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Back to Table of Contents Part I: Special Concerns in Pain Management

Special Concerns

• Addiction
• Pharmacologic Tolerance
• Physical Dependence
• Pain Management among Patients with Substance Abuse Histories
• Pain that Responds Poorly to Routine Opioid Therapy

Ongoing Assessment in Pain Management

Special Concerns in Pain Management

Addiction

• The perception that the administration of opioid analgesics for pain management causes addiction is a prevalent myth that inhibits adequate pain control

• Confusion about the differences between addiction, tolerance, and physical dependence is in part responsible

• Addiction, as the term is now used, is a complex phenomenon involving:

• Psychological dependence on drugs
• Behavioral syndrome characterized by:
• Compulsive drug use
• Continued use, despite harm

• Care must be taken to differentiate a true addiction (substance use disorder) from:

• Pseudo addiction due to under treatment of pain
• Behavioural/family/psychological dysfunction
• Drug diversion with criminal intent

• To manage pain effectively, physicians will need to educate patients, families, and other professionals about the inappropriate fear of addiction

• Opioids by themselves do not cause psychological dependence
• Addiction is a rare outcome of pain management when there is no history of substance abuse

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Pharmacologic Tolerance

• Pharmacologic tolerance is the reduced effectiveness of a given dose of medication over time

• Tolerance to side effects is observed commonly and is favorable

• Tolerance to analgesia is rarely significant clinically when opioids are used routinely

• Doses may remain stable for long periods if the pain stimulus remains unchanged

• When increasing doses are required, suspect worsening disease rather than pharmacologic tolerance

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Physical Dependence

• Physical dependence is the result of neurophysiological changes that occur in the presence of exogenous opioids

• Similar outcomes occur in the presence of exogenous hormones and other medications (beta-blockers, alpha-2 agonists, etc)

• Abrupt opioid withdrawal may result in an abstinence syndrome characterized by:

• Tachycardia
• Hypertension
• Diaphoresis
• Piloerection
• Nausea and vomiting
• Diarrhea
• Body aches
• Abdominal pain
• Psychosis and/or hallucinations

• Physical dependence is NOT:

• The same as addiction
• Evidence for addiction

• Its presence does not mean that opioids cannot be discontinued

• If the pain stimulus decreases or disappears, opioid doses usually can be reduced in decrements of 50% or more every 2 to 3 days, and finally stopped


• If the dose is lowered too quickly and abstinence symptoms occur distressing symptoms may be settled with:


• A transient increase in the opioid dose,
• Treatment with clonidine, or
• A small dose of a benzodiazepine (e.g., lorazepam)

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Pain Management among Patients with Substance Abuse Histories

• Patients with histories of substance abuse can also develop significant pain, and they deserve compassionate treatment of their pain when it occurs

• Most will need to adhere to strict dosing protocols

• Contracting may become necessary

• Physicians who are unfamiliar with these situations may need the help of specialists in pain management and/or addiction medicine

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Pain That Responds Poorly to Routine Opioid Therapy

If dose escalation results in adverse effects, consider one of the following options:

• More sophisticated adverse effect therapy, such as a psychostimulant, may help sedation

• An alternate route of administration (e.g., intraspinal opioid)

• Switch to an alternative opioid ("opioid rotation")

• An adjuvant analgesic (e.g., NSAID) may help reduce the amount of opioid required

• Nonpharmacologic approaches

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Ongoing Assessment in Pain Management

• If pain control is inadequate, the dose of analgesics should be increased until either:

• Pain relief is achieved, or
• Unacceptable adverse effects occur

• In contrast with acetaminophen and the NSAIDs, there is no maximum dose of a pure agonist opioid

• If adverse effects become intolerable, effective pain control without the same adverse
  effects may be achieved through:

• An alternative analgesic
• An alternative route of administration

• Some patients will also experience less pain spontaneously or with changes in their
  underlying cause

• If the pain decreases or disappears, analgesic doses may need to be reduced or discontinued

• Driving is safe for patients who:

• Have good pain control on stable doses of an opioid
• Are not experiencing any adverse effects (especially drowsiness)

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