Talwin

Learn how to distinguish the types and causes to help your patient manage his pain.

When your patient has cancer, his disease and therapy can complicate pain management. In this article, we'll discuss what causes cancer pain, who's at greatest risk, and what assessment and treatment techniques you can use to help your patient control pain.

Multiple sources

Various factors can contribute to cancer pain, including tumor growth, therapies and procedures, infection, and vascular problems. Pain control gets more complicated if the patient is very young or very old, has trouble communicating, or comes from a different culture.

To get a handle on his symptoms, first consider the differences between nociceptive and neuropathic pain.

* Nociceptive pain, which results from stimuli to the tissues, may be somatic or visceral.

Somatic pain, arising in bone, joint, muscle, skin, or connective tissue, is well localized and constant. Your patient may describe it as aching, deep, dull, gnawing, throbbing, sharp, or stabbing. You can treat somatic pain with acetaminophen, nonsteroidal anti-- inflammatory drugs (NSAIDs), opioids, or a combination of these medications.

Visceral pain arises in organs enclosed within a body cavity, especially the abdomen. Tumor involvement or obstruction of a hollow viscus, such as the gallbladder duct, can cause intermittent cramping and poorly localized pain, squeezing, or pressure. Sometimes referred to distant sites, visceral pain can be treated with acetaminophen and opioids.

* Neuropathic pain occurs intermittently when the peripheral or central nervous system abnormally processes sensory input. Your patient may describe it as burning, numbness, radiating, shooting, stabbing, tingling, or sensitive to touch. Neuropathic pain is treated with NSAIDs, opioids (response may be poor), and coanalgesic medications, such as antidepressants or anticonvulsants.

Nociceptive and neuropathic pain can affect your patient simultaneously, and either type can be acute or chronic. Acute pain is new and alerts you that something's wrong. Chronic pain is ongoing and has many negative effects, including depression and decreased level of function.

Assessing your paties pain

The character and location of cancer pain can change frequently, so perform regular and thorough pain assessments and determine the intensity, quality, and locations. Take a pain history, remembering that pain is subjective, so the patients description is the best indicator of pain presence and intensity.

Ask him to rate his pain intensity on a standard pain rating scale, such as one ranging from 0 (no pain) to 10 (worst pain imaginable), and ask what he considers an acceptable level. Document his report.

He may have several pains at one time, so pinpointing locations is important. To determine how his pain affects him, ask what makes it better or worse and how well he's sleeping. Find out how well his current medications reduce pain, how often he needs doses for breakthrough pain, and whether he's having adverse reactions. Encourage him to keep a pain log or diary.

If your patient is comatose, confused, or demented, assume that he's in pain and begin your pain management plan. If he speaks a language you don't understand, get an interpreter.

Opioids, a key player

Opioids are the mainstay of treatment for moderate to severe cancer pain. Morphine, oxycodone, and fentanyl should be titrated to comfort. Coanalgesics, such as antidepressants, NSAIDs, and anticonvulsants, are used to enhance opioids' analgesic effects, to treat concurrent symptoms that worsen pain, and to provide analgesia for specific types of pain. Using coanalgesics may let you give lower opioid doses and so reduce adverse reactions.

The American Pain Society and the World Health Organization (WHO) offer these general guidelines for treating pain.

* Follow the WHO three-step analgesic ladder to better manage your patients pain. For mild pain, the WHO recommends nonopioids; for mild to moderate pain, nonopioids plus opioids; and for moderate to severe pain, nonopioids plus strong opioids. Coanalgesic medications should be considered for all types according to the patients clinical condition. (See Coanalgesics for Cancer Pain to learn the options.)

* Individualize the route, dosage, and schedule. Titrate opioid dosing to achieve maximum analgesia with minimal adverse reactions. For example, an elderly patient may need longer dosing intervals because of decreased absorption, distribution, metabolism, and elimination; a child's requirements can be unpredictable and must be individualized.

Encourage your patient to verbalize his pain needs, and emphasize that he has a right to pain relief. Frequently assess his pain and his responses to medication and make sure that doses and intervals are adjusted to meet pain management goals.

* Administer analgesics around the clock if your patient has pain most of the time. Anyone taking opioids around the clock for moderate to severe pain should also have access to rescue analgesia for breakthrough pain.

* Become familiar with every analgesic you administer, including the usual dosage, route, onset and peak times, and duration.

* Continually assess your patient for pain. Monitor pain intensity and his response to analgesia, especially when initiating, titrating, or changing opioids or when converting to controlled-release preparations. Use equianalgesic dose charts to make sure he gets adequate pain relief when switching from one analgesic to another.

* Anticipate, prevent, recognize, and manage adverse reactions. When your patient begins taking analgesics, initiate a bowel regimen to combat constipation. If he's taking opioids, he won't develop tolerance to this problem so he'll need prophylactic laxatives containing a stimulant and a stool softener.

If your patient is starting an opioid or his dose increases, reassure him that sedation is common and his body should adapt within a week or so. Adverse reactions to opioids are usually dose related, and opioid-naive patients have the greatest risk of respiratory depression. Monitor your patients respiratory status and sedation level because sedation precedes respiratory depression. Use a standard sedation scale if he's opioid-naive.

* Avoid administering certain medications or excessive amounts to treat chronic pain. Normeperidine, the active metabolite of meperidine (Demerol), has neurotoxic effects and could trigger potentially lifethreatening seizures. Pentazocine (Talwin), a mixed agonist-antagonist, can trigger hallucinations. Excessive acetaminophen (recommended daily maximum dose, 4 grams) can cause fatal liver damage; teach your patient to read all prescription and overthe-counter drug labels and not to exceed this amount.

* Administer opioids by the least invasive route. The oral route is preferred. Avoid intramuscular injections because absorption is unreliable and can cause pain, sterile abscesses, or tissue fibrosis. A few patients may require epidural or intrathecal therapy.

* Watch for the development of opioid tolerance and respond appropriately. Your patient may need a dosage increase to maintain the analgesic effect. Remember, the ability of opioids to relieve pain has no ceiling.

* Be aware of the development of physical dependence on opioids and prevent withdrawal. A patient who's taken opioids around the clock for weeks will experience withdrawal if he stops abruptly If he no longer needs an opioid, titrate the dose down in a slow, continuous manner.

* Don't consider a patient addicted because he's developed physical dependence or tolerance to opioids. Research shows that using opioids for pain relief almost never causes addiction, which is characterized by psychological dependence and compulsive use for reasons other than pain relief. (See Don't Call It Addiction.)

* Be alert to the patients psychological state. Unrelieved pain increases his risk of depression and anxiety. Perform a thorough assessment of his psychological and social state, including his beliefs about pain.

More than medication

Although careful assessment and medication therapy are key to managing your patients cancer pain, you can do much more to enhance his comfort and the success of his therapy. For example, use nonpharmacologic techniques such as distraction, imagery, relaxation, heat and cold applications, massage, or prayer to help keep him comfortable. Make sure he gets enough rest and maintain his nutritional status as appropriate.

When you call a practitioner about your patients pain, have these facts on hand: his numeric pain score, sedation level, total doses of all analgesics he's received in the last 24 hours, presence of unwanted effects, his functional level, and how he and his family perceive his pain relief.

Evaluate your patient's analgesic use and develop a pain relief recommendation. Suggest an appropriate dose of pain medication and be prepared to explain how you made dose conversions.

Document your patients response to all analgesic changes so other health care providers know about and understand the effectiveness of pain management interventions. If his pain isn't controlled, consult a pain management specialist.

Dealing with the variables

By recognizing the sources and types of cancer pain, you can confront the variables and help your patient with cancer better manage his pain.

Don't call it addiction

A patient may develop physical tolerance and dependence with chronic opioid use for pain relief, but he's unlikely to become addicted. Here are the differences:

* Physical tolerance is a common physiologic response to chronic opioid use that calls for larger doses to maintain the same level of analgesia.

* Physical dependence is the body's physiologic adaptation to opioids. Rapidly decreasing or suddenly stopping opioid use would cause the patient to develop opioid abstinence syndrome (withdrawal), characterized by anxiety, irritability, chills and hot flashes, joint pain, lacrimation, rhinorrhea, diaphoresis, nausea and vomiting, and abdominal cramps and diarrhea.

* Addiction is a psychological dependence. It's a pattern of compulsive drug use characterized by continued craving for opioids and the need to use them for effects other than pain relief,

SELECTED WEB SITES

American Pain Foundation: http://www.painfoundation.org

American Pain Society: http://www.ampainsoc.org

The Mayday Pain Project: http://www.painandhealth.org Last accessed on March 5, 2003.

SELECTED REFERENCES

American Pain Society: Principles of Analgesic Use in the Treatment of Acute Pain and Cancer Pain, 4th edition. Glenview, Ill., American Pain Society, 1999.

McCaffery, M., and Pasero, C.: Pain: Clinical Manual, 2nd edition. St. Louis, Mo., Mosby, Inc., 1999.

Meyer, R.: "Measuring Quality of Care at the End of Life: Who? When? Where? and How?" Western Journal of Medicine. 172(6):377-378, June 2000.

Smith, T., et al.: "Randomized Clinical Trial of an Implantable Drug Delivery System Compared with Comprehensive Medical Management for Refractory Cancer Pain: Impact on Pain, Drug-related Toxicity, and Survival," Journal of Clinical Oncology. 20(19):4040-4049, October 1, 2002.

Ashby C. Watson is a psychosocial oncology clinical nurse specialist and Patrick 1. Coyne is a clinical nurse specialist for palliative care and pain management at the Virginia Commonwealth University Health System in Richmond, Va.

Copyright Springhouse Corporation Apr 2003
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