Abstract
Pain, by definition, is a subjective phenomenon. The subjective component in chronic pain due to cancer is very important. Opioid analgesics are the mainstay of treatment for cancer pain. Their use should be optimized to provide adequate pain relief. Optimal use includes understanding the concepts of tolerance, physical dependence, and psychological dependence. None of these should limit or inhibit pain management. Optimal use also includes familiarity with the clinical use of opioids. Regular use is generally preferred over “prn” use. Increased parenteral versus oral effectiveness of opioids, secondary to a high first-pass effect, is an important consideration when routes of administration must be altered. Familiarity with approximate equianalgesic doses allows for conversion from one opioid to another. Such conversion might help increase the convenience, increase the efficacy, or decrease the adverse effects of an opioid regimen. Knowledge of durations of action of opioids helps in the selection of dosing intervals to facilitate continuous pain relief. Morphine is the most common opioid chosen for cancer pain management, but others may be equally effective. Follow-up assessments with subsequent alterations are as important as the initial selection of drug, dose, and dosing interval. Adjuvant analgesics, such as nonsteroidal antiinflammatory drugs, anticonvulsants, or antidepressants, may enhance pain relief, especially in certain pain syndromes (eg, metastatic bone pain, neuropathic pain). These agents are usually used in addition to opioids.
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