Opioids have a recognized role in treating chronic non-cancer pain. However, many physicians are reluctant to prescribe opioids, because they are concerned about the risk of addiction. This reluctance can contribute to the under treatment of chronic pain.
The risk of addiction or aberrant drug-related behavior is generally reported between 3.7 and 11.5 per cent, depending on the study (Fishbain, 2008). Although the risk of addiction is low, physicians need to know the signs of aberrant behavior, so they can recognize patients’ loss of control over their opioid medications.
Some aberrant behaviors are more predictive of addiction than others (Hojsted, 2007). They include:
- Rapid escalation of drug use
- Deteriorating function despite increasing doses
- Lack of honesty or excessive guilt
- Non-oral route of use
- Active concurrent addiction to alcohol or other substances
- Diversion and other drug dealing behaviour, including “borrowing” medications
A motivated patient can modify an opioid intended for oral use into a more bio-available form, which makes it more prone to abuse. Patients can make physical and chemical modifications to opioids, so they can be injected, inhaled, snorted and even used in rectal enemas. There are also reports of patients steeping transdermal opioid patches to make a “tea”, or cutting them for intranasal use.
Pharmaceutical companies have developed pharmacological strategies to help deter abuse, although, at this time, it is not known whether these strategies will be effective (Passik, 2009). They have physically modified formulations to make opioids more resistant to extraction, and created agonist-antagonist combinations, which reduce the “reward” at a receptor level. You should be wary if a patient requests an older version of a medication when the formulation changes.
If your patient appears to have lost control of his/her medication use, or to be at high risk of misuse, use the following strategies to help establish firm boundaries:
- Review non-pharmacologic management strategies
- Use an opioid treatment agreement
- Avoid prn doses
- Fax the prescription directly to the pharmacy
- Prescribe blister pack medications
- Shorten dispensing intervals
- Initiate random urine drug screening
- Establish realistic goals about pain reduction with opioids
- Consider referral to a chronic pain or addiction specialist
Physicians who prescribe opioids to treat chronic non-cancer pain should:
- monitor their patients on a regular basis,
- tailor therapy according to risk of misuse and response to treatment, and
- have an approach for managing aberrant behavior.
We do not advise relying solely on pharmacological properties of opioid formulations to deter misuse and abuse.
For more information on how to manage prescribing of opioids in high-risk patients and patients with addictions, please refer to the clinical review article Canadian guidelines for safe and effective use of opioids for chronic non-cancer pain: Clinical summary for family physicians. Part 2: special populations.
If you have feedback, comments or would like more information on the references cited in this month’s Prescribing Corner, please contact Dr. Susan Ulan, Senior Medical Advisor, at: 780-969-4930, 1-800-561-3899 ext. 4930 (in Alberta), or susan.ulan@cpsa.ab.ca.