Management of Opioid-Induced Gastrointestinal Effects
Opioid-induced gastrointestinal side effects, namely, nausea and constipation, are bothersome yet often easy to manage. Due to their widespread frequency, it is imperative that prophylactic and treatment modalities be understood. Although many pharmacotherapeutic agents are available with which to prevent or treat these side effects, few randomized, placebo-controlled studies have been conducted in terminally ill patients, thus limiting most treatment decisions to empiric therapies based on extrapolated data. A strong understanding of the pathophysiology of the sequelae is therefore paramount. Common agents administered for nausea are butyrophenones, pheno-thiazines, metoclopramide, and serotonin-receptor antagonists. Those given to manage constipation are stimulant laxatives and stool softeners, individually or in combination.
Nausea and constipation are side effects that may be experienced by terminally ill patients receiving palliative opioid analgesics. The World Health Organization defines palliative care as "the active total care of patients whose disease is not responsive to curative treatment. Control of pain, of other symptoms, and of psychological, social and spiritual problems, is paramount." This includes patients with cancer but encompasses all terminally ill patients.
Surveys indicate that 50-60% of patients enrolled in hospice programs may experience nausea, constipation, or both, with prevalence rates as high as 40% in the last 6 weeks of life. Of these patients, as many as 80% may require an opioid for pain relief. In a study of 260 patients with cancer pain receiving opioids, nausea was rated as moderate to severe in 8.3-18.3%, regardless of the drug. This suggests that patients receiving palliative care frequently experience nausea and constipation, and opioids contribute significantly to these symptoms. It is difficult to determine the exact etiology of these symptoms in the terminally ill population due to other underlying processes such as dehydration, cerebral metastases, and intestinal obstruction. Nausea and constipation may be dose related, with nausea generally subsiding within the first several days after starting therapy. Unfortunately, constipation may remain a constant problem and usually does not abate with continued therapy.
Opioid-induced nausea may cause apprehension in patients receiving palliative care. It is estimated that 6-12% of these patients may experience nausea, with some studies reporting its occurrence as high as 29%. Often it may be difficult to differentiate the cause of opioid-induced nausea due to various comorbidities, conditions, and concomitant drugs, thus skewing an accurate estimate of its true frequency. Patients often may associate nausea with a recent opioid analgesic, creating potential barriers to effective pain management in the form of anticipatory nausea, anxiety, or adherence problems. Nausea and vomiting may greatly affect patient-reported quality of life scores. In addition, nutrition intake may be limited due to nausea, which also adversely affects quality of life. Constipation, which may be a result of several patient-specific variables, is a large concern and also may adversely affect quality of life. Because the goal of palliative care is symptom management, it is extremely important to understand the symptoms experienced by these patients as a result of prescribed drug therapy.
Due to the paucity of clinical data to guide practitioners in the treatment of opioid-induced gastrointestinal side effects in palliative care, much clinical practice is theoretical, or extrapolated from different patient populations experiencing these symptoms due to different etiologies.
Abstract and Introduction
Abstract
Opioid-induced gastrointestinal side effects, namely, nausea and constipation, are bothersome yet often easy to manage. Due to their widespread frequency, it is imperative that prophylactic and treatment modalities be understood. Although many pharmacotherapeutic agents are available with which to prevent or treat these side effects, few randomized, placebo-controlled studies have been conducted in terminally ill patients, thus limiting most treatment decisions to empiric therapies based on extrapolated data. A strong understanding of the pathophysiology of the sequelae is therefore paramount. Common agents administered for nausea are butyrophenones, pheno-thiazines, metoclopramide, and serotonin-receptor antagonists. Those given to manage constipation are stimulant laxatives and stool softeners, individually or in combination.
Introduction
Nausea and constipation are side effects that may be experienced by terminally ill patients receiving palliative opioid analgesics. The World Health Organization defines palliative care as "the active total care of patients whose disease is not responsive to curative treatment. Control of pain, of other symptoms, and of psychological, social and spiritual problems, is paramount." This includes patients with cancer but encompasses all terminally ill patients.
Surveys indicate that 50-60% of patients enrolled in hospice programs may experience nausea, constipation, or both, with prevalence rates as high as 40% in the last 6 weeks of life. Of these patients, as many as 80% may require an opioid for pain relief. In a study of 260 patients with cancer pain receiving opioids, nausea was rated as moderate to severe in 8.3-18.3%, regardless of the drug. This suggests that patients receiving palliative care frequently experience nausea and constipation, and opioids contribute significantly to these symptoms. It is difficult to determine the exact etiology of these symptoms in the terminally ill population due to other underlying processes such as dehydration, cerebral metastases, and intestinal obstruction. Nausea and constipation may be dose related, with nausea generally subsiding within the first several days after starting therapy. Unfortunately, constipation may remain a constant problem and usually does not abate with continued therapy.
Opioid-induced nausea may cause apprehension in patients receiving palliative care. It is estimated that 6-12% of these patients may experience nausea, with some studies reporting its occurrence as high as 29%. Often it may be difficult to differentiate the cause of opioid-induced nausea due to various comorbidities, conditions, and concomitant drugs, thus skewing an accurate estimate of its true frequency. Patients often may associate nausea with a recent opioid analgesic, creating potential barriers to effective pain management in the form of anticipatory nausea, anxiety, or adherence problems. Nausea and vomiting may greatly affect patient-reported quality of life scores. In addition, nutrition intake may be limited due to nausea, which also adversely affects quality of life. Constipation, which may be a result of several patient-specific variables, is a large concern and also may adversely affect quality of life. Because the goal of palliative care is symptom management, it is extremely important to understand the symptoms experienced by these patients as a result of prescribed drug therapy.
Due to the paucity of clinical data to guide practitioners in the treatment of opioid-induced gastrointestinal side effects in palliative care, much clinical practice is theoretical, or extrapolated from different patient populations experiencing these symptoms due to different etiologies.