Safety and Efficacy of Intravenous Hydromorphone in Elderly Emergency Department Patients With Acute Severe Pain

Inclusion criteria

• Age greater than or equal to 65 years: This is a study of elderly patients.
• Pain with onset within 7 days: Pain within seven days is the definition of acute pain that has been used in Emergency Department (ED) literature.
• ED attending physician's judgment that patient's pain may warrant intravenous (IV) opioids: The factors that influence the decision to use parenteral opioids are complex and extensive. An approach that is commonly taken to address the issue of patient selection in drug trials is to use a specific condition (e.g., renal colic) or treatment (e.g., post-hysterectomy) that would generally be thought to be appropriately treated with an opioid analgesic, thereby eliminating individual judgment about eligibility for the study. However in order to assess the role of opioids with the widest generalizability in the ED setting, the investigators decided to enroll patients with a variety of diagnoses, all with a complaint of acute pain. Opioids are not an appropriate treatment for all patients who present with a complaint of pain (e.g., gastroenteritis, migraine). Therefore, unless there is a restriction to patients with a specific diagnosis, either a comprehensive list of diagnoses and situations in which opioids are indicated must be specified, or clinical judgment needs to be used. The investigators have opted for the latter alternative.
• Normal mental status: In order to provide measures of pain experienced the patient needs to have a normal mental status. The investigators will use a 6-item screener (Wilber 2008) as an indicator of sufficiently normal mental status to participate in the study.

Exclusion criteria

• Prior use of methadone: the effect of methadone use on the perception of acute pain is unknown and suspected to be altered. The investigators feel that the needs of patients on methadone may exceed the dosage ceiling of 1 mg that will be used for this study. Similar to sickle cell patients and chronic cancer patients, patients on methadone usually require significantly higher doses of opioids to control their pain. Thus, the investigators feel that it would be unethical to restrict the dose that this subset of patients can receive.
• Use of other opioids or tramadol within past seven days: to avoid introducing bias related to opioid tolerance that may alter the response to the study medication thereby masking the medication's effect.
• Prior adverse reaction to opioids.
• Chronic pain syndrome: frequently recurrent or daily pain for at least 3 months results in alteration in pain perception which is thought to be due to down-regulation of pain receptors. Examples of chronic pain syndromes include sickle cell anemia, osteoarthritis, fibromyalgia, migraine, and peripheral neuropathies.
• Alcohol intoxication: the presence of alcohol intoxication as judged by the treating physician may alter perception, report, and treatment of pain.
• Systolic blood pressure <90 mm Hg: Opioids can produce peripheral vasodilation that may result in orthostatic hypotension.
• Oxygen saturation <95% on room air: For this study, oxygen saturation must be 95% or above on room air in order to be enrolled.
• Use of monoamine oxidase (MAO) inhibitors in past 30 days: MAO inhibitors have been reported to intensify the effects of at least one opioid drug causing anxiety, confusion and significant respiratory depression or coma.
• C02 measurement greater than 46: In accordance with a similar study (04-12-360), three subsets of patients will have their CO2 measured using a handheld capnometer prior to enrollment in the study. If the CO2 measurement is greater than 46, then the patient will be excluded from the study. The 3 subsets are as follows:

• All patients who have a history of chronic obstructive pulmonary disease (COPD)
• All patients who report a history of asthma together with greater than a 20 pack-year smoking history
• All patients reporting less than a 20 pack-year smoking history who are having an asthma exacerbation