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Opioid
Analgesics
Opioid
analgesics are widely accepted as the preferred treatment
for acute pain and chronic pain associated with cancer. Although
the use of opioid drugs on a long-term basis to treat chronic
noncancer pain is still controversial, pain specialists now
agree that selected patients can benefit. When used appropriately,
these patients can experience sustained pain relief with tolerable
side effects and little risk of ever developing addiction.
As pain relief improves, patients may be able to function
better and experience a much improved quality of life.
As more doctors begin to consider a trial of opioid therapy
for patients with chronic noncancer pain, the need to eliminate
the stigma, the myths, and the misconceptions that surround
these drugs is a priority. Pain specialists have been working
toward this goal. The following are some key points about
opioid therapy:
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Many
people confuse physical dependence, which is the
occurrence of withdrawal when the drug is stopped, with
addiction. Withdrawal is a physical phenomenon that means
that the body has adapted to the drug in such a way that
a "rebound" occurs when the drug is suddenly
stopped. The kind of symptoms that occur include rapid
pulse, sweating, nausea and vomiting, diarrhea, runny
nose, "gooseflesh," and anxiety. All people
who take opioids for a period of time can potentially
have this withdrawal syndrome if the drug is stopped or
the dose is suddenly lowered. This is not a problem as
long as it is prevented by avoiding sudden reductions
in the dose.
Physical dependence is entirely different from addiction.
Addiction is defined by a loss of control over the drug,
compulsive use of the drug, and continued use of the
drug even if it is harming the person or others. People
who become addicted often deny that they have a problem,
even as they desperately try to maintain the supply
of the drug.
Addiction
is a "biopsychosocial" disease. This means
that most people who become addicted to drugs are probably
predisposed (it is in the genes) but only develop the
problem if they have access to the drug and take it
at a time and in a way that leaves them vulnerable.
A very large experience in the treatment of patients
with chronic pain indicates that the risk of addiction
among people with no prior history of substance abuse
who are given an opioid for pain is very low. The history
of substance abuse doesn't mean that a patient should
never get an opioid for pain, but does suggest that
the doctor must be very cautious when prescribing and
monitoring this therapy.
People with chronic pain should understand the difference
between physical dependence and addiction. Unreasonable
fears about addiction should not be the reason that
doctors refuse this therapy or patients refuse to take
it.
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Tolerance
to opioid drugs occurs but is seldom a clinical problem.
Tolerance means that taking the drug changes
the body in such a way that the drug loses its effect
over time. If the effect that is lost is a side effect,
like sleepiness, tolerance is a good thing. If the effect
is pain relief, tolerance is a problem. Fortunately,
a very large experience indicates that most patients
can reach a favorable balance between pain relief and
side effects then stabilize at this dose for a long
period of time. If doses need to be increased because
pain returns, it is more commonly due to worsening of
the painful disease than it is to tolerance.
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Although
opioids can make people sleepy and cloud their thinking,
this side effect is usually temporary and long-term therapy
is usually associated with normal thinking. Many people
fear that taking an opioid will cause them to become "a
zombie," unable to function even if the pain is relieved.
Fortunately, this is not the case. Most patients can take
these drugs for a long period of time and be mentally
normal. Patients who have been stabilized on opioid therapy
and are clearheaded can drive, work, and do whatever else
is necessary.
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Opioid
drugs are not a cure-all. Although pain specialists now
believe that many patients can benefit from this therapy,
they also recognize that some patients do poorly. Some
patients experience sleepiness or mental clouding that
never clears, and still others develop persistent nausea
or severe constipation. Some patients actually do not
function well when treated with these drugs. Finally,
some cannot be responsible drug takers; rarely, a true
addiction develops.
For all these reasons, chronic opioid therapy is generally
not a first-line treatment for patients with persistent
pain. Each patient who is a possible candidate should
be evaluated by a professional who is knowledgeable
about the use of this therapy.
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Patients
who receive a trial of an opioid drug should expect to
be carefully monitored by their physicians. Any patient
given opioid drugs to treat pain should follow the doctor's
prescription exactly. Patients should never increase the
dose on their own. They should never go to another physician
to get prescriptions and should always be completely honest
in reporting the effects produced by the drug.
The physician will inquire about pain relief; side effects;
the ability to function physically, psychologically
and socially; and the occurrence of any behavior that
suggests problems in controlling the medication. For
some patients, very intensive monitoring is appropriate;
for others, monitoring can be less intensive.
Some doctors will want the patient to agree to a contract
that describes the patient's responsibilities when taking
the drug. Some physicians will even want to monitor
the patient's urine to make sure that the patient is
taking only the drugs that should be taken. A physician
may want these things to feel secure in the knowledge
that the patient is appropriately using the drug. When
the physician is able to have this security, he or she
is free to act in the patient's best interests. A good
relationship between the physician and patient is needed
for long term opioid therapy to be successful.
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The
drugs that are now used to treat chronic pain include
morphine, hydromorphone, oxycodone, fentanyl, methadone
and others. Some opioids, like codeine and hydrocodone,
are usually prescribed in combination with acetaminophen
or aspirin. Although the latter drugs are sometimes used
for chronic pain, long-acting drugs are generally preferred.
These long-acting drugs can be taken twice a day, once
a day or, in the case of the fentanyl, by patch.
Although some people believe that opioid drugs are only
appropriate for certain kinds of pain, doctors are unable
to accurately predict which pain problems will not respond.
Each opioid produces a different range of effects in
each individual. The same person may get too sleepy
from morphine but experience very little sleepiness
from oxycodone, or vice versa. For this reason, many
pain specialists are now suggesting that patients with
chronic noncancer pain be given an opportunity to try
different commercially available opioid drugs in order
to find the drug that produces the most favorable balance
between pain relief and side effects.
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Regardless
of the opioid, the dose often has to be adjusted to get
the best effect. Patients should understand that adjustment
of the dose and the use of other medicines, like laxatives,
to treat side effects are a common part of therapy.
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