The role of long-term opioid therapy for chronic nonmalignant pain is
evolving. Pain specialists now strongly endorse the view that opioid therapy
can be safe and effective in a subgroup of patients with chronic pain.
This acceptance must be balanced by the acknowledgement that side effects
often are a problem and that the drugs may become the objects of abuse
and even addiction in predisposed individuals. Any clinician who wants
to be able to provide selected patients with this therapy must acquire
basic skills in both the principles of opioid prescribing and the assessment
and management of risk.
Some types of neuropathic pain may be relatively less responsive to opioid
drugs, but the claim that these syndromes are opioid resistant, which
has appeared in the literature, is incorrect. There are randomized controlled
trials demonstrating the efficacy of morphine, oxycodone, levorphanol,
and tramadol in various types of neuropathic pain. There have been positive
randomized, placebo-controlled trials of oxycodone and tramadol in diabetic
painful polyneuropathy. In the study of controlled-release oxycodone,
study medication was titrated every 3 days until the preferred maximum
dose was attained. At an average dose of 37 mg/day (range 0-99 mg/day),
the opioid provided significantly more analgesia than placebo, as evidenced
by better pain scores, more satisfaction with medication, and significant
decreases in pain interference with social relationships, enjoyment of
life, and quality of sleep.
The selection and management of long-term opioid therapy for chronic nonmalignant
pain should be guided by a set of principles that help define the selection
criteria, the need for individualization of the dose, and the structure
for monitoring.
Considerations in the Use of Opioid Therapy for Chronic Pain
- Patients with moderate to severe pain may be potential candidates
for opioid therapy. Physicians can formulate a clinical judgment based
on responses to the following questions:
- What is the likelihood that opioid therapy will be effective based
on past clinical experience, pertinent medical literature, and characteristics
of the pain (i.e., etiology and pathophysiology)?
- Are other therapies likely to work as well, and have there been
adequate trials of those therapies with this patient?
- What are the risks of opioid therapy in this patient, and do the
likely benefits of opioid therapy outweigh the potential risks?
- Is the patient likely to demonstrate responsible drug taking?
- If the evaluation raises concerns about the appropriateness of therapy
or a suitable way to monitor therapy, consider referral to a pain management
program or addiction medicine specialist for advice before initiating
therapy.
- A single clinician, who has reviewed all medical records, should take
primary responsibility for opioid prescriptions; the prescriber should
have the skills necessary to optimize the therapy according to accepted
principles and guidelines, and perform risk assessment and management
on an ongoing basis.
- Patients need to be educated about opioid therapy, and clinicians
should document the consent discussion, which might cover:
- the need for monitoring and adherence to instructions
- information about physical dependence and addiction
- the potential for side effects (e.g., cognitive impairment and constipation)
- Some clinicians use an opioid agreement as a tool to inform patients
about the structure for therapy, the nened for adherence and the consequences
of nonadherence; other clinicians do not endorse the use of this tool,
but document the consent discussion and rely on subsequent communication
with the patient to provide the education and oversight.
- Therapy can start after the provider performs a clinical evaluation
of potential risk associated with abuse or addiction. This provides
a structure to the therapy that enforces a degree of control and monitoring
that is commensurate with the perceived risk.
- Opioid therapy should be implemented according to well-accepted principles
for prescribing, including a comprehensive pain assessment, selection
of an appropriate drug and route, individualization of the dose by repeated
dose titration, assessment and treatment of common side effects, and
monitoring of outcomes over time.
- Patients may need access to a “rescue dose” for breakthrough
pain. This decision should be made on a case-by-case basis after assessment
of the pain syndrome, opioid requirements, and the likelihood of responsible
drug use. If rescue doses are not prescribed, patients may take one
or two extra doses on a day of increased pain, which must be followed
by an equal reduction of doses on subsequent days.
- At each encounter, the healthcare provider should thoroughly assess
and document the following:
- comfort (degree of analgesia)
- opioid-related side effects
- functional status (physical and psychosocial)
- occurrence of problematic drug-related behaviors
- Providers should reassess patients with no substantial prior opioid
exposure who fail to achieve at least partial analgesia at relatively
low initial doses of an opioid. This failure raises questions about
the potential treatability of the pain syndrome with opioids. Some patients
are outliers with severe pain, who respond appropriately to dose escalation;
others, however, demonstrate responses that raise questions about the
effectiveness or appropriateness of opioid therapy. Recognize the variations
in responsiveness.
- Although providers should continually stress improvement in function,
they should accept meaningful partial analgesia without a decline in
function as the appropriate minimal goal of therapy. They will emphasize
attempts to capitalize on improved analgesia by gains in function. Opioid
therapy is only one of multiple modalities that can be used.
- If problematic drug-related behaviors occur, the clinician will carefully
assess the patient to better understand the factors that contribute
and the existence of any psychiatric or medical comorbidities. Depending
on the assessment, some patients are best managed by tapering and discontinuing
the opioid therapy, and others may appropriately continue therapy within
rigid guidelines. Clinicians may consider consultation with an addiction
medicine specialist.
References
Gimbel JS, Richards P, Portenoy RK: Controlled-release oxycodone for pain
in diabetic neuropathy: A randomized controlled trial. Neurology 60(6):927-34,
2003.
Kalso E, Allan L, Dellemijn PL, et al. Recommendations for using opioids
in chronic non-cancer pain. Eur J Pain. 2003;7:381-386.
Portenoy RK. Opioid therapy for chronic nonmalignant pain: a review of the
critical issues. J Pain Symptom Manage 1996;11(4):203-217.
Portenoy RK, Payne R, Passik S: Acute and chronic pain. In Lowinson JH,
Ruiz P, Millman RB (eds): Comprehensive Textbook of Substance Abuse, Fourth
Edition. Baltimore: Williams and Wilkins, in press.
Watson CP, Moulin D, Watt-Watson J, Gordon A, Eisenhoffer J. Controlled-release
oxycodone relieves neuropathic pain: a randomized controlled trial in painful
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