Most pain is acute and short lived. Acute pain is primarily a symptom of a pathological process or injury. Typically treating the illness or injury will reduce or eliminate acute pain symptoms. Analgesic medications are often used in this setting for comfort during the healing process. For the most part, treatment of the underlying pathology or injury and medication management are effective in the treatment of acute pain. Many resources exist for assisting clinicians with acute pain management strategies.

Despite even the best efforts, acute pain evolves into chronic pain in approximately one out of five patients. The management of chronic pain is complex and often involves both pharmacological and nonpharmacological interventions. Because chronic pain is also modulated by psychological status (e.g., depression and anxiety), environmental consequences (e.g., stressors or reinforcers), and prior conditioning history, a comprehensive, multidisciplinary approach to management of this condition is of critical importance.

Management of patients with chronic pain is often challenging and can lead to complex patient–physician relationships. Often these relationships engender strong reactions from primary care providers. This chapter focuses on helpful strategies for the management of chronic pain and approaches for facing the particular challenges of caring for patients with chronic pain.

The International Association for the Study of Pain (IASP) defines pain as an “unpleasant sensory and emotional experience associated with actual or potential tissue damage.” The transition from acute to chronic pain is defined by duration. Acute pain may last up to 3 months at most, whereas chronic pain is any pain that lasts more than 3 months. Although pain from untreatable malignancies often lasts many months and is ­progressive, the terminal nature of the underlying condition leads most to consider cancer-related pain separately from chronic noncancer pain. Roughly 20% of the patients with acute pain will eventually seek treatment each year for chronic noncancer pain. Of these, 62% will report having pain for longer than 1 year; 57% report that their pain is episodic (e.g., migraine, neuropathy), whereas 43% will report having constant pain.

Chronic noncancer pain accounts for more than 70 million office visits per year in the United States, with annual direct medical costs of $125 billion. The cost of treating low back pain alone averages almost $86 billion annually. Although the diagnosis of low back pain represents only 5–10% of all disability claims, these claims account for 80–85% of the costs of disability.

Taking care of patients with chronic noncancer pain can be problematic for the primary care provider. Even the most experienced practitioners occasionally find the clinical relationship with a patient with chronic pain to be challenging and frustrating. Some patients with chronic pain are engaged in living active lives with modest and stable doses of medication. Others are inactive and passive, seeking to rely only on escalating doses of medication, and often put their lives on hold as a result of pain. Primary care providers can find themselves in an oppositional relationship with the latter group of patients, which can lead to feelings of inadequacy, frustration, and anger for both the clinician and the patient.

Chronic pain typically has no cure and is poorly managed by medications alone. Although the etiology of chronic pain varies with each patient, there are usually comorbid psychological, social, and functional variables that contribute to the difficulty of managing patients with chronic pain. These comorbid conditions often need clinical attention as well. Treatment strategies limited to pharmacological interventions usually fail.

The effectiveness of the physician–patient relationship is defined largely by the physician’s ability to acknowledge the patient’s problem, address the patient’s goals, and establish a collaborative management strategy on which both the physician and the patient can agree. Because the primary concerns of the physician and the patient can be different, there is marked potential for miscommunication. An important first step for clinicians is to seek patients’ expectations of treatment before sharing their own approach and philosophy of chronic pain treatment. Establishing a clear clinician–patient relationship is central to successful management of chronic noncancer pain.

Patients dealing with chronic pain present for medical attention with a number of possible feelings and goals:

1. 
   

   They may simply want to discover the cause of the pain to allay fears about an underlying serious ­disease.

   
   
2. 
   

   They may be interested only in relief from the pain.

   
   
3. 
   

   They may want to regain impaired function to return to normal work, social, or recreational activities.

   
   
4. 
   

   They may want medical and social acknowledgment that the pain is preventing normal activities.

The “three-function model of the medical interview” (Table 35-1) can be utilized as a format for the ongoing evaluation and reevaluation of patients with chronic pain (see Chapter 1).

Pain management is based on a number of basic guidelines.

1. 
   

   Obtain a description of the pain and the meaning or impact the pain has on the patient’s life and the life of others around the patient.

   
   
2. 
   

   Assess for comorbid psychiatric conditions such as depression and anxiety.

   
   
3. 
   

   Perform a focused physical examination based on pain history.

   
   
4. 
   

   Review or obtain diagnostic studies that might rule in treatable physical pathology.

   
   
5. 
   

   Use communication and empathy skills to discuss pain treatment.

   
   
   
   
   1. 
      

      Explain rationale for nonuse of opioid analgesics for chronic noncancer pain.

      
      
   2. 
      

      Provide nonpharmacological alternatives in context of “stages of change” model.

      
      
   3. 
      

      Negotiate goals of treatment as restoring function and quality of life versus only eliminating nociception.

   
   
6. 
   

   Provide relief and comfort through medication and reassurance.

   
   
7. 
   

   Use multiple management modalities.

   
   
8. 
   

   Assess for change in pain behavior and overall ­function.

   
   
9. 
   

   Reinforce improvement in function and reduced pain (the goals of treatment) and discontinue ineffective treatments that do not achieve these goals.

The use of a “pain contract,” which defines conditions for prescription of opioid medications, is also helpful in the management of patients with chronic noncancer pain. The contract aims to thoughtfully establish the goals of management prior to the initiation of any therapy. Key elements of a chronic pain management contract are included in Table 35-2. Both the physician and patient should sign the contract prior to therapy initiation and both individuals should retain a copy. Violation of the contract by the patient can be met initially with a single written warning, but any ­subsequent violation should be met with the cessation of opioid therapy, after a brief taper to avoid opioid withdrawal. It is critical to make clear to the patient that care with other management strategies and interventions can continue even if opioids will no longer be ­prescribed.

Pharmacotherapy is often the first technique employed by the primary care provider for the management of chronic noncancer pain. It is an important technique in the treatment of pain, but should not be the mainstay of treatment. For mild-to-moderate pain, acetaminophen, aspirin, and nonsteroidal anti-inflammatory drugs (NSAIDs) may be sufficient. For moderate-to-severe pain, these agents combined with opioids may be helpful. Severe pain may require full opioid agonists.

Acetaminophen & NSAIDs

Acetaminophen and NSAIDs are in many cases the first-line pharmacotherapy for chronic noncancer pain. Appropriate doses of acetaminophen may be just as effective an analgesic and antipyretic as NSAIDs, but without the risk of gastrointestinal bleeding or ulceration. Hepatotoxicity is of particular concern because of how commonly acetaminophen is also an ingredient in various over-the-counter medications. Total acetaminophen doses should not exceed 3–4 g/day long term or 2 g/day for older patients and for those with liver disease.

Aspirin is an effective analgesic, antipyretic, and anti-inflammatory medication. Gastrointestinal irritation and bleeding are side effects, which are lessened with enteric-coated formulations of aspirin and concomitant use of proton pump inhibitor medication. Bleeding from other sources, allergy, and an association with Reye syndrome in children and teenagers further limit its use.

Commonly used NSAIDs and their dosages are listed in Table 35-3. Like aspirin, the NSAIDs are antipyretic, analgesic, and anti-inflammatory. NSAIDs increase the risk of gastrointestinal bleeding by 1.5 times normal. The risks of bleeding and nephrotoxicity from NSAIDs are both increased in elders. Topical formulations of diclofenac (patch or gel) result in lower blood levels of the NSAID and may be associated with decreased systemic side effects. NSAID gastrointestinal bleeding and ulceration may be prevented with the concurrent use of proton pump inhibitors or with the class of NSAIDs that inhibit only cyclooxygenase (COX)-2. Celecoxib is the only COX-2 inhibitor available and should be used with caution in patients with cardiac disease. The NSAIDs, including COX-2 inhibitors, can lead to fluid retention and exacerbations of congestive heart failure and should be used with caution in patients with that condition.

Opioid Medications

Opioid therapy has its place in the management of chronic noncancer pain, yet it is important to note that opioids alone will rarely be sufficient to adequately manage the pain and in this clinical setting should be used in conjunction with the other management strategies outlined in this chapter. Certainly, however, this class of agents is effective for pain management and should be used in select patients with chronic persistent or debilitating pain that is not well controlled with nonopioid treatment strategies. In certain populations, particularly chronic low back pain, consideration should be given to limiting or reducing opioids over time as other modalities are likely to be more effective.