BACKGROUND The minimum local analgesic concentration (MLAC) has been defined as the median effective local analgesic concentration (EC50) in a 20-ml volume for epidural analgesia in the first stage of labor. The aim of this study was to determine the relative local anesthetic sparing efficacies of intravenous and epidural fentanyl by comparison of their effects on the MLAC of bupivacaine. MET...

BACKGROUND The modifying effects of fentanyl on protective airway reflexes have not been characterized in children. The aim of this study was to assess the impact of increasing doses of fentanyl on laryngeal reflex responses in children anesthetized with sevoflurane. The authors hypothesized that the incidence of laryngospasm evoked by laryngeal stimulation is reduced with increasing doses of f...

OBJECTIVES To compare patients' preference for transdermal fentanyl or sustained release oral morphine, their level of pain control, and their quality of life after treatment. DESIGN Randomised, multicentre, international, open label, crossover trial. SETTING 35 centres in Belgium, Canada, Denmark, Finland, the United Kingdom, the Netherlands, and South Africa. PARTICIPANTS 256 patients (...

Fentanyl is a basic amine shown to have extensive first-pass pulmonary uptake. To evaluate the role of the pulmonary endothelium in this uptake process, the simultaneous pharmacokinetics of [3H]fentanyl and two marker drugs, blue dextran, and [14C]antipyrine, were evaluated in a flow-through system of pulmonary endothelial cells. Fentanyl equilibrium kinetics were determined in a static culture...

Fentanyl is a potent mu opioid receptor agonist that was discovered to identify an improved human health analgesic over morphine, an opioid frequently associated with histamine-release, bradycardia, hyper- or hypotension, and prolonged postoperative respiratory depression. Historically, the pharmacological features of fentanyl have been described primarily through the study of the human approve...

15 Background: Ritonavir inhibition of cytochrome p450 3A4 decreases the elimination 16 clearance of fentanyl by 67%. We used a pharmacokinetic model developed from published 17 data to simulate the effect of sample patient-controlled epidural labor analgesic regimens on 18 plasma fentanyl concentrations in the absence and presence of ritonavir-induced cytochrome 19 p450 3A4 inhibition. 20 Meth...

Recently, decreased activity levels have been observed in pigs treated postoperatively with transdermal delivery of fentanyl (TD-fentanyl) after isoflurane anaesthesia. Whether the change in behaviour is related to opioid-induced sedation or to insufficient pain relief remains to be investigated. This study was therefore undertaken to evaluate the effect of TD-fentanyl 50 microg h(-1) on the ac...

Fentanyl is used for pain treatment during pregnancy in human beings and animals. However, fentanyl pharmacokinetics during pregnancy has not been fully established. The aim of this study was to characterize fentanyl pharmacokinetics in pregnant sheep after intravenous and transdermal dosing during surgical procedure performed to ewe and foetus. Pharmacokinetic parameters reported for non-pregn...

The synthetic opioid fentanyl undergoes extensive metabolism in humans. Systemic elimination occurs primarily by hepatic metabolism. When administered as a lozenge for oral transmucosal absorption, swallowed fentanyl is subject to first pass metabolism in the liver and possibly small intestine. Little is known, however, about the identity and formation of human fentanyl metabolites. This invest...