JAMA -- February 9, 1994
Letters to the Editors
To the Editor---The cloning of the mu opioid receptor is a
breakthrough. It is unfortunate that the Medical News and
Perspectives(1) report on this contains misinformation about the use
of opiates in the treatment of chronic pain. Unfortunate emphasis is
given to the "possibility of finding a powerful analgesic that does
not become so quickly tolerated by the body as does morphine, which
could bring pain relief to people who suffer from chronic pain,
patients who are not normally given morphine because of the problems
of tolerance." This is not especially tantalizing to those of us
familiar with the clinical treatment of (and literature on) chronic
pain and drug dependence. Tolerance and physical dependence should not
be barriers to use of opioids in the treatment of chronic pain(2,3).
The reason that patients with chronic pain are not given
opiates when indicated is not tolerance but rather the intolerance in
our society to any ongoing use of opiates in non-terminal patients.
This has been described as "opiophobia" and is a major medical
problem. Some opiophobia may be due to a prevalent confusion between
the phenomena of physical dependence and tolerance vs the phenomenon
of addiction. Physical dependence and tolerance occur in any patient
given opioids, no matter how appropriately, for a long enough period
of time. However, in patients with no drug abuse history, after
withdrawal from long-term opiates that are no longer clinically
indicated, there is seldom any further seeking for opiates. Addiction,
on the other hand, is a neurobehavioral syndrome of compulsive seeking
and continuing use of a drug despite increasing evidence of adverse
effects. The addict will almost always return to the drug of abuse
even long after detoxification has alleviated all symptoms of
withdrawal. The nonaddicted patient weaned from narcotics after a long
period of indicated use will experience some (generally easily
managed) withdrawal symptoms and have no subsequent desire to renew
his or her acquaintance with opiates.
The prevalent confusion between physical dependence and
addiction is a pernicious influence among physicians, policy-makers,
and the general public. It significantly lowers the quality of life in
patients who are unable to find adequate pain treatment and in some
cases may even cause loss of life.(4,5) An iatrogenic syndrome
resulting from inadequate analgesia has been described, called "opioid
pseudoaddiction."(6) The patient with undertreated pain may become
progressively more demanding and hostile, exhibiting behavioral
changes that appear to the untrained eye as being those exhibited by a
drug-seeking addict rather than a frustrated patient seeking pain
relief.
The elucidation and cloning of the different opioid receptors
will have major clinical ramifications in many areas. Perhaps the
excitement generated by this discovery will lead to greater
familiarity and a better understanding among practicing physicians of
the important tools already available for the treatment of
chronic pain. Major improvements in the utilization of existing
medications could be just as important as the new analgesic drug
discoveries that will flow from this seminal biomolecular
breakthrough.
Alan I. Trachtenberg, MD, MPH
National Institute on Drug Abuse
Rockville, Md
References:
1. Randall T, Morphine receptor cloned-improved analgesics, addiction
therapy expected. JAMA. 1993;270:1165-1166.
2. Portenoy RK, Foley KM. Chronic use of opioid analgesics in
non-malignant pain: report of 38 cases. Pain. 1986;25:171-186
3. Zenz M, Strumpf M, Tryba M. Long term oral opioid therapy in
patients with chronic nonmalignant pain. JPain Symptom Management
1992;7:69-77.
4. Fishbain DA, Goldberg M, Rosomoff RS, Rosomoff HL. Homicide-suicide
and chronic pain. Clin JPain. 1989;5:275-277
5. Fishbain DA, Goldberg M, Rosomoff RS, Rosomoff HL. Completed
suicide in chronic pain. Clin JPain. 1991;7:29-36.
6. Weismann DE, Haddox JD. Opioid pseudoaddiction: an iatrogenic
syndrome. Pain. 1989;36:363-366