1. Tolerance to a drug is defined as the failure of a steady dose of the
drug over time, to sustain the desired pharmacological effect, i.e., the
need to increase the drug dosage to maintain the original pharmacological
effect. Tolerance can occur with a wide variety of drugs, including
opioids. Tolerance to the analgesic effects of opioids occur slowly, and
some clinicians think it does not occur at all in cancer patients whose
pain intensity remains stable. If pain seems to get rapidly out of control
and large doses are required to bring the pain back under control, the
pain intensity is probably increasing because of progression of the cancer.
2. Physical dependence on a drug simply means that a patient who has
received an opioid for a significant period of time will have a withdrawal
reaction (abstinence reaction) if the drug is abruptly withdrawn or if a
narcotic antagonist, such as naloxone is administered. This condition
should not be equated with "addiction." Addicted patients may be
physically dependent on a drug, but physically dependent patients are not
necessarily addicted to a drug. Physical dependence is a normal
physiological response and should be anticipated in patients whose pain
disappears and who must then be withdrawn from opioids. To avoid a
withdrawal reaction, the opioid dose should be gradually reduced. The
opioid can be given p.r.n. to treat the withdrawal symptoms, allowing the
patient to slowly taper the dose.
3. Addiction (Psychological dependence) is a term and condition that has
only social determinants. Individuals addicted to drugs make the
possession and use of drugs the paramount purpose of their lives. Addicts
readily sacrifice all their moral and ethical values for drugs. They are
willing to sacrifice resources, money, social position, job, pleasure of
eating, pleasure of sex, freedom from jail, and, finally, life itself to
drugs. This picture is quite different from that of the cancer patient in
pain who seeks drugs for the relief of his or her pain. It is rare that
someone turns to drug abuse when introduced to an opioid for medical
reasons.
Unfortunately, our society does not distinguish between the legitimate and
illegitimate uses of opioids. Therefore, any use of them is considered
bad, no matter what the reason. Patients unrelieved of pain who request,
or insist upon, adequate control of their pain are often declared morally
inferior persons, persons with weak characters, or even drug abusers by
physicians and other health care providers. This reaction should be
guarded against.
The following is taken verbatim from the Handbook of Cancer Pain
Management prepared by Weissman, Burchman, Dinndorf, and Dahl for the
Medical College of Wisconsin and the University of Wisconsin Medical
School in conjunction with the Wisconsin Cancer Pain Initiative and the
World Health Organization. It describes the condition of
"pseudoaddiction":
"Opioid pseudooddiction " is a common iatrogenic syndrome in which
patients develop certain behavioral chraracteristics of psychological
dependence as a consequence of inadequate pain treatment. This may occur
as a result of 1) prn dosing during periods of continuous pain and/or 2)
the use of dosing intervals which are greater than the duration of action
of a given analgesic and/or 3) the use of insufficiently potent
analgesics. Patients with this syndrome must continually demonstrate their
need for analgesics and are often described as difficult patients, chronic
complainers and/or "addicts ". Patients will often resort to bazaar or
dramatic behavior- (acting out) in an attempt to prove their pain is real
so that analgesics will be administered. Consequences to the patient if
this syndrome is not recognized and treated include a loss of trust in the
health care team and feelings of isolation, fear and anger. Treatment
involves breaking the vicious cycle of mistrust, and realization by the
health care team that psychological dependence (addiction) should not be a
consideration in deciding the proper dose and schedule of opioids.
Specific measures include 1) establishing trust between patient, nurse and
physician that pain can and will be controlled, 2) using scheduled
("around the clock ") analgesics of sufficient potency to provide adequate
analgesia, 3) using oral drugs whenever possible and 4) frequent
reassessment of the pain and level of analgesia.
Note: Short acting opioids (morphine, hydromorphone, oxycodone and codeine) are frequently prescribed at an ineffective dosing interval of every 6-8 hours in the mistaken belief that this will prevent or delay the onset of tolerance, physical, or psychological dependence. As noted above, this prescribing pattern will lead to undertreatment of the pain and potentially cause the behavior pattern seen in cases of "pseudoaddictionî."
