Review articles : Transdermal and inhalatory routes of opioid administration: the potential application in cancer pain

Abstract

The aim of this paper is a review of the data in the literature on the transdermal and inhalatory routes of opioid administration. The majority of the published experience is based on the use of transdermal and inhalatory opioids for the management of postoperative pain. Pharmacokinetic data suggest that transdermal fentanyl is well absorbed although there is a considerable delay in reaching steady state plasma level and also a slowly declining plasma concentration after removal of the transdermal patch. Clinical experience suggests that it is well-tolerated. There is very limited knowledge about the absorption and pharmacokinetics of morphine when given by the inhalatory route. A better understanding of the absorption and pharmacokinetics of different nebulized opioids is needed before reliable clinical trials can be designed on these drugs.