Pain, one of the most common reasons patients present to the ED, may be a primary complaint or a warning sign encouraging further evaluation. The decision to treat pain is one of the most frequent therapeutic decisions made by emergency physicians (EPs) and involves a variety of options and considerations. Moreover, the decision of how to treat pain similarly encompasses a wide selection of variables, including etiology and severity of the pain; intravenous (IV) access; medication allergies; renal function; alcohol use; rapidity of onset; patients’ vital signs; patient preference; and mode of transport upon discharge. Given all of these considerations, there is no perfect analgesic to suit every circumstance. Rather, EPs must tailor their analgesic selection to the individual clinical situation and patient.
The literature over the past 20 years is replete with studies demonstrating the undertreatment or inadequate treatment of pain in the ED.1-5 Often referred to as oligoanalgesia,6 contributing factors include physician concerns regarding adverse side effects, secondary gain, and drug addiction. In addition, the increasing pressure placed on EPs to diagnose and dispose patients quickly likely relegates pain control to a secondary concern.
Further complicating the issue, physicians’ own prejudices and perceptions appear to influence their analgesic prescription practice. For example, several studies have demonstrated that black patients do not receive prescriptions for analgesics similar to those written for white patients in general, and particularly not for opioid analgesics. In a meta-analysis of pain treatment disparity studies, blacks were 22% less likely than whites to receive any analgesics, and 29% less likely than whites to receive opioid treatment for the same type of painful conditions.7 Likewise, Hispanic/Latino patients were also 22% less likely than their white counterparts to receive opioid treatment for similar pain.7 Physicians must keep these common biases in mind when treating patients for pain.
The administration of analgesics and the prescription habits of physicians has never been under greater scrutiny. The Centers for Medicare and Medicaid Services has benchmarked “median time to pain management for long bone fractures” as a core measure, possibly affecting hospital reimbursement rates. Similarly, every patient satisfaction survey specifically inquires about the timeliness and adequacy of pain control. At the same time, though, the increasing problem of prescription opioid abuse has become the nation’s fastest growing drug problem. In 2013, prescription drug abuse was second only to marijuana as the most abused drug category.8 Contributing to this problem are the frequency and ease with which many physicians prescribe opioids. From 1997 to 2007, the milligram-per-person use of prescription opioids in the United States increased from 74 mg per year to 369 mg per year—an increase of 402%.9 As a result, some legislators are now calling for mandatory educational sessions for any physician prescribing medications containing opioids.
Though there are many classes of medications used to treat pain, and numerous individual drugs within each class, this article focuses on several of the more commonly prescribed medications in the ED, including their mechanisms of action, advantages, and disadvantages. The management of pediatric pain and procedural sedation and analgesia are not discussed in this review, as each of these topics deserves a separate detailed discussion.
Recognizing and Quantifying Pain
The first step in treating pain appropriately is recognition. Physicians must specifically inquire about pain and not rely solely on a patient’s unprompted complaint. Several pain scales exist, including the Faces Pain Scale (ie, pictorial representation of a smiling face on one end indicating “no pain” to a frowning face on the opposite end); the verbal quantitative scale or numerical rating scale (ie, “how would you rate your pain on a scale of 0 to 10, with 10 the worst pain ever?”); and the visual analog scale (ie, a 10-cm linear scale marked at one end with “no pain” and “worst pain imaginable” at the opposite end).10,11 Probably the most commonly used scale in the ED is some variation of the numerical rating scale (NRS).1
Each of these scales has its own advantages and disadvantages, but the important point is that patients are given the opportunity to express the type and degree of pain to the healthcare provider. In addition, a pain scale provides a starting point against which the practitioner (or later practitioners) can determine the success (or failure) of a pain treatment strategy.
Three-Step Ladder
In 1996, the World Health Organization developed a three-step analgesic ladder to guide the management of cancer pain.12 Its use has been expanded over time to include treating pain of noncancer etiology. Mild pain (NRS of 1 to 3) is considered Step 1; moderate pain (NRS 4 to 6) is considered Step 2; and severe pain (NRS 7 to 10) is Step 3. For Step 1 (mild pain), acetaminophen or a nonsteroidal anti-inflammatory drug (NSAID) is recommended. For Step 2 (moderate pain), a weak opioid (ie, codeine or hydrocodone) with or without acetaminophen or an NSAID is recommended. Finally, for Step 3 (severe pain), a strong opioid such as morphine or hydromorphone is recommended.