When are opioids prescribed for cancer pain? How do they work?
Opioids are prescribed for cancer pain when other modalities (procedural, pharmacologic, and nonpharmacologic) fail to provide analgesia sufficient to allow achievement of realistic patient goals, including maintenance of function (activities of daily living) and overall quality of life. Opioids are pharmaceutical agents with morphine-like effects; they are opioid-receptor (mu, kappa, delta, etc.) agonists that will reliably provide analgesia at therapeutic dosages. Opioid analgesics are available in several formulations for oral, subcutaneous, intravenous, and transdermal administration, which makes them a mainstay of the armamentarium against cancer pain.