Rational Use of Sublingual Opioids in Palliative Medicine

Abstract

The sublingual administration of opioid analgesics has been a mainstay in the pain management of homebound dying hospice patients who are no longer able to swallow. It is also a potentially useful route of administration in other situations in which the oral route is not available and other routes are impractical or inappropriate. Potential advantages of the sublingual route include rapid analgesic onset and avoidance of hepatic first-pass metabolism. Pharmacokinetic and pharmacodynamic studies have yielded widely disparate data on sublingual morphine. Other opioids have been less studied. Available data suggests limited sublingual availability of hydrophilic opioids (e.g., morphine, oxycodone, and hydromorphone) and superior absorption of the lipophilic opioids (e.g., methadone and the fentanils). Buprenorphine, a potent, lipophilic, partial mu-opioid receptor agonist, appears promising but awaits further study.

Alternative Routes to Oral Opioid Administration in Palliative Care: A Review and Clinical Summary

“…Pharmacokinetic data indicated that blood levels of morphine following sublingual administration do not rise faster than those following oral administration. In a more recent review, Reisfield & Wilson [90] supported the conclusions of Coluzzi [99] regarding morphine and extended these conclusions to oxycodone and hydromorphone as well. No studies of the use of sublingual morphine in non‐hospice palliative care patients were identified.…”

“…Cautions and Considerations Disadvantages of this route include bitter taste, burning sensation, possible ulceration, and need to retain the drug sublingually for several minutes [16,[89][90][91]99]. Patients are required to avoid eating or drinking until the medication has been completely dissolved.…”

Oral Transmucosal Delivery for Improved Drug Bioavailability and Patient Compliance

“…in less than 15 min. In case of sublingual spray, the drug is readily available in dissolved form and upon spray as fine mist, rapidly absorbs into systemic circulation [3]. Rapid pharmacological response is highly desirable in certain cases such as breakthrough pain.…”

In vitro and in vivo evaluation of a sublingual fentanyl wafer formulation

“…Interest in noninvasive but fast-acting formulations for opioid administration has generated investigation of the sublingual route 7,8. Compared with the transmucosal and buccal routes, the sublingual route may be even more attractive for fentanyl delivery 9–11.…”