McMaster University

Michael G. DeGroote
National Pain Centre

Scope of Search

Canadian Guideline for Safe and Effective Use of Opioids for Chronic Non-Cancer Pain

Cluster 2: Conducting an Opioid Trial

R11. Recommendation Statement

No. Recommendation Keyword

When initiating a trial of opioid therapy for patients at higher risk for misuse:

  • Prescribe only for well-defined somatic or neuropathic pain conditions (Grade A)
  • Start with lower doses and titrate in small-dose increments (Grade B)
  • Monitor closely for signs of aberrant drug-related behaviors (Grade C)
Risk: opioid misuse
  • R11. Discussion
  • R11. Summary of Peer-Reviewed Evidence

R11. Discussion

1. Indicators of Patients at Higher Risk of Opioid Misuse

The following factors could indicate patients at higher risk of opioid misuse:

  • History of alcohol or substance abuse (patient and/or family)
  • Uncertain security in the home (e.g., living in a boarding home with minimal protection for possessions)
  • Past aberrant drug-related behaviours (see Recommendation 12)

For patients at higher risk of misuse, ensure that:

  • Opioids have shown to be effective for the patient’s diagnosis(es) (See Recommendation 4 for an overview of evidence of opioid efficacy).
  • All other available treatment options have been exhausted.

2. Titration for Patients with Higher Risk of Opioid Misuse

In these higher-risk cases, start the titration at lower doses, increase in smaller quantities, and monitor more frequently. Careful opioid prescribing will limit both diversion and misuse of prescribed medications. Also, since the euphoric effects of opioids are dose-related, minimizing the dose may reduce the risk of opioid misuse by reducing patients’ exposure to the reinforcing psychoactive effects of opioids.

A further precaution could include prescribing at frequent dispensing intervals, e.g., daily, alternate days, twice per week, or every 1–2 weeks.

3. Monitoring Patients with Higher Risk of Opioid Misuse

Extra cautions could include:

  • Asking the patient to bring their medication for pill counts and to explain any discrepancies
  • Using screening tools to check for aberrant drug-related behaviours (see Appendix B-10)

R11. Summary of Peer-Reviewed Evidence

1. Prescribing strong opioids has increased substantially in many regions throughout North America. This has been accompanied by a major increase in prescription opioid misuse and addiction.

Evidence from multiple sources suggests that North America is witnessing a major increase in prescription opioid misuse and addiction. For example, the Drug Abuse Warning Network in the United States has documented a seven-fold increase in emergency department visits and overdose deaths related to oxycodone (Gilson 2004, Paulozzi 2006). Increases in opioid abuse were also documented by the Purdue-sponsored RADARS system using addiction experts as key informants (Cicero 2005). A prospective Canadian study found that illicit opioid users are more likely to use prescription opioids than heroin (Fischer 2006). In the United States, the number of prescription opioid users entering addiction treatment rose from 14,000 in 1994 to 60,000 in 2004 (Maxwell 2006).

2. Physicians’ prescriptions are a significant source of abused opioids.

Hall et al. conducted a population-based, observational study of unintended pharmaceutical overdose fatalities in West Virginia. Of the 295 decedents, opioid analgesics were taken by 275 (93.2%), of whom only 122 (44.4%) had ever been prescribed these drugs. Pharmaceutical diversion was associated with 186 (63.1%) deaths, while 63 (21.4%) were accompanied by evidence of doctor shopping (Hall 2008).

In studies of patients admitted to a treatment program for prescription opioid addiction, physicians’ prescriptions were a common source of opioids (Brands 2004, Passik 2004, Rosenblum 2007). Most had also received opioids from friends, family or dealers, although it is not known how many of these non-medical sources had received their opioids from physicians’ prescriptions.

In 2006, Dasgupta et al. published a study using national data from the Drug Abuse Warning Network (DAWN). They showed that the non-medical use of prescription analgesics was directly associated with the potency-adjusted total amount of opioids in prescriptive use. This data suggests that non-medical use of opioids is predictable based on potency and extent of prescriptive use (Dasgupta 2006).

3. The reinforcing psychoactive effects of opioids are dose-related. 

In a retrospective case-control study, opioid-dependent patients had much higher ratings of euphoria on their first exposure to opioids for chronic pain than controls who were not opioid dependent (Bieber 2008). This suggests that a subgroup of patients experience euphoria when prescribed opioids and this group is at greater risk for becoming dependent on them. Controlled studies in healthy volunteers have demonstrated that the cognitive and euphoric effects of opioids are dose related, both in non-drug using volunteers and in former opioid addicts (Zacny 2003, Lamb 1991).