Opioid antagonists have well-established indications in the reversal of life-threatening opioid toxicity, but also hold considerable promise for other applications in palliative care practice, particularly management of opioid-related constipation. We briefly review current understanding of opioid receptors, focusing on their complex role in gastrointestinal physiology. We summarize the pharmacology, conventional indications, and clinical usage of three major groups of opioid antagonists, including a promising new peripherally acting agent, methylnaltrexone, which is not commercially available. We suggest an approach to administering opioid antagonists for reduction of life-threatening opioid toxicity in patients with pain. The literature on opioid-induced constipation and its treatment with opioid-antagonists is reviewed in detail. Finally, other potential uses of opioid antagonists in palliative care are described, especially strategies for reducing such opioid side effects as nausea and pruritus and for improving analgesia or reducing tolerance by concomitantly administrating both an opioid agonist and low dosages of an antagonist.
Bibliographical noteFunding Information:
Dr. Billings is a Faculty Scholar of the Project on Death in America. This work was supported, in part, by a grant from the Robert Wood Johnson Foundation and by the John D. Stoeckle Center at the Massachusetts General Hospital.
- Gastrointestinal motility
- Narcotic antagonists
- Opioid-related disorders
- Respiratory depression
- Substace-related disorders
ASJC Scopus subject areas
- Clinical Neurology
- Anesthesiology and Pain Medicine