by Jay Ellis, MD
Few topics in pain medicine generate as
many disagreements as the use of chronic
opioid therapy for chronic pain not
due to cancer. Why would experts devoted
to the care of chronic pain patients
disagree so fervently about the wisdom
of giving opioids to a patient with
chronic pain? The controversy arises not
so much from the accepted facts about opioid therapy, but
rather in the interpretation of those facts and the application
of the facts to the lives of the patients.
Do opioids work for benign chronic pain? The philosopher
says, “First, define your terms.” Whether opioids work
depends on the therapeutic endpoint sought by the patient
and the physician. Proponents of opioid therapy point out
that patients with chronic pain on opioid therapy report
lower pain scores, improved quality of life and better sleep
when started on opioid therapy.
Evidence based algorithms for neuropathic pain, such
as diabetic neuropathy and post-herpetic neuralgia list
opioids, especially sustained release oxycodone and tramadol,
as second or third line treatment agents. Critics
of opioid therapy point out that the studies of pain relief
in chronic pain patients are of short duration, weeks to
months, and that there is a shortage of good longitudinal
studies. Observational studies such as a recent study
from Denmark suggest there may be negative long-term
health impact from chronic opioid therapy. Critics further
argue that opioid therapy seldom results in significant
functional improvement, and proponents of opioid
therapy agree that functional improvement is modest
at best.
Critics of opioid therapy further argue that the effect
size, or degree of pain relief, with opioid therapy is often
modest and lies in the 30 to 50 percent range for absolute
reduction of pain scores. Proponents of opioid therapy
counter that the same could be said for nonsteroidal
anti-inflammatory medications, antidepressants and
antiepileptic medications, which show pain reduction of
a similar magnitude.
Critics of opioid therapy argue that many patients with
chronic pain would benefit more from physical therapy,
exercise, psychological counseling and treatment of psychosocial
problems. Proponents of opioid therapy agree
that those therapies are an important part of any therapeutic
plan, and that if such treatments were uniformly successful
there would be no need for opioid therapy. Patients
on opioid therapy are individuals who have no other effective
treatment.
What are the side effects/risks? Like all treatments, chronic
opioid therapy has side effects and risks. The three issues
that attract most discussion are tolerance, dependence and
addiction. The terms are not interchangeable and space limitations
prevent a full discussion of each term.
Tolerance, a physiologic response to the medication
resulting in dose escalation can occur in some patients, and
seems to be more of a problem in younger patients. It
should be treated as a therapeutic failure and the patient
should be weaned off opioids or considered for an alternative
agent.
Dependence does develop in almost all opioid patients
and will result in an abstinence syndrome if the medication
is halted abruptly. This is a phenomenon seen in other
medications (steroids, clonidine). Addiction, the major concern
among many practitioners, does occur in 2 to 13 percent
of patients, depending on the definition used and
method of detection.
Critics of opioid therapy find this to be an unacceptable
complication rate. Proponents of opioid therapy point out
that it compares favorably with complication rates for long
term NSAID therapy and the rate of addiction is equal to
reported rates of illicit drug use in the general population.
Proponents argue that the risk is justified when no better
alternative is available. Other side effects of opioid therapy
include cognitive dysfunction, constipation, suppression of
hormonal secretion (especially testosterone) and opioid
induced hypersensitivity. These side effects must be balanced
against the benefits of therapy.
What should the doctor do? The decision to start a
patient on chronic opioid therapy is not unlike a decision
to embark on other treatments with significant risk, such as
surgery or chemotherapy. The physician and patient must
evaluate all of the treatment options available to them.
There must be full disclosure of all potential risks and side
effects along with a statement of the anticipated benefits. If
the patient fails to respond due to lack of therapeutic benefit,
intolerable side effects or development of abuse behavior,
then therapy should be terminated with a gradual taper
of the medication.
Not all patients are good candidates for opioid therapy
Patients with a history of substance abuse and patients with
significant untreated psychiatric disorders are especially
problematic. Older patients do better than younger ones.
Some disorders (fibromyalgia, muscle tension headaches)
respond poorly to opioid therapy. Despite these misgivings,
opioid therapy does provide selected patients with less pain
and mild improvements in functional capacity. Denying
chronic opioid therapy to all patients is no less a mistake
than giving it to all chronic pain patients.
Jay Ellis, MD is a private practice Pain Management Physician/
Anesthesiologist with the River City Division of Tejas Anesthesia.
He is also a Clinical Professor of Anesthesiology/Pain Management
with the University of Texas Health Science Center at San
Antonio and has been treating pain patients for 20 years.
