About 25 million Americans experience acute pain from injuries or surgery, while an additional 50 million suffer chronic pain from musculoskeletal disorders, headaches, cancer, neuropathies, and other conditions. Common acute pain problems in primary care are low back pain (which can also be chronic), gastrointestinal (GI) pain, chest pain, headache, joint pain, and pain resulting from injuries. Some of the most common forms of chronic pain include back pain, headache, and joint pain (e.g., osteoarthritis).

In several recent surveys, about one fourth of adults in the United States reported that they recently had an episode of acute pain. For 20% of Americans, major lifestyle changes in employment, housing, personal freedom or mobility were necessary because of pain. In a panel study of 805 pain patients, over 40% said they could not complete a full day’s work while almost 60% said they had trouble concentrating. According to the National Institutes of Health, pain costs the American public more than $100 billion each year in health care, compensation, and litigation.

Yet many people are reluctant to seek treatment for pain. In a 2007 survey, only 16% of adults experiencing acute musculoskeletal pain said that they went to their primary care physician, and 70% did not seek any medical care at all because they didn’t feel the pain was sufficiently severe, thought it would resolve, or preferred to “tough it out.”

Even though pain treatment guidelines have been developed in the last decade, undertreatment of pain remains a problem. As a result, neo, or “new” thinking about approaches to pain management are being taken.

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Consequences of Unresolved Pain

Unrelieved acute pain often causes sensitization and remodeling of neurons that lead to the development of chronic pain. The cascade of events that leads from acute to chronic pain can begin within hours of injury. Acute pain results in a physiological response consisting of increased heart rate, blood pressure, and systemic vascular resistance; impaired immune function; altered release of pituitary, neuroendocrine, and other hormones. Studies of the transition from acute to chronic pain suggest that pain problems are more likely to become chronic in the presence of anxiety and distress, depressed mood, disability related to the pain, and a lack of belief that the pain will resolve. Therefore, unresolved acute pain may have serious long-term consequences.

A lack of systematic mechanisms for assessing and tracking pain contributes to its undertreatment. Many patient assessment tools do not include chart space for assessing pain, contributing to poor assessment, treatment, and global management of pain. And, while analgesics are the most commonly prescribed medicines for pain, they are often underutilized in the treatment of moderate to severe pain.

Barriers to Effective Pain Management

Many factors contribute to the undertreatment of pain, including patient and provider knowledge, attitudes, and behaviors and communication. Both patients and healthcare professionals have concerns that hinder optimal pain management. For patients, concern about side effects, the inability to communicate effectively about their pain experience, low expectations based on past pain and pain management experiences, and concern about addiction, tolerance, and physical dependence may be barriers to treatment. While the perception of addiction and misuse is high among patients receiving opioids, the reality is different. In a 3-year registry study of non-cancer patients requiring opioid analgesia for moderate to severe pain, only six cases (2.6%) of possible drug misuse were reported. GI and CNS side effects can be a barrier to effective pain management. In one study, when asked to make “tradeoffs” in pain management, most patients chose less pain relief instead of increased/or more severe nausea and vomiting side effects from pain medication.

For healthcare professionals, fear of regulatory scrutiny, patient drug-seeking behavior, opioid-related side effects, inconsistent use of pain assessment scales, and reluctance to accept patients’ self reports of pain contribute to ineffective pain management. For example, a recent physician survey found that 23.8% of respondents intentionally limit the amount of pain medication that they prescribe to avoid regulatory investigation. While many physicians are reluctant to prescribe controlled substances, the risks for both patient addiction and physician disciplinary action are much smaller than commonly believed. Of 4,169 disciplinary actions taken by state medical boards in 2002, only 2% (89) involved the prescribing of controlled substances. Better communication between patients, pharmacists, physicians, and other caregivers can help change the course of moderate to severe pain management.

Addiction, Tolerance, Physical Dependence

Understanding the difference between addiction, tolerance, and physical dependence and educating patients about it can help address patient concerns and avoid the consequences of undertreatment of pain.

New Pathways in Pain Management

The pathophysiology of pain may support a multipathway approach to analgesia. These multiple pathways of pain transmission provide multiple targets for pain relief.

The ascending pathway transmits pain impulses to higher levels in the CNS. The descending pathways enhance inhibition of pain signaling. The ascending pathways are inhibited by opioids, local anesthetics, antiepileptics, and NSAIDs/acetaminophen. The descending pathways are enhanced by norepinephrine reuptake inhibitors, serotonin reuptake inhibitors, tricyclic antidepressants, and opioids. A deeper understanding of CNS pathways and targets involved in pain offers expanded possibilities for efficient, comprehensive pain management.

Common Side Effects

For moderate to severe pain, opioids are the mainstay of treatment. Pure mu opioid agonists have doseproportional analgesic effects but those effects are constrained by dose-limiting side effects. Clinically important side effects often include those affecting the GI tract and CNS. The GI side effects include nausea, vomiting, and constipation. The CNS side effects include dizziness, sedation/somnolence, and headache. For some patients, the desire to avoid analgesic side effects can be more important than pain control. Educating patients about side effects and offering them ways to address side effects can be an important role for pharmacists in pain management.