Opiates in Special Age Groups ~ Applied Therapeutics

Opiates in Special Age Groups

Advanced Age

61. B.V., a 75-year-old woman, is seen in the office for a routine physical examination. She has a history of osteoarthritis in both knees, osteoporotic vertebral disease, and peptic ulcer disease. In addition to estrogen and calcium supplementation, B.V. takes acetaminophen 650 mg every 4 hours during the day for general discomfort and ibuprofen 400 mg every night to “help [her] sleep.” What further information should be assessed before modifying B.V.'s drug therapy?

Chronic pain can have a significant impact on daily functioning and quality of life and should be recognized as a significant problem requiring prompt attention. Chronic pain is common in older adults and may easily go unrecognized and untreated. Painful conditions affecting bones and joints often develop as people age. These conditions provide a chronic source of pain and are often incurable. Approximately one of five older adults takes analgesic medications regularly and more than half of these patients have taken prescription analgesics for >6 months. Prevalence rates for chronic pain among community-dwelling older people have been estimated to be between 25% and 50%.²⁰⁸ Studies of nursing home residents have documented similar rates for chronic nonmalignant pain and also have shown a consistent trend toward undertreatment with analgesics.²⁰⁹^,²¹⁰

Clinical practice guidelines have been developed for the management of chronic pain in older persons.²⁰⁸ All older patients should be assessed for evidence of chronic pain as well as for acute pain that may indicate a new illness or exacerbation of a chronic condition. Older patients may be reluctant to report pain because they may fear the consequences of a diagnostic workup. Older adults may also perceive pain to be synonymous with serious disease or death.²⁰⁸ When providing a history, they may not use the word “pain” to describe how they feel. Instead, they may describe their discomfort as “aching, soreness, burning, or tightness.” Finally, patients with dementia or language deficits may not be able to communicate the presence of pain. In these individuals and others, grimacing or other unusual behavior may provide clues to the presence of pain.

B.V. should receive a comprehensive assessment that includes a complete medical history and physical examination to determine any new underlying causes of pain, sensory deficits, or neurologic abnormalities. Physical function and pain associated with activities of daily living should be assessed as well as her psychosocial function to evaluate her for depression and to understand her social network and support system. A thorough evaluation of current pain should be performed to characterize her pain and to determine the patterns of her analgesic use and their effectiveness. The medication history should be reviewed for potential drug side effects and interactions. B.V.'s use of ibuprofen should be further evaluated, because older patients who use NSAID chronically have a higher frequency of GI bleeding, especially if they have a previous history of this condition.²⁰⁸

62. When asked, B.V. states that her current pain level is a 7 on a 10-point scale, and that it can vary from 4 to 8 during the day. It is usually better after rest and worsens later in the day, especially after physical exertion. Although she takes acetaminophen and ibuprofen regularly, they do not effectively reduce her pain. B.V. realizes that her current medical condition will probably not allow her to be completely pain free and states that a pain level of 3 would be acceptable. Would opiate analgesics be appropriate to control B.V.'s pain?

The use of opioid analgesic for chronic nonmalignant pain is controversial. The usefulness of this class of drugs should not be overlooked, however, and may provide fewer risks than long-term or high-dose NSAID therapy. The doses needed are often much smaller than those needed to treat chronic malignant pain. Older patients often experience greater pain relief from opioid analgesics than do younger patients, probably because both the extent and duration of analgesia are enhanced in this group.²¹¹^,²¹² Older patients achieve higher-than-expected plasma opioid levels (compared with younger patients) after IM or IV administration. Physiologic changes associated with aging, such as decreases in lean body mass, renal function, plasma proteins, hepatic blood flow, and hepatic metabolism,²¹³^,²¹⁴ may be responsible for the enhanced activity of opioids in older patients.²¹⁵

When initiating opioid or adjunct analgesics in older patients, it is important to remember the phrase “start low and go slow.” Because B.V. has underlying conditions that cause continuous pain, time-contingent dosing will be more beneficial. An appropriate initial regimen for B.V. using oxycodone HCl 2.5 mg and acetaminophen 325 mg would be one tablet orally every 6 hours, with one tablet every 4 hours as needed. This would provide continuous analgesic therapy throughout the day and allow B.V. flexibility to take an additional dose before activities that may exacerbate her pain. B.V. should be instructed to discontinue taking ibuprofen and to avoid other products containing acetaminophen. B.V. may also respond to tramadol 25 to 50 mg (i.e., 1/2–1 tablet) every 8 hours for her pain, because it has shown efficacy equivalent to NSAIDs in osteoarthritis pain. This agent can be considered as an alternative to a high-potency analgesic, but still presents a risk of dizziness and drowsiness.

B.V. should be monitored closely for sedation that could affect her concentration and ability to perform her activities of daily living. Because older patients are more sensitive to the constipating side effects of opioids, a bowel regimen consisting of a stimulant laxative and stool softener should be started at the beginning of therapy. Patients also should be encouraged to maintain good fluid intake and to include fruits and vegetables that are high in fiber in their diet. B.V.'s therapy should be adjusted based on careful monitoring for efficacy and side effects.