++
Many older patients experience pain daily, yet they receive inadequate
analgesia. Although many older people have a higher incidence of
side effects, this is not a good excuse for undertreatment. Analgesics
can still be used, but should be used more wisely and cautiously.
The following guiding principles and caveats have been extracted
from the American Geriatrics Society Clinical Practice Guidelines,
and may help maximize treatment efficacy and minimize adverse effects
in the elderly.22 These principles are summarized
in Table 57-3.
++
+++
Principle 1:
A Little Goes a Long Way
++
Hepatic and renal function is often reduced as a normal part
of aging. This results in a higher peak plasma level, as well as
a longer half-life of many drugs. For example, peak plasma levels
of oxycodone are 15% greater in elderly than in younger
patients. Persons with a creatinine clearance <60
may have peak plasma levels that are 20% to 50% higher.
Thus elderly patients may achieve pain relief from smaller doses
of analgesics than those required by younger patients. Therefore,
if the pain is mild to moderate, an opioid-naïve elderly
person may have a good response with a half tablet to one tablet
of oxycodone or hydrocodone. Although the patient may ultimately
need higher doses for adequate pain relief, the old adage “start
low and go slow” accurately reflects the need for gradual
and careful titration. Extra caution should be taken when converting
to long-acting forms of analgesics because of the problem of drug
accumulation.
+++
Principle 2:
Use Standing Doses
++
Medications written as pro re nata (prn) often assume that the
patient knows when to take or ask for analgesics, which is not often
the case, particularly in those with cognitive impairment. This often
results in unnecessary suffering. If the pain is experienced at
predictable times in the routine of their day, or if there are known
triggers, it is better to use standing doses of analgesics to prevent
pain. For example, if the person experiences pain mostly during
the morning routine of getting up, but are more sedentary most of
the day, the standing dose should be taken an hour before arising.
If the pain is steady and continuous, analgesics should be used
around the clock.
+++
Principle 3:
Be Compulsive About Assessing Pain and Side Effects
++
Reassessment of pain relief and side effects should be performed
within hours to days, especially during initiation, titration, or
after any change in analgesic medications. Adjustments may include changing
the drug, dose, or timing of the medication. The assessment of side
effects should be performed at the same time. Because we are working
with a frailer population in whom drug accumulation occurs easily,
adverse effects are more common and more devastating (e.g., confusion,
falls), the importance in assessing side effects cannot be emphasized
enough, especially when converting to a long-acting form of the
drug.
+++
Principle 4:
Involve the Caregivers
++
Finally, it is important to include the primary caregivers in
the treatment plans because not only are they the gatekeepers of
medicines, they also watch for efficacy and side effects. We should give
clear written instructions about assessment and materials that explain
potential side effects of medications. Without their full understanding
and cooperation, it is not uncommon for bad experiences to cause
the patient or their family to fear the drug, and lead to noncompliance
and needless suffering later on.
+++
Analgesic Drugs
in the Elderly
++
This section provides descriptions of examples of drugs to avoid,
as well as those with favorable side-effect profiles for the elderly.
++
Acetaminophen is the drug of first choice for mild to moderate
pain in the elderly. Acetaminophen can be used safely in the elderly
up to 4000 mg a day, and must be used cautiously in persons with
liver failure. However, there are no gastrointestinal (GI), renal,
bleeding, or cognitive side effects compared with nonsteroidal anti-inflammatory
drugs (NSAIDs). Acetaminophen has been demonstrated to be equally
efficacious in treating osteoarthritis pain as ibuprofen, both at analgesic
and anti-inflammatory doses.23
++
Unfortunately, NSAIDs are not as safe as acetaminophen. Common
side effects include GI bleeding, renal impairment, constipation,
dizziness, and confusion in the elderly. Among NSAIDs, the nonacetylated
salicylate preparations such as salsalate and trisalicylate are
preferred because they seem to cause less GI erosion and platelet
dysfunction.24–36 Renal toxicity of NSAIDs
also should be considered. Since elderly people are more dependent
on prostaglandins to maintain renal blood flow, the prostaglandin-inhibiting
effects of NSAIDs may reduce glomerular filtration rate and lead
to significant azotemia. This adverse effect occurs most frequently
among patients taking diuretics or with a history of congestive
heart failure. Because creatinine clearance decreases with age,
an otherwise healthy 85-year-old person most likely has a calculated
creatinine clearance of <40. However, if one still
decides to use NSAIDs, we recommend that it be given at half the
dose, at half the frequency, and with GI prophylaxis. Patients at
high risk of gastrointestinal toxicity include persons older than
60 years old, those with a prior history of ulcers or GI bleeding,
or those taking corticosteroids or anticoagulation. Misoprostol
(Cytotec) is recommended to prevent both gastric and duodenal ulcers
caused by NSAIDs at doses starting at 100 to 200 μg
twice daily. Proton pump inhibitors (Prilosec, Prevacid) are also
effective, and are less likely to cause diarrhea. H2-blockers,
sucralfate, or antacids are not effective in preventing gastric
ulcers caused by NSAIDs.27
++
There is a new class of anti-inflammatory drugs known as Cox-2
inhibitors. These are reportedly less likely to cause significant
bleeding and ulcers than other NSAIDs. Furthermore, they do not seem
to affect platelet aggregation or interact with warfarin. However,
they can cause similar kidney effects including fluid retention
and edema, and some remaining Cox-1 inhibitory activity may place
the gastric mucosa at risk for bleeding. Although promising, lower
doses should be used until more experience is accumulated in frail
elderly populations.28,29
++
Drugs used to treat moderate to severe pain include preparations
of acetaminophen or aspirin, which are combined with opioids such
as codeine (e.g., Tylenol #3), oxycodone (e.g., Percocet), hydrocodone
(e.g., Vicodin), or propoxyphene (e.g., Darvon). These combinations
augment the efficacy of the opioid. However, there are some preparations
we prefer not to use in the elderly, as they often cause more toxicity
compared with other preparations. For example, codeine seems to cause
more nausea and constipation.30,31 Propoxyphene
is not recommended for use in the elderly since it is no better
than aspirin or acetaminophen, and has the potential for development
of dependency, renal injury, as well as considerable toxicity. The
use of propoxyphene can be dangerous because it interacts with antidepressants,
anticonvulsants, and warfarin-like drugs to raise serum levels of
these agents. Furthermore, there is also a problem of toxic metabolite
accumulation. Its metabolite, norpropoxyphene, has a half-life of
30 to 36 hours and can cause PR and QRS prolongation.32 Drugs
with mixed agonist-antagonist receptor activity such as pentazocine
(e.g., Talwin) and butorphanol (Stadol) should never be used, as
these frequently cause delirium and agitation in older persons.33
++
Caution should be used with tramadol (Ultram) as well. Although
it is not technically an opioid, it has an efficacy similar to codeine.
Its mechanism of action is on opioids, norepinephrine and serotonin
receptors.34 Until there is more experience in
the older population, caution should be used with higher doses, and
should be avoided in persons with seizure risks and those already
taking selective serotonin reuptake inhibitors or tricyclic antidepressants.
++
Of all the opioids used for the treatment of moderate to severe
pain, morphine, oxycodone, and hydromorphone are preferred. Demerol
should never be used in the elderly, because it is associated with
an increased risk of delirium and seizure activity, and has a long-acting
and toxic metabolite, normeperidine.35,36 Furthermore,
Demerol often gets used with Vistaril to combat the problem of nausea.
However, the anticholinergic activity of these drugs increases the
risk of delirium.
++
The use of long-acting forms of opioids, such as MS Contin, OxyContin,
should only be considered when the pain is stable and the opioid
requirement is consistent for at least 48 to 72 hours. Because drug
accumulation commonly occurs in elderly people, as a rule of thumb,
one should use about 75% of the calculated 24-hour requirement
when switching to the long-acting form, and cover the difference
with a short-acting medication. The caveat should also be applied
when switching to different opioid classes because cross-tolerance
is incomplete.
++
Similarly, the fentanyl patch (Duragesic) should be used cautiously
in the elderly. When the same doses were given to both elderly and
young subjects, the serum concentrations were over two times higher
in the older population.37 Although reduced amounts
of subcutaneous fat may decrease the absorption of fentanyl, low
protein stores associated with poor nutrition results in higher
levels of free drug in the circulation. The combination of increased
drug levels and decreased clearance results in more potent opioid
effects in the elderly. The use of a 25-μg patch is
dangerous in an elderly opioid-naïve patient and increases
the risk of delirium, sedation, falls and aspiration. We advise
switching to the 25-μg patch only when the morphine
requirement is calculated to be consistently about 80 to 90 mg/day
over the previous 48 to 72 hours.
+++
Anticipate and
Treat Side Effects
++
Because side effects from opioid use occur more frequently in
the elderly, we need to anticipate, monitor, and treat side effects
efficiently. All efforts to use the minimum effective dose should
be taken. This may include the consideration of more invasive procedures
(e.g., hip or knee surgery, steroid injections, or viscosupplementation),
if the patient is determined to be a suitable candidate.
++
Constipation with opioid use is almost always inevitable in the
elderly. Tolerance does not occur; therefore prophylactic use of
both stool softeners and peristaltic agents is recommended. Ambulation
and physical exercise also helps constipation.
++
Nausea is also common; however, tolerance may develop in 5 to
7 days. So for those who have trouble with nausea, smaller doses
of opioids should be used initially. Patients should also be evaluated
and treated for other causes of nausea (e.g., gastritis, CNS swelling,
chemotherapy). If necessary, the smallest doses of metochlopramide
(Reglan 5-mg tablet), prochloperazine (Compazine 5-mg tablet), or
promethazine (Phenergan 12.5-mg tablet) should be used sparingly.
These agents, however, are not encouraged because they have anticholinergic
activity. Dehydration occurs easily in the elderly; therefore fluid
intake should be monitored carefully.
++
Sedation is also common, but like nausea, tolerance develops
after a few days. However, this could be compounded by other medications
that could be adding to the sedative effects of the opioid. Because
of the increased risk for automobile accidents, falls, and other
accidents, patients should be evaluated for safety, and efforts
toward reducing or discontinuing other sedating medications should
be undertaken. If this is not possible, we recommend changing the
dosing schedule to minimize administering sedating medications during
the daytime. Addition of adjuvant medications may also help minimize
opioid requirements. If the person does not have severe or unstable
cardiac disease, one could consider a trial of Ritalin at low doses
(e.g., 5 to 10 mg once or twice a day).
++
Delirium is more common among patients with underlying dementia.
Other causes of delirium should be considered, such as medications,
infections, and concurrent illnesses. Anticholinergic drugs that
may be contributing to the problem should be stopped if possible.
Some of the most anticholinergic drugs include diphenhydramine (Benadryl),
amitriptyline (Elavil), doxepin (Sinequan), cyclobenzaprine (Flexeril),
dicyclomine (Bentyl), hyoscyamine (Levsin), and trimethobenzamide
(Tigan).38 Otherwise, one should use the minimum
effective opioid dose, try adding an adjuvant, or consider switching
to a different opioid.
++
Neuropathic pain is opioid-resistant. Because larger doses of
opioids are needed to achieve relief, the person is often better
off using adjuvants such as antidepressants or anticonvulsants.
There are a few antidepressants that should be avoided. Although
amitripyline has been found to be very effective for neuropathic
pain, it is also the most highly sedative and anticholinergic of
all the tricyclic antidepressants. Doxepin and imipramine are both
moderately sedating and anticholinergic. Use of secondary amines
such as desipramine and nortriptyline are recommended because not only
do they have the lowest incidence of sedation and anticholinergic
side effects, they are effective as well. Max et al demonstrated
that desipramine and amitriptyline were equally efficacious in treating
diabetic neuropathy.39 In the elderly, these drugs
should be started at one half to one third of the usual adult starting dose.
++
Anticonvulsants such as carbamazepine and valproate are both
widely used and have well-established efficacy in the treatment
of neuropathic pain. But two other agents might be considered early
on because of their very low toxicity: clonazepam, a benzodiazepine,
and gabapentin. The only major drawbacks of clonazepam are sedation
and ataxia. Gabapentin is a newer anticonvulsant, which has been
shown to be effective for peripheral neuropathic pain due to diabetes
and postherpetic neuralgia. This drug is preferred in the elderly
for several reasons: Gabapentin does not have significant interactions
with commonly prescribed medications; it has few side effects; and
there is no need to monitor levels. It can also be used in conjunction
with low-dose tricyclic antidepressants to augment efficacy. Because
it can cause dizziness, drowsiness, and ataxia, we recommend starting
with doses as low as 100 mg once or twice a day, and titrating up
slowly.40,41
++
Other adjuvants include steroids for pain from spinal cord compression,
soft tissue infiltration, acute nerve compression, or brain tumors.
Steroids also help nausea, anorexia, and lethargy. For bony pain
from compression fractures, calcitonin nasal spray is a useful adjuvant.
It can be used as a nasal spray at 200 IU every day, or given as
a subcutaneous injection at 100 IU every day.42 Topical
preparations include capsaicin cream. Because it depletes substance
P from nerve endings, capsaicin enhances pain control when added
to systemic treatment for osteoarthritis, rheumatoid arthritis,
diabetic neuropathy, or postherpetic neuralgia.43–46 It
also appears to be beneficial for other painful cutaneous disorders
such as cluster headache, postmastectomy pain, amputation stump
pain, and skin tumors.47 Unfortunately, capsaicin
is often limited in use because of the initial burning it causes
or the need for frequent application.
+++
Nondrug Pain
Management
++
Nondrug approaches are an important part of the pain management
strategy in the elderly for several reasons: Nondrug strategies
augment the efficacy of medications; have few adverse effects; give
the patient and family a sense of participation and control; and
addresses problems of functional decline, mood, and social isolation.
An effective program must begin with patient and family education.
The clinician should dispel misconceptions that pain, physical disability,
and social isolation are normal parts of aging. There should be
discussions with the patient, family, and other caregivers concerning
the cause of the pain, pain assessment, medication use and side
effects, goals of treatment, and use of self-help techniques such
as heat, cold, massage, relaxation, and distraction.
++
Multidisciplinary pain clinics are an important resource in helping
patients deal with the functional and psychosocial sequelae of chronic
pain, instead of merely focusing on finding a magic cure. Treatments
often include physical and occupational therapies, biofeedback,
relaxation techniques, psychological support, and cognitive-behavioral
therapy (e.g., education about coping mechanisms, stress management,
communication skills). Although such programs often result in significant
improvement in pain, reduction of health care utilization and less
medication use,48 few elderly are actually enrolled
in multidisciplinary pain clinics.49 One misconception
is that older people may be less willing to participate in multidisciplinary
treatment. However, studies have demonstrated that when elderly
patients were offered participation in multidisciplinary pain clinics,
they were as equally likely to accept participation as the younger
population. Furthermore, cooperation with treatment, including the
psychiatric components, was good, with dropout rates similar to
the younger population.50 We need to find ways
of adapting our programs to include those of similar ages and shared
experiences.
++
Although persons with cognitive impairment may not be able to
participate in some of the more cognitive therapies, there are strategies
that can be used even among persons with dementia. Exercise is one
of the most important interventions. Although many older people
assume that exercise is an activity for younger persons, exercise
in older persons has been shown to have many benefits, including
reduction of pain symptoms and amelioration of depression. In a
study of community dwelling persons older than 60 years old with
self-reports of pain, physical disability, and radiographic evidence
of osteoarthritis, enrollment in an exercise program was clearly
better than education in relieving pain. Both aerobic and resistance
exercises resulted in modest improvements in physical disability,
pain, and objective measures such as improved time to climb or descend
stairs, and greater walking distances in a timed 6-minute walk.51 Not
only does exercise reduce contractures, weakness, fatigue, recurrent
falls, and help with problems such as insomnia and constipation,
it also can improve appetite, reduce depression, and improve self-esteem.
Furthermore, exercise has the benefit of slowing bone loss in women
with postmenopausal osteoporosis.52 Emphasis on
attainable goals rather than on pain symptoms during exercise results
in improved mood, less fatigue, increased capacity in most functional
tasks, and less perception of pain.53 Understandably,
the exercise program should be adapted to each person’s
ability and safety. Compliance is improved if low-tech, inexpensive,
and simple exercises are emphasized, group socialization is provided,
and personal exercise equipment is available such as stationary
cycles and free weights. Guidelines for exercise prescriptions are
shown in Figure 57-4.
++
++
Physical modalities should be employed in the treatment of musculoskeletal
or soft tissue pain. Examples include use of heat, cold, and manipulation
and massage. Because heat and ice can be self-applied, they give
patients some control over their symptoms and treatments. However,
precautions must be taken to avoid thermal burns.
++
Another effective behavioral intervention for those with cognitive
impairment is distraction. Examples of distraction techniques include
music, conversation, and activity involvement. Ensuring adequate
nutrition and sleep will also help make the pain more bearable,
and perhaps actually less intense as a sensory experience.