an opioid-use disorder—seek specialist advice if the patient is at high risk of opioid-use disorder
- for adolescents, screen for current substance-use disorder (without parent present) using the CRAFFT questionnaire, version 2.1+N; a parent-report might be used to supplement the adolescent’s self-report, using the opioid risk assessment tool
- for adults, see Opioid risk assessment tool for adults for an opioid risk assessment tool
agreement is reached about monitoring, adherence and the consequences of nonadherence—consider a written opioid agreement
strategies to monitor adherence are defined (eg random urine drug tests, collateral histories, real-time prescription monitoring, defined intervals between prescription requests or dispensing)
even if effective, the opioid will only be prescribed for a maximum of 12 weeks, unless on specialist advice.

Note: CRAFFT = Car, Relax, Alone, Forget, Friends, Troubles

Table 1. Opioid risk assessment tool for adults Printable tool
Risk factor	YES	NO
Family history of substance abuse
alcohol	1	0
illegal drugs	1	0
prescription drugs	1	0
Personal history of substance abuse
alcohol	1	0
illegal drugs	1	0
prescription drugs	1	0
Age between 16 and 45 years	1	0
Psychiatric disorder
attention deficit disorder, obsessive compulsive disorder, bipolar disorder, schizophrenia	1	0
depression	1	0
TOTAL SCORE:
A total score of 2 or less indicates a low risk of an opioid-use disorder, whereas a total score of 3 or more indicates a high risk of an opioid-use disorder.
Note: Reproduced from Cheatle MD, Compton PA, Dhingra L, Wasser TE, O’Brien CP. Development of the revised opioid risk tool to predict opioid use disorder in patients with chronic nonmalignant pain. J Pain 2019;20(7):842-51. [URL], with permission from Elsevier

Figure 2. Written opioid agreements

Consider using a written opioid agreement with patients at high risk of an opioid-use disorder. It may outline the following principles [NB1]:

Opioid use is accompanied by active engagement in self-management strategies.
Only one prescriber and one dispenser.
No early repeats.
Lost or stolen scripts are not replaced.
Prescriptions cannot be requested by telephone.
All appointments are made in advance.
Medicines are securely stored and safely disposed of.
No lending, giving or selling of medicines.
No illicit drug use.
Medicines are taken as prescribed (ie no dose increases without involvement of the prescriber).
Random drug monitoring and pill counts may be conducted.
The opioid is started as a trial and will be discontinued if:
- treatment goals are not met
- there are serious adverse outcomes
- there is evidence of misuse
- the opioid agreement is not adhered to
- review appointments are not kept.

Note:

NB1: For an example of an opioid agreement, see the Western Australian Department of Health Schedule 8 medicines treatment contract [URL].

Adapted with permission from The Royal Australian College of General Practitioners from: Holliday S, Hayes C, Dunlop A. Opioid use in chronic non-cancer pain–Part 2: Prescribing issues and alternatives. Aust Fam Physician 2013;42(3):104–11. Available at [URL]