Trial Comparing Morphine to Hydromorphone in Elderly Patients With Severe Pain

• The between-group difference in before-after improvement in pain scores measured 30 minutes after medications are infused.
  

• Pain score comparisons at 15 minutes and 120 minutes
  
• Total mg of additional pain medications required after initial medication
  
• Pain relief measurement
  
• Patient satisfaction measurement
  
• Comparison of adverse events
  

Pain is cited as the most frequent reason for visit to emergency departments (EDs) (McCaig, 2001). It can be estimated from the National Hospital Ambulatory Medical Care Survey, an annual survey of a representative sample of visits to US EDs, that there are 17 million visits per year to US EDs for specific complaints of pain, 29 million visits including “back symptoms” and “injuries not otherwise specified” as well as specific mentions of pain. However it is widely acknowledged that pain is seriously under-treated in the ED as well as in other health care settings (Ducharme, 1996; Selbst, 1990; Wilson, 1989). The concern regarding under-treatment is reflected in new standards for pain management developed by the Joint Commission on Accreditation of Healthcare Organizations (JCAHO) requiring assessment of pain at triage in the ED and referring to pain measurement as the “fifth vital sign” (Philips, 2000).

Proper pain management is a tremendous challenge to ED physicians as pain is not only a noxious experience but also a symptom of injury and disease that needs to be understood and appropriately treated. Further complicating pain management is the large interpersonal variability in pain perception and expression reflecting cultural, contextual, and individual differences between people. Reasons for under-treating pain include concern over side effects of opioids, perception of pain complaints as possible drug-seeking behavior, under-staffing, concern that analgesics will mask symptoms, delay early diagnosis, treatment, and contribute to risks of tolerance and dependence in vulnerable patients.

The elderly represent a group of patients who may experience pain differently from the non-elderly patient (Li 2001, Collins 1966, Walsh 1989, Woodrow 1972). This growing population has been significantly underrepresented in pain-related studies. Some studies have shown that the elderly are at risk for “oligoanalgesia” and receive inadequate doses of pain medication (Jones 1996).

Morphine has long been considered the gold standard in pain control. Hydromorphone is another powerful opiate that has been used extensively for the management of post-operative pain and morphine-resistant cancer-related pain. A recent Cochrane review on the use of hydromorphone found 32 studies that focused on acute pain (Quigley, 2003). Of these 32 studies, only 9 involved intravenous forms of hydromorphone (Coda, 1997; Collins, 1996; Deutsch, 1968; Jasani, 1994; Liu, 1995; Mahler, 1975; Rapp, 1996; Searle, 1994; Urquhart, 1988). Of these 8 studies, 5 involved patient controlled analgesia, and only 1 study compared IV hydromorphone to IV morphine (Mahler, 1975). The Cochrane review concludes that there are gaps in the understanding of the efficacy and potency of hydromorphone. Only 1 study of hydromorphone in the ED could be located and this compared IV hydromorphone versus IV meperidine in patients with ureteral colic (Jasani, 1994). Although this study showed hydromorphone was superior at all time periods and had fewer side effects, the study used fixed doses of hydromorphone (1mg) and meperidine (50mg).

It has been the clinical experience of some ED physicians that hydromorphone may be a better opiate in patients presenting to the ED with acute pain. Hydromorphone is also the opiate that is usually given if morphine does not adequately control a patient’s pain in the ED.

Hydromorphone may also have other benefits, such as a faster onset since it is more lipophilic than morphine and crosses the blood-brain barrier faster.

If it is shown that hydromorphone gives better pain relief to patients with comparable or fewer side effects when compared with morphine, then we may be able to provide evidence to suggest that hydromorphone should be the parenteral opiate of choice for adult ED patients presenting with acute pain of moderate to severe intensity.