Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0432222 (SEM)
 47,337 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effects of propofol, etomidate, midazolam, and fentanyl on motor evoked responses to transcranial stimulation (tc-MERs) were studied in five healthy human volunteers. Each subject, in four separate sessions, received intravenous bolus doses of propofol 2 mg.kg-1, etomidate 0.3 mg.kg-1, midazolam 0.05 mg.kg-1, and fentanyl 3 micrograms.kg-1. Electrical tc-MERs (tce-MERs) were elicited with anodal stimuli of 500-700 V. Magnetic tc-MERs (tcmag-MERs) were elicited using a Cadwell MES-10 magnetic stimulator at maximum output. Compound muscle action potentials were recorded from the tibialis anterior muscle. Duplicate tce-MERs and tcmag-MERs were recorded before and up to 30 min after drug injection. Reproducible baseline tce-MERs (amplitude 4.7 +/- 0.43 (SEM) mV, latency 29.4 +/- 0.35 ms) and tcmag-MERs (amplitude 3.7 +/- 0.43 mV, latency 31.1 +/- 0.39 ms) were obtained in all subjects. Pronounced depression of tce-MER amplitude to 2% of baseline values (P less than 0.01) was observed 2 min after injection of propofol. Thirty minutes after injection of propofol, amplitude depression to 44% of baseline (P less than 0.05) was still present, despite an apparent lack of sedation. Midazolam caused significant (P less than 0.01) amplitude depression, e.g., tcmag-MER to 16% of baseline values 5 min after injection. Significant depression persisted throughout the 30-min study period. Fentanyl did not cause any statistically significant amplitude changes in this small population. Etomidate caused significant but transient depression of tc-MER amplitude. However, there was considerable intersubject variability. Latency did not change significantly after any drug.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Effects of propofol, etomidate, midazolam, and fentanyl on motor evoked responses to transcranial electrical or magnetic stimulation in humans. 155 Feb 74

Fentanyl, a mu selective opioid agonist in wide clinical use, raises the ventricular fibrillation threshold in the normal canine myocardium. We have previously shown that this effect is amplified by haemorrhagic stress. In order to determine if mu receptor activation is antifibrillatory during acute myocardial ischaemia, we compared the effects of two mu selective agents, fentanyl and buprenorphine, in open chest chloralose anaesthetised dogs. Each drug was administered intravenously in two doses 1 h apart (fentanyl 30 micrograms.kg-1.dose; buprenorphine 0.3 mg.kg-1.dose). Ventricular fibrillation threshold was measured during right ventricular pacing using the single stimulus technique. The threshold was determined before and during a 10 min left anterior descending coronary artery occlusion. Prior to fentanyl administration, ventricular fibrillation threshold decreased from a control value of 19(SEM 2) mA to 12(1) mA during coronary artery occlusion. After the first dose of this drug an attenuation in the ischaemia induced fall in fibrillation threshold from 23(4) mA to 15(2) mA was observed. After the second dose of fentanyl the decline in fibrillation threshold was significantly blunted at 22(4) mA during control and 18(3) mA during occlusion, p less than 0.05 compared to no drug. In an additional series of experiments atropine sulphate abolished the antifibrillatory action of fentanyl, indicating that vagal efferent activation is responsible for the protective effect of the drug during acute myocardial ischaemia. This is in contrast with its mode of action during haemorrhage, when it enhances vagal afferent inhibition of sympathetic tone, and atropine pretreatment is without effect.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Comparative effects of the opioids fentanyl and buprenorphine on ventricular vulnerability during acute coronary artery occlusion. 255 6

The effects of intrathecal midazolam and fentanyl on electrical current threshold for pain were measured using stimulating electrodes in the neck and tail of rats with chronically implanted lumbar subarachnoid catheters. This involved the measurement of the minimum current (50 Hz 2 ms pulses 0-5 mA), which made the rat squeak when applied alternately to electrodes at each skin site. The responses measured in milliamperes were expressed as a number of times control readings. Equieffective doses of both midazolam and fentanyl produced a significant increase in electrical threshold for pain in the tail (mean +/- SEM 3.14 +/- 0.51 and 2.89 +/- 0.35: P less than 0.05; Wilcoxon sum rank test) in the absence of any change in the neck (mean +/- SEM 1.28 +/- 0.13 and 0.96 +/- 0.12, NS), thus demonstrating a spinal effect. Fentanyl caused a significant simultaneous increase in tail flick latency (mean +/- SEM 67.8 +/- 20.1%, P less than 0.05), but midazolam did not (mean +/- SEM 4.22 +/- 2.76%, NS). Intraperitoneal injections of naloxone (0.25 mg/kg) blocked the response to fentanyl in both tests and did not affect the response to midazolam. Intraperitoneal flumazenil (5 mg/kg) blocked the midazolam antinociceptive effect but did not affect the response to fentanyl in either test. Tail withdrawal in response to non-noxious stimulation was preserved in all animals with spinal analgesia, indicating that myelinated afferent and efferent pathways were still functioning. Righting reflex, coordination, motor power, and alertness were also preserved in the presence of both drugs. Both drugs caused spinally mediated antinociceptive effects that were qualitatively different.
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PMID:Intrathecal midazolam and fentanyl in the rat: evidence for different spinal antinociceptive effects. 271 11

The pharmacokinetics of fentanyl were studied in fourteen neonates undergoing major surgical procedures. Five patients were less than 1 day of age, seven were 1-4 days old, and two were 7-14 days old. Fentanyl was given intravenously, 10 micrograms/kg (n = 1), 25 micrograms/kg (n = 4), or 50 micrograms/kg (n = 9), and plasma concentrations measured at intervals of up to 18 hr. Average weight was 2.9 kg. The injection of 25 or 50 micrograms/kg of fentanyl over 1-3 min was hemodynamically well-tolerated by all patients. Four newborns without respiratory impairment secondary to surgery or disease needed ventilatory support for an average of 24 hr (range 11-40 hr). Plasma concentrations of fentanyl were most appropriately described by a two-compartment model. The mean +/- SEM values of selected model parameters were volume of the central compartment, 1.45 +/- 0.34 L/kg; volume of distribution at steady state, 5.1 +/- 1 L/kg; clearance, 17.94 +/- 4.38 ml X kg-1 X min-1; and terminal elimination half-life (t 1/2 beta), 317 +/- 70 min. In seven patients transient rebound in plasma fentanyl concentrations of 0.5 ng/ml or greater occurred. In three patients with markedly increased intraabdominal pressure, the t 1/2 beta was 1.5-3 times the population mean. Thus fentanyl disposition in neonates is highly variable, but the t 1/2 beta is predictably prolonged in the presence of increased abdominal pressure.
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PMID:Pharmacokinetics of fentanyl in neonates. 395 90

Cerebral blood volume (CBV) and intracranial (ICP) were examined in dogs during 3.5 h anesthesia with isoflurane (1.4% expired) or fentanyl (continuous intravenous infusion), and after decreasing the concentration of isoflurane to less than 0.15% expired or discontinuing administration of fentanyl. Isoflurane (1.4%) increased CBV 9-11% for greater than 3 h but increased ICP for only the first 21.7 +/- 1.4 min (mean +/- SEM). Fentanyl decreased CBV 7-10% for greater than 3 h but decreased ICP for only the first 20.3 +/- 2.7 min. Because both halothane or enflurane increase ICP for greater than 3 h in this model, both isoflurane or fentanyl may be preferred to halothane or enflurane for patients at risk for increased ICP.
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PMID:Relationship between cerebral blood volume and CSF pressure during anesthesia with isoflurane or fentanyl in dogs. 673 13

Using the open ventriculocisternal perfusion method, the rate of cerebrospinal fluid (CSF) production was examined in dogs anesthetized with either halothane (0.8%) or fentanyl (3.0 micrograms/kg/min for 20 min, then 0.2 micrograms/kg/min, intravenously), and nitrous oxide (60-70%) in oxygen. Halothane decreased the mean rate of CSF production from 0.047 +/- 0.006 ml/min (mean +/- SEM) in controls to 0.033 +/- 0.005 ml/min. This effect persisted throughout 3.0-3.5 h of anesthesia. When the expired concentration of halothane was decreased from 0.8% to less than 0.1%, the mean rate of CSF production returned to control values within 45-50 min. Fentanyl produced no change in the mean rate of CSF production compared to controls. These data suggest that increased CSF volume does not contribute to increased intracranial pressure during prolonged halothane anesthesia. In patients at risk for increased intracranial pressure due to increased CSF volume, either halothane or fentanyl may be preferable to anesthetics that may increase CSF production, e.g., enflurane.
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PMID:Effects of halothane and fentanyl on the rate of CSF production in dogs. 684 81

Five patients undergoing endoscopic injection of oesophageal varices were anaesthetised with etomidate 0.2 mg/kg followed by an infusion at a rate of 20 micrograms/kg/minute. Fentanyl 100-200 micrograms was also given intravenously and the patients' lungs were ventilated with oxygen in air. The postinfusion plasma etomidate concentration was described by a three compartment model with a mean half-life of 540 minutes (SEM 66.9) and volume of distribution of 8.9 litres/kg (SEM 0.6). Clearance was 12.7 ml/kg/minute (SEM 2.3). Compared to results in the literature obtained from normal patients, these cirrhotic patients had normal clearance rates, but the distribution volume and elimination half-life were twice as great. This suggests that cirrhotic patients metabolise etomidate normally, but the volume of distribution is doubled, thus resulting in prolonged elimination half-lives.
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PMID:Etomidate anaesthesia in patients with cirrhosis of the liver: pharmacokinetic data. 686 58

Fentanyl 50 micrograms, bupivacaine 50 mg and two mixtures containing fentanyl 50 micrograms and bupivacaine 25 mg or 12.5 mg (0.25 and 0.125%), respectively, in a volume of 10 ml were administered via thoracic extradural catheters to 24 patients after major abdominal surgery. All patients received all four treatments, in a randomized order, so that each patient received one of the 24 possible combinations of the four treatments. Pain relief was assessed by a linear analogue pain scale and the Prince Henry Hospital pain score. The duration of pain relief, effects on ventilatory frequency, heart rate, arterial pressure and central venous pressure were also recorded. Mean reductions in the analogue pain scale for fentanyl, bupivacaine, and fentanyl in 0.25% and 0.125% bupivacaine were 80 (SEM 5) %, 87 (4) %, 86 (5) % and 77 (5) %, respectively (ns). Pain scores decreased by 62 (6) %, 83 (5) %, 77 (6) % and 72 (6) %, respectively (ns). Mean arterial pressure decreased to 90 (2) %, 70 (2) %, 81 (2) % and 82 (3) %, respectively, of pretreatment values. In this respect, bupivacaine alone was significantly different from the three other treatments (P < 0.001). Hypotension (reduction in arterial pressure greater than 25% of pretreatment mean arterial pressure) was also more frequent after bupivacaine alone (P < 0.01). Effects on ventilation, heart rate and central venous pressure did not differ between the four treatments.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Comparison of extradural fentanyl, bupivacaine and two fentanyl-bupivacaine mixtures of pain relief after abdominal surgery. 788 Jul 3

Classically, opioids inhibit Ca2+ influx, but recent reports suggest opioids may also stimulate Ca2+ entry. Therefore, we have measured the effect of opioids on intracellular Ca2+ ([Ca2+]i), fluorimetrically, in Fura-2-loaded SH-SY5Y cells. Fentanyl 0.3 mumol litre-1 caused a mean increase in [Ca2+]i of 18.8 (SEM 2.1) nmol litre-1 in some (30.3%) batches of SH-SY5Y cells. In responding cells, the fentanyl-induced increase in [Ca2+]i was dose-dependent, with an EC50 of 0.73 mumol litre-1. This response was naloxone-reversible, and the delta opioid agonist [D-Pen2,5]enkephalin had no effect on [Ca2+]i, suggesting the fentanyl-induced Ca2+ response was entirely mediated by the mu opioid receptor. Fentanyl 0.3 mumol litre-1 increased [Ca2+]i without preactivation of phospholipase C by another agonist, and this was markedly reduced by Ni2+ 2.5 mmol litre-1. These data suggest that mu opioids directly increase [Ca2+]i by stimulating Ca2+ influx in SH-SY5Y cells.
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PMID:Fentanyl increases intracellular Ca2+ concentrations in SH-SY5Y cells. 878 53

Fentanyl has been incorporated into a transdermal therapeutic system (TTS) containing a rate-limiting membrane that provides constant release of the opioid. TTS fentanyl provides continuous opioid delivery for up to 72 hr without the need for special equipment. After Institutional Review Board approval, 53 patients with cancer pain requiring 45 mg or more of oral morphine daily were admitted into an open-label, prospective, multicenter evaluation of TTS fentanyl for the relief of pain. After a 1-week stabilization on oral morphine, patients were transferred from morphine to an appropriate dose of TTS-fentanyl (25, 50, 75, or 100 micrograms/hr) administered as a transdermal patch every 3 days. TTS fentanyl was titrated to pain relief, and patients were followed up for as long as 3 months. Pain relief and the side effects of the medications were assessed daily. Twenty-six men and 27 women with a mean (+/- SD) age of 61 (+/- 12) years entered the study; 23 patients completed the full 84-day study. The mean duration of TTS fentanyl use was 58 +/- 32 days. The mean (+/- SEM) daily morphine dose during the last 2 days of stabilization was 189 (+/- 20) mg, and the mean initial fentanyl patch dose was 58 (+/- 6) micrograms/hr. The mean daily morphine dose taken "as needed" for breakthrough pain at study completion was 35 mg. The mean final fentanyl dosage at study completion was 169 (+/- 29) micrograms/hr. Pain relief was rated as good or excellent by 82% of patients during the treatment period. When asked to compare pain relief during the first month of TTS-fentanyl use to that provided by their last analgesic before study entry, 63% preferred TTS fentanyl. Side effects considered related to the fentanyl patch were nausea (13%), vomiting (8%), skin rash (8%), and drowsiness (4%). Thirty percent of patients reported adverse experiences related to the fentanyl patch, and 17% had to be discontinued from the study. We conclude that TTS fentanyl administered every 3 days for the treatment of cancer pain is effective, safe, and well tolerated by most patients.
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PMID:A clinical evaluation of transdermal therapeutic system fentanyl for the treatment of cancer pain. 973 1


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