ABSTRACT
Worldwide, intramuscular opioid administration is the mainstay in the management of postoperative pain. Intravenous patient-controlled opioid analgesia with computerized pumps, allows the patient to titrate the drug concentration until a desired level of analgesia is reached and has gained wide popularity in several western countries. Most opioid products are formulated as liquids which can be delivered by metered spray pumps. High permeability to drugs and abundant blood flow make mucosal opioid administration highly promising. Most opioids are highly ionized in acid environments and unable to penetrate gastric mucosa. Most opioid products are formulated as liquids which can be delivered by metered spray pumps. A new bidirectional nasal delivery system has demonstrated improved drug distribution. It takes advantage of the posterior connection between the nasal passages when the velum closes during oral exhalation, but has so far not been applied for opioid administration.
