[Understanding Oral and Nasal Mucosal Absorption of Fentanyl, and Rectal Absorption of Buprenorphine].

One of the key issues in the treatment of pain is to choose the appropriate route and dosage form of analgesics for each individual patient in pain. New drug forms of fentanyl absorbed by oral or nasal mucosa, and buprenorphine absorbed by rectal mucosa are described in this chapter. Only lipophilic opioids such as fentanyl and buprenorphine can be absorbed via the mucosa of oral or nasal cavity of the human body. The T max of rapid onset opioids (ROO) such as fentanyl buccal or sublingual tablets is the fastest among various dosage forms of opioid analgesics. However, such rapid increase in plasma concentration of fentanyl by ROO formulations may cause the risk of respiratory depression. Safe ways to use ROO analgesics are described.