Primary Mucosal Routes of Opioid Administration for Treating Terminal Cancer Pain: Rectal, Buccal, and Intranasal Delivery.

Purpose: This review analyzes the factors influencing mucosal administration of opioids, the methods of administration, clinical applications, pharmacokinetic parameters, and considerations. Summary: Inclusion criteria for this review includes English literature from 1984 to the present, with the primary literature search conducted on PubMed. The findings indicate that mucosal administration of opioids offers a non-invasive and rapidly effective treatment option for chronic and breakthrough pain in terminal cancer patients, which is crucial for improving their quality of life. Specifically, rectal administration provides long-lasting analgesia but is slow-acting and has variable bioavailability. Oral administration is more patient-friendly and has higher bioavailability than rectal administration, though some of the drug may be swallowed. Nasal administration is well-tolerated, has higher bioavailability than the rectal and buccal routes, and acts quickly, but its effects are short-lived and the long-term impact on the nasal mucosa remains unclear. Conclusion: Current research shows that mucosal opioid administration can relieve pain in advanced cancer patients, but each route has pros and cons. Choosing the appropriate method and medication based on the patient's condition is crucial. Further research on integrating these routes to optimize pain management for terminal patients is needed.