- Types of Pain
- Nonpharmacologic management
- Pharmacologic management
- Opioid side effects
- Pharmacologic Dosing and titration tips
- Pain and chemical dependency
- Pain management myths
“Pain is whatever the experiencing person says it is, existing whenever he says it does”. (McCaffery, 1968, p. 95)
Pain is a subjective finding. It is common in advanced diseases, such as metastatic cancer, multiple sclerosis, cardiac disease, and diabetes mellitus, as well as chronic illnesses such as osteoarthritis. Understanding the different types of pain, the common words used to describe pain, and common diseases that can cause pain can help clinicians with decisions about what treatments will be most helpful.
Acute pain has an identifiable cause, usually an injury such as a fracture, bruise or other type of tissue injury, and it decreases in intensity as healing occurs. Unless there are other issues present, such as a recent diagnosis with a life-limiting illness or other symptoms that make the management more complex, this type of pain can ideally be managed by the generalist provider.
Chronic pain persists for about three months after the initial injury has healed. It can be complicated by behavioral component such as depression and/or anxiety as the person adapts to the pain experience. A pain management specialist may be indicated for those persons with nonmalignant chronic pain, especially if there is concern about potential substance abuse. A palliative care specialist may be appropriate for those with chronic pain related to a serious illness, such as pain related to a malignancy.
Pain pathophysiology can be broken into two distinct types: nociceptive - pain that occurs as a result of tissue injury and neuropathic - pain that occurs as a result of nerve injury.
There is a variety of non-pharmacologic methods that can be used alone or in conjunction with medication depending on the severity and type of pain.
- Hot and/or cold packs
- Music therapy
- Physical therapy/occupational therapy
- Relaxation techniques
In 1986, the World Health Organization (WHO) published a stepped approach to the management of cancer-related pain. Since that time, the WHO ladder has been used to guide the treatment of all types of pain including nonmalignant pains such as osteoarthritis pain, chronic back pain, and others. While experts in pain management and in palliative care differ on their opinions of how closely prescribers should adhere to the stepped approach, the ladder does offer a helpful framework for thinking about managing pain. In general, the type of medication should be consistent with the type and severity of pain. Consult an evidence-based guideline for further information in the palliative treatment of pain.
- WHO Ladder (PDF)
- Non-opioid analgesics such as acetaminophen and non-steroidal anti-inflammatory medications (NSAIDs) such as ibuprofen have what is known as a ceiling effect. Increasing doses of these medications beyond a certain point does not provide any greater analgesic effect and in fact, creates the potential for increasing harmful side effects. For example, a healthy adult can take up to 4 grams of acetaminophen in a day for pain relief. Doses greater than 4 grams put the adult at increased risk of liver damage without contributing any greater analgesic effect. NSAIDs, at doses greater than a 1000 mg ibuprofen equivalent, are also unlikely to produce any additional pain relief, while increasing the risk of unwanted effects on the stomach, intestines, and kidneys. Opioid analgesics do not have a ceiling effect. Doses can be increased to the level required for pain relief without increasing the side effect risk. NSAIDS are contraindicated in persons with known gastrointestinal bleeds, heart failure, or chronic renal dysfunction.
Here are the most commonly experienced side effects related to opiate use. Some people may confuse these side effects with an allergic reaction. For instance, the patient that experiences nausea due to opiate use may think this is an allergic reaction. If a patient states they are unable to take opiates due to allergies, careful questioning about the “allergic reactions” is generally warranted.
- Sedation occurs in 20–60% of patients at the initiation of opiate therapy and at the time of dosing increases. Mild to moderate sedation usually dissipates after a few days; however, moderate to severe sedation may be an indication for tapering the opioid dose. If sedation persists and pain is managed, a reduction in dose may be warranted. If pain is not well managed, a referral to a palliative care specialist may be needed.
- Decreased Respiratory Drive is a life-threatening situation and must be addressed immediately. Severe sedation always occurs before any decrease in the respiratory drive and may be an indication for opioid tapering. For the person who is not at the end of life, a significant decrease in respirations (below 10 respirations/minute) warrants airway support and judicious use of naloxone. For the person with serious illness at the end of life, a careful review of goals of care must be taken into account. Decreased respirations and/or irregular breathing may be an indication that the dying process has begun and therefore any change in medication may increase suffering. Referral to a palliative care specialist or hospice is appropriate.
- Nausea/vomiting occur in 10–40% of patients and usually dissipates after 5–7 days. Though not usually used prophylactically, antiemetics such as prochlorperazine or ondansetron can be used for treatment. If nausea persists, an assessment of other causes than opioid initiation is required.
- Pruritus only occurs in 2-10% of patients and most commonly with epidural or intrathecal morphine. Pruritus can be treated with less sedating antihistamines such as hydroxyzine or with cool compresses/moisturizers. . A low-dose naloxone infusion may also be useful for reducing pruritus when opioid infusions are administered. If pruritus persists, a referral to a palliative care specialist for opioid rotation may be needed.
- Constipation also known as “Opioid Induced Constipation”, or O.I.C., does not dissipate over time and therefore requires consideration of a bowel regimen prescribed at the initiation and throughout the course of opiate therapy. If titration of the opiate is required to manage pain, the bowel regimen may also need to be adjusted. Constipation can be managed with a variety of stool softeners and laxatives. See Constipation for further information.
- Always use the oral route if possible.
- Never start an opiate-naïve patient (someone who has never taken an opiate analgesic before) on a long-acting opiate such as OxyContin or Fentanyl patches. You must first start with a short acting medication to assess response and approximate long-acting dosing requirements.
- Pain that occurs around the clock requires around-the-clock dosing.
- Anticipate side effects of opiates and educate patients and their families to be prepared. This is especially important with regard to opiates and constipation. Most specialist providers start a bowel regimen concurrent with an opiate.
- Non-pharmacologic approaches should always be considered in addition to pharmacologic management as they may help to reduce dosing requirements.
- Use nonsteroidal anti-inflammatory (NSAIDs) with extreme caution in patients over the age of 70 and those with a history of renal dysfunction, heart disease, and/or GI bleeds.
- Tolerance is defined by the need for increasing doses of a medication, such as an opiate, in order to maintain analgesic effect. This is not to be confused with addiction or with physical dependence. Other reasons for dosing increase may include disease progression, change in pain mechanism, such as nociceptive to neuropathic, or psychic pain.
- Physical dependence is defined by abstinence syndrome following abrupt dose reduction of different types of medications including opioids. Physical dependence is assumed to occur after dosing for several days, and therefore if medication is to be discontinued, it should be tapered in order to avoid withdrawal symptoms.
- Pseudoaddiction is defined by addiction-like behaviors that are driven by unrelieved pain. Behaviors stop once pain is relieved.
- Addiction is defined by maladaptive behaviors characterized by one or more of the following: impaired control over drug use, compulsive use, continued use despite harm, or craving.
Patients and families often have misconceptions about pain management.
- Pain can mean that their illness is worsening—this may or may not be the case.
- Good patients don’t complain – this is an especially common belief among in the elderly.
- Reporting pain may distract a provider from focusing on treatment of an illness—in reality, pain can be an important way for providers to understand the impact of an illness.
- Patients and families fear becoming addicted to opiates. This is an unlikely occurrence for those that may never have displayed addictive behaviors in the past. Nonetheless, providers must be vigilant with regard to the potential for addiction.
- They fear opioid side effects—but the truth is that most side effects can be managed proactively by prescribers. Education about the risks and benefits of pain management using opiates can be helpful especially if the goal of treatment is improved quality of life.
Providers also have misconceptions.
- The feeling that a patient’s self-report of pain is not valid, that their assessment of the person before them is a better indication of the pain experience. Remember that pain is a subjective finding and therefore based on patient report, not provider assessment.
- Addiction to pain medication is common – it is not common.
- Concerns that respiratory depression is a common complication of opioid use— but respiratory depression is rarely a risk except perhaps in the opioid-naïve person. Slow and careful titration of opiates by a skilled provider obviates this risk.
Clinical Practice Guidelines
- Clinical Guidelines for the Use of Chronic Opioid Therapy in Chronic Non Cancer Pain
- American Pain Society Clinical Practice Guidelines
- US Department of Veterans Affairs Clinical Practice Guidelines
- Institute for Clinical Systems Improvement
- Opioids In Palliative Care: Safe And Effective Prescribing Of Strong Opioids For Pain In Palliative Care Of Adults (AHRQ guideline)
- Acute Pain Assessment And Opioid Prescribing Protocol
- Pharmacologic Management of Persistent Pain in Older Persons (AGS guideline)
- Fast Facts
- Fraser Health
- National Comprehensive Cancer Network (requires free registration)
- Evidence-Based Interventions to Improve the Palliative Care of Pain, Dyspnea, and Depression at the End of Life: A Clinical Practice Guideline from the American College of Physicians
- Fine, P. G., and Portenoy, R. K. (2004). A Clinical Guide to Opioid Analgesia. Minneapolis: McGraw-Hill.
- Kuebler, K. K., Heidrich, D. E., and Esper, P. Palliative and End-of-Life Care: Clinical Practice Guidelines (St. Louis, MO: Saunders, 2007).
- McCaffery, M., and Pasero, C. Pain Clinical Manual, 2nd Ed. (St. Louis, MO: Mosby, 1999).
- McCaffery, M. Nursing Practice Theories related to Cognition, Bodily Pain, and Man-Environment Interactions (Los Angeles, California: UCLA Student Store, 1968).
- 8. Thomas, J. “Optimizing Opioid Management in Palliative Care.” Journal of Palliative Medicine; 10 Suppl 1:S1-18; quiz S19-23 (2007): doi: 10.1089/jpm.2007.9828.
- Wrede-Seaman, L., Symptom Management Algorithms: A Handbook for Palliative Care, 3rd ed. (Yakima, Washington: Intellicard, Inc, 2009).
- 10. Roth, S. H., and Fuller, P. “Diclofenac Topical Solution Compared with Oral Diclofenac: A Pooled Safety Analysis.” Journal of Pain Research 4 (2001): 159-167. doi: 10.2147/JPR.S20965.
Helpful Web Sites
- Partners Against Pain
- The American Academy of Pain Medicine