Having assessed the patient's pain, a strategy for management should be developed. The discussion that follows emphasizes opioids because these are so commonly used in palliative care. However, this is not to suggest that opioids are more or less appropriate in any individual case. Sound clinical judgment must be used in selecting specific agents.
Although the emphasis here is on the pharmacology of pain management, the clinician should also consider other interventions in developing a strategy. How does the patient's psychological state affect his or her pain? Is the patient depressed, anxious, or confused? How does the patient relate to his or her pain? Some patients want all pain to be abolished. Others may want some pain to remain. (As one cancer patient put it, "If I didn't feel some pain, how would I know what that cancer is doing in there.") Some may see the pain as something to be conquered. Some may see it as something to be accepted. A thorough discussion of the psychological and spiritual aspects of pain is beyond the scope of this text. Often, assistance from others - psychologists, psychiatrists, social workers, and chaplains - will be necessary if proper care is to be delivered.
A variety of medical interventions other than medications may also be extremely useful. Radiation therapy and chemotherapy may help alleviate pain in patients with certain cancers. Nerve blocks, trigger-point injections, and (rarely) surgical approaches may also be useful. Physical therapy, occupational therapy, and massage therapy may help in certain cases. Experts in these areas should be consulted, as needed.
1. Avoid specific toxicities. In choosing among possible medications, an otherwise useful drug might be excessively toxic for a particular patient. A patient with thrombocytopenia, for example, would be a poor candidate for a traditional nonsteroidal anti-inflammatory drug (NSAID), because such drugs interfere with platelet aggregation.
2. Look for "two-fers." When possible, identify agents with additional effects that might be beneficial - two for the price of one. Anticonvulsants, for example, might be particularly useful in a patient with a seizure disorder who also had neuropathic pain. In contrast, one might choose a tricyclic antidepressant (TCA) for neuropathic pain in a depressed patient.
3. Think about who will be administering the medicine. A medication that requires injection might be very appropriate in a hospital or nursing home but difficult to administer at home. Competent patients administering their own medications may be better able to manage short-acting pain medications on an as-needed basis. In contrast, a demented patient with pain cared for in a nursing home or at home by family will probably receive inadequate analgesia when treated q4 h prn, as family and staff may not assess pain regularly (especially at night) and the patient may be unable to advocate for him- or herself. Long-acting preparations of both NSAIDs and opioids may be more appropriate in such a situation.
4. Consider the drug delivery route of administration. Possible routes of therapy include oral, enteral tube, percutaneous and parenteral intravenous (IV), intramuscular (IM), and subcutaneous (SC). (See later discussion of routes of delivery)
5. Identify the patient's pain pattern and perform pattern matching with your therapy.
Management of pain is optimized when therapy overlaps the patient's pattern of pain. This maximizes analgesia while minimizing side effects. In using opioids for therapy when pain increases, so should the drug dose. Similarly, when pain lessens, the drug dose should be decreased. Pain itself can counteract certain opioid side effects. In particular, sedation and respiratory depression are significantly blocked by pain. Thus, the goal in using opioids is to have pain signals and opioid signals neutralize each other.
Acute pain, with a pattern of rapid escalation and de-escalation, requires short-acting opioids and careful titration if pain is to be adequately managed and side effects avoided (Fig. 4.1).
Figure 4.1. Acute pain pattern matching. Analgesia is maximized and side effects minimized when the rise and fall of the blood level of an analgesic closely overlaps the temporal pattern of a patient's pain.
Chronic pain typically has both a background "noise" of pain with intermittent spikes of incident, or breakthrough, pain. The general strategy for such pain is to use a long-acting agent to manage the background basal pain and short-acting opioid doses as needed for breakthrough pain (Fig. 4.2).
Figure 4.2. Chronic pain pattern. Generally, a long-acting medication for the baseline pain that is always present and a short-acting medication that rapidly peaks in tandem with an acute paint spike are needed.
While these are common patterns, the patient's individual pain pattern should be considered. For example, a patient may complain of pain only at night. This pattern should generate a "differential diagnosis" that may lead to important changes in therapy. This pattern may reflect pain worsened by lying down. Perhaps the patient is unable to get needed pain medications at night, as he or she is dependent on others, family, or nursing staff who may be less responsive during this time. Maybe he or she is no longer distracted, as in the daytime, which increases an awareness of pain. Each of these underlying causes would require a different approach. (Fig. 4.3)
Figure 4.3. Pain exacerbation at night. What is the "differential diagnosis" for this kind of pain?
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Palliative Care Perspectives
James L. Hallenbeck, M.D.
Copyright © 2003 by Oxford University Press, Inc.
The online version of this book is used with permission of the publisher and author on web sites affiliated with the Inter-Institutional Collaborating Network on End-of-life Care (IICN), sponsored by Growth House, Inc.