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PubMed2004

Pentobarbital versus medetomidine-ketamine-fentanyl anaesthesia: effects on haemodynamics and the incidence of ischaemia-induced ventricular fibrillation in swine.

The present study was performed to compare haemodynamic variables at baseline and the incidence of ventricular fibrillation during the early phase of ischaemia in swine during pentobarbital or medetomidine-ketamine-fentanyl anaesthesia. Twenty-two swine (mean +/- SD: 29+/- 3 kg) were anaesthetized with sodium pentobarbital (induction with 36 mg/kg intraperitoneally, and maintenance with 5-20 mg/kg/h intravenously [i.v.]) and 6 swine (27+/- 3 kg) were anaesthetized with ketamine and fentanyl (premedicated with medetomidine 0.1 mg/kg and ketamine 10 mg/kg intramuscularly, induction with ketamine 20 mg/kg and fentanyl 0.025 mg/kg i.v., and maintenance with ketamine 20 mg/kg/h and fentanyl 0.025 mg/kg/h i.v.). After a stabilization period of 30 min, the left anterior descending coronary artery (LAD) was occluded for 10 min. Haemodynamic data and occurrence of ventricular fibrillation were recorded. The ischaemic area was measured by fluorescing microspheres. Swine anaesthetized with medetomidine-ketamine-fentanyl had significantly lower heart rate, myocardial contractility, peak left ventricular pressure, arterial blood pressure, aortic blood flow, myocardial blood flow and cardiac index at baseline, than swine anaesthetized with pentobarbital. Whereas none of the swine anaesthetized with pentobarbital fibrillated during the LAD occlusion, ventricular fibrillation occurred in 83% of the animals anaesthetized with medetomidine-ketamine-fentanyl (P< 0.001). No significant difference was found in size of ischaemic area between the two groups. Thus, we show a depression in haemodynamic variables at baseline and a higher incidence of ventricular fibrillation during the early phase of ischaemia in swine anaesthetized with medetomidine-ketamine-fentanyl compared to swine anaesthetized with pentobarbital.

Anesthesia↗
PubMedDate not supplied

[Withdrawal syndrome associated with cessation of fentanyl and midazolam in pediatrics].

PURPOSE: To determine the incidence of abstinence syndrome in children interned in the Pediatric Intensive Care Unit (PICU) in fentanyl use and midazolam. METHODS: Evaluation of 36 children interned in PICU of the Hospital São Paulo--Federal University of São Paulo, in the period from March to September 1997, with age varying from 5 days to 22 months (22 masc: 14 fem) who used fentanyl use and midazolam for more than 24 hours. Used the Escore Neonatal of Abstinence adapted by Finnegan determines the occurrence of abstinence syndrome in was used to children 2 years old or less. Sustain larger or equal for 8 is considered as abstinence syndrome. Correlated the abstinence syndrome with the accumulated total dose, infusion velocity, daily dose and time of use of the fentanyl and midazolam. RESULTS: Certain abstinence syndrome in 18 (50%) of the 36 children. Applied Mann Whitney's statistical test to compare the groups with and without abstinence syndrome. Dose accumulated of fentanyl total (5732.7 +/- 5114.91 vs 624.2 +/- 591.2 mcg, p < 0.005), dose daily of fentanyl (98.54 +/- 6.12 vs 36.23 +/- 23.42 mcg/Kg/dia, p < 0.005), velocity of infusion of the fentayl (4.09 +/- 2.75 vs 1.5 +/- 0.95 mcg/Kg/hora, p < 0.005), time of use of the fentanyl (10.2 +/- 5.1 vs 3.16 +/- 1.09 days, p < 0.005), dose accumulated of midazolam total (118.8 +/- 86.97 vs 20.03 +/- 14.79 mg, p < 0.005), dose daily of midazolam (2.32 +/- 0.86 vs 1.21 +/- 0.68 mg/Kg/dia, p < 0.005), velocity of midazolam infusion (0.13 +/- 0.16 vs 0.05 +/- 0.02 mg/Kg/hora, p < 0.005) and time of use of the midazolam (9.20 +/- 4.67 vs 2.55 +/- 1.54 days, p < 0.005) they were considered significant. CONCLUSION: The abstinence syndrome presents an elevated incidence in children interned in PICU owing to the interruption of the fentanyl infusion and midazolam and in these patients it was related with the dose and the time of use.

Adjuvants, Anesthesia↗
PubMed2004

Clinical experience with transdermal fentanyl for the treatment of cancer pain in Germany.

The transdermal therapeutic system with fentanyl was released in Germany in 1995. Before and after the release several clinical trials were performed in our pain management unit and in other German pain centers, showing good efficacy after initial dose titration with intravenous patient-controlled analgesia or switching from pretreatment with oral morphine or other opioids. A sequential trial showed less use of laxatives with transdermal fentanyl compared to pretreatment with oral morphine. Safety and efficacy of the transdermal system in clinical practice were confirmed in a nationwide survey with 1005 patients, nearly all of them with cancer pain. Most patients had been treated with opioids, though 22% had received no opioids or only as required before initiation of transdermal fentanyl. The mean duration of transdermal treatment was 71 +/- 83 days. Pain relief with transdermal therapy was swift and efficient. Adverse events with the possibility of a causal relationship to transdermal therapy were documented for 26% of the patients, most frequently nausea, vomiting, constipation and drowsiness. Severe neurotoxic or respiratory complications were reported only rarely. Problems with transdermal application were reported by 12% of the patients, with patch detachment and dermatologic symptoms on the site of application being most frequent. Most patients showered regularly with the patches and only three patients reported that patches became loose under the shower or in the bathtub. In a recent prospective trial driving ability was tested in patients with continuous non-cancer pain, who had received stable doses of transdermal fentanyl. Data were available from 90 healthy volunteers matched to 30 patients, of whom 9 were excluded from the analysis because they took additional drugs in violation of the protocol. None of the performance measures for the 21 remaining fentanyl patients was significantly inferior to the controls. In conclusion, experience with the transdermal therapeutic system with fentanyl has been gathered in clinical trials, a large nationwide survey and clinical practice since the release in 1995. The conversion table based on a conversion ratio of 100 : 1 was safe and efficient in trials and clinical practice. Transdermal fentanyl has become a wellknown and frequently used opioid in the treatment of chronic cancer and non-cancer pain in Germany.

Administration, Cutaneous↗
PubMed2000

Pharmacokinetics and cardiopulmonary effects of fentanyl in isoflurane-anesthetized rhesus monkeys (Macaca mulatta).

OBJECTIVE: To determine pharmacokinetics and selected cardiopulmonary effects of fentanyl in isoflurane-anesthetized rhesus monkeys. ANIMALS: 6 adult male rhesus monkeys. PROCEDURE: Fentanyl (8 mg/kg of body weight, IV) was administered to 6 monkeys anesthetized with isoflurane. End-tidal isoflurane concentration and esophageal temperature were kept constant, and ventilation was mechanically assisted. Heart rate, rhythm, aortic blood pressure, and blood pH, gas, and fentanyl concentrations were determined before and for 8 hours after administration of fentanyl. Pharmacokinetics of fentanyl were derived by use of noncompartmental methods based on statistical moment theory. RESULTS: Heart rate and mean arterial pressure decreased transiently following fentanyl administration. Maximal decreases were observed 5 to 15 minutes after administration. Arterial pH, Paco2, and Pao2 ranged from 7.46 +/- 0.04 to 751 +/- 0.05 units, 29.2 +/- 3 to 34.6 +/- 4.4 mm Hg, and 412.6 +/- 105.3 to 482.9 +/- 71.2 mm Hg, respectively. The clearance, volume of distribution area, volume of distribution steady state, mean residence time, area under the curve, elimination rate constant, and half-life were 32.5 +/- 2.48 ml/kg/min, 9.04 +/- 1.91 L/kg, 70 +/- 1.2 L/kg, 218.5 +/- 35.5 min, 0.247 +/- 0.019 mg/ml/min, 0.004 + 0.001/min, and 192.0 +/- 33.5 min, respectively. CONCLUSIONS AND CLINICAL RELEVANCE: Transient but potentially clinically important decreases in heart rate and mean arterial pressure were observed following fentanyl administration. Distribution and clearance data were similar to those reported for dogs and humans.

Analgesics, Opioid↗
PubMed2004

Investigation of in vitro transdermal absorption of fentanyl from patches placed on skin samples obtained from various anatomic regions of dogs.

OBJECTIVE: To investigate in vitro transdermal absorption of fentanyl from patches through skin samples obtained from various anatomic regions of dogs. SAMPLE POPULATION: Skin samples from 5 Greyhounds. PROCEDURE: Skin samples from the dogs' thoracic, neck, and groin regions were collected postmortem and frozen. After samples were thawed, circular sections were cut and placed in Franz-type diffusion cells in a water bath (32 degrees C). A commercial fentanyl patch, attached to an acetate strip with a circular hole, was applied to each skin sample. Cellulose strips were used as control membranes. Samples of receptor fluid in the diffusion cells were collected at intervals for 48 hours, and fentanyl concentrations were analyzed by use of high-performance liquid chromatography. RESULTS: Mean+/-SD release rate of fentanyl from the patch, defined by its absorption rate through the non-rate-limiting cellulose membrane, was linear during the first 8 hours (2.01+/-0.05 microg/cm2 of cellulose membrane/h) and then decreased. Fentanyl passed through skin from the groin region at a faster rate and with a significantly shorter lag time, compared with findings in neck or thoracic skin samples. CONCLUSIONS AND CLINICAL RELEVANCE: In vitro, fentanyl from a patch was absorbed more quickly and to a greater extent through skin collected from the groin region of dogs, compared with skin samples from the thoracic and neck regions. Placement of fentanyl patches in the groin region of dogs may decrease the lag time to achieve analgesia perioperatively; however, in vivo studies are necessary to confirm these findings.

Administration, Cutaneous↗
PubMed1994

Inhalation abuse of fentanyl patch.

A 36-year-old male became intoxicated from fentanyl by heating and inhaling the contents from a fentanyl patch. He collapsed immediately after one inhalation with a respiratory rate of 6/m, heart rate of 120 bpm, and unobtainable blood pressure. He responded to a naloxone injection. Inhalation abuse of fentanyl base is a novel phenomenon. In two studies of nebulized fentanyl at doses of 64-318 micrograms of fentanyl base, analgesia was achieved with these doses, and small decreases in respiratory rate occurred with the larger dose. The greater absorption expected from inhaling the volatilized product, the large quantity of fentanyl available in a patch, and the high potency of fentanyl produces a high potential for abuse and overdose.

Administration, Inhalation↗
PubMed1999

Negative chronotropic effects of fentanyl attenuate beneficial effects of dobutamine on oxygen metabolism: hemodynamic and pharmacokinetic interactions.

Opioids are well known to cause cardiovascular depression. The aim of the present investigation was to determine whether an interaction of opioid derivatives with catecholamines might be involved in these hemodynamic alterations. Six comatose patients were enrolled into a prospective, nonrandomized pilot trial. All patients first received a continuous i.v. infusion of dobutamine (10 microgram. kg-1. min-1) paralleled by continuous administration of midazolam (0.4 mg. kg-1. h-1); thereafter, fentanyl was added i.v. (4 microgram. kg-1. h-1). Hemodynamic parameters as well as dobutamine and endogenous catecholamines plasma levels were determined. The mean arterial blood pressure did not change significantly during the whole study period. The continuous administration of dobutamine (steady-state plasma concentrations: 217 +/- 118 ng. ml-1) increased the beta1-adrenergic receptor-mediated hemodynamic parameters such as heart rate, stroke volume index, cardiac index, and oxygen delivery index (p <.05). The concomitant administration of fentanyl decreased the heart rate-dependent hemodynamic parameters (p <.05), suggesting that fentanyl antagonizes the chronotropic effects of dobutamine. In parallel, dobutamine plasma levels increased significantly (275 +/- 165 ng. ml-1; p <.05). Noteworthy, after administration of fentanyl, oxygen delivery and consumption index returned to baseline values. Radioligand binding experiments on rat cardiac ventricular microsomes ruled out a direct interaction of fentanyl with beta-adrenergic receptors and, more importantly, a fentanyl-induced inhibition of beta-adrenergic receptor G protein coupling. Our observations suggest that fentanyl inhibits the frequency-related hemodynamic changes induced by dobutamine. The underlying mechanism is independent of beta-adrenergic receptors, but is powerful enough to abolish the salutary effect of dobutamine on oxygen delivery and consumption.

Aged↗
PubMed2001

Evaluation of a transdermal fentanyl system in yucatan miniature pigs.

Of 18 pigs used on a coronary stent experimental protocol, 6 each received a transdermal fentanyl patch to document the patterns of transdermal fentanyl absorption in swine. This approach was taken to reduce animal use and potentially refine the surgical regimen. The objective of the fentanyl portion of the study was to demonstrate that transdermal fentanyl may be useful in the management of postoperative analgesia in swine. This study sought to document that demonstrable levels of fentanyl are achievable in swine plasma via a transdermal system and to compare the magnitude of these levels to data in other species. This study does not directly correlate plasma fentanyl levels with analgesic efficacy. Plasma fentanyl concentration peaked within 42 h in five pigs and within 48 h in the remaining pig. All pigs had similar absorption patterns; the only difference was in magnitude. One pig reached 0.99 ng/ml at 42 h; the next highest concentration was 0.77 ng/ml at 48 h in a different animal. The peak concentration in the others ranged from 0.38 to 0.71 ng/ml.

Administration, Cutaneous↗
PubMed1975

Cardiopulmonary effects of fentanyl-droperidol, nitrous oxide, and atropine sulfate in dogs.

The cardiopulmonary effects of droperidol-fentanyl, nitrous oxide, and atropine were evaluated in 12 adult male Beagle dogs. All dogs were surgically instrumented with a cardiac output thermistor and arterial and venous catheters and were prepared with a chronic tracheostomy. Each dog was used as its own control, and data obtained when dogs were nonanesthetized and nonmedicated were compared with data recorded after the test drugs were administered. The dogs were randomly allotted to 3 groups of 4 dogs each. Group I dogs were given droperidol-fentanyl alone intravenously (IV); group II dogs were given droperidol-fentanyl IV with 67% nitrous oxide; and group III dogs were given atropine sulfate intramuscularly followed by droperidol-fentanyl IV with 67% nitrous oxide. Minute volume was decreased in the 3 groups of dogs for 3 to 5 minutes after droperidol-fentanyl was injected. This resulted in respiratory and metabolic acidosis in all dogs, as indicated by increased arterial carbon dioxide tension, decreased pH, and increased base deficit. In addition, droperidol-fentanyl given alone caused a decrease in systolic pressure and a slight decrease in heart rate. Group 1 dogs were sensitive to auditory stimulation. Cardiovascular changes were not seen when nitrous oxide was added; however, analgesia and muscle relaxation were improved. Premedication with atropine sulfate resulted in increased cardiac output, heart rate, and diastolic pressure, and subsequent administration of droperidol-fentanyl with nitrous oxide caused a transient increase in mean arterial and systolic pressure. This last anesthetic regimen, along with assisted or controlled respiration, seems to provide an excellent anesthetic state with minimal cardiopulmonary depression.

Analgesia↗
PubMed2001

Implementing sevoflurane anesthesia with small doses opioid for upper abdominal surgery. Postoperative respiratory function after either remifentanil or fentanyl.

BACKGROUND: The aim of this prospective, randomized study was to compare the effects on intraoperative cardiovascular homeostasis, recovery profile and postoperative oxygen saturation after sevoflurane anesthesia with small doses of either remifentanil or fentanyl in combination with postoperative epidural analgesia. METHODS: With Ethical Committee approval and written patient consent, 30 ASA physical status I-II patients scheduled for elective upper abdominal surgery were randomly allocated to receive sevoflurane general anesthesia implemented with small doses of either remifentanil (n = 15) or fentanyl (n = 15), followed by postoperative epidural analgesia. Remifentanil group patients received a 1 mg kg-1 bolus infused during a 60 sec period followed by a 0.15 mg kg-1 min-1 infusion; while patients of Fentanyl group were given a 3 mg kg-1 initial dose followed by 50 mg boluses as requested (according to the time to peak effect of the two drugs, the initial dose was given 5 min before induction in Fentanyl group, and 1 min before induction in Remifentanil group). Postoperatively, oxygen saturation was continuously recorded and stored on a computer during the first 12 h after surgery. SpO2 decrease < 90% for more than one minute was considered as a minor respiratory complication. RESULTS: The median sevoflurane's MAC-hour was 2.7 (1.4 - 4.9) in patients receiving remifentanil infusion and 4.1 (2.2 - 5.7) in those patients receiving fentanyl during surgery (P = 0.005). However, no differences in the recovery times were observed between the two groups. Similar pain relief was reported during coughing in the two studied groups at discharge from the recovery area and during the following study period. No major respiratory complication was observed throughout the study. Oxygen therapy was required in three patients of Fentanyl group only 20% (P = 0.22); however, 11 patients in the same group (73%) showed at least one minor respiratory complication (SpO2 < 90% for more than 1 min), with a median of 1 (range 0 - 12) episode per patient, compared with no episode in Remifentanil group (P = 0.0005). CONCLUSIONS: Implementing sevoflurane anesthesia with very small remifentanil infusion provides a safe and effective hemodynamic control reducing sevoflurane consumption during the procedure, and produces less respiratory effects postoperatively as compared with intermittent bolus administration of fentanyl.

Abdomen↗
PubMed2002

[Effects of preincisional epidural administration of lidocaine and fentanyl on postoperative pain management following hysterectomy].

OBJECTIVE: To compare the effect of preincisional administration different combination of epidural lidocaine and fentanyl on postoperative analgesia after hysterectomy. METHODS: 75 ASA I-II patients undergoing hysterectomy who were matched in age, weight, and duration of surgical procedure, were randomly allocated to one of the three treatment groups, 25 in each: group I receiving epidural saline as control, group II receiving epidural 2% lidocaine 10 ml combined with 2.5 microg/ml of fentanyl 30 minutes before skin incision followed by 0.125% ropivacaine and 2 microg/ml fentanyl infusion at 9ml/h to the end of surgery, and group III receiving epidural 2% lidocaine 10 ml combined with 2.5 microg/ml of fentanyl and 0.15 mg/ml of droperidol 30 min before incision followed by 0.125% ropivacaine and 2 microg/ml fentanyl infusion at 9ml/h to the end of surgery. Patient-controlled epidural analgesia (0.125% ropivacaine and 2 microg/ml fentanyl.) was given for postoperative pain relief in all groups (5 ml bolus followed by 3 ml/h infusion, PCA dose: 2 ml, lock out time: 10 min.). Postoperative pain intensity at rest and during movement was assessed on a visual analogue scale (VAS) by a blinded observer for 48 h after surgery. Analgesic requirements and side effects were compared among the three groups. RESULTS: In the first 24 hours after surgery, the VAS score at rest reported by the patients in group I was 2.2 +/- 1.5, significantly higher than that in group II (1.4 +/- 0.8, P < 0.05,) and that in group III (1.1 +/- 1.1, P < 0.01), while the VAS score during coughing in group I was 3.0 +/- 1.1, higher than that in group II (2.1 +/- 0.8) and that in group III (1.5 + 1.3,P < 0.01 ). Analgesic requirements in the first 24 hours were 101 +/- 17 ml in group I, 82 +/-9 ml in group II, and 78 ml +/- 9 ml in group III, without significant difference among the groups. However, the analgesic requirement in the second 24 hours was 82 +/- 11 ml in group I, much more than that in group II (76 +/- 5 ml, P < 0.05) and in group III (73 ml +/- 2 ml, P < 0.01). The incidence of nausea, was significantly higher in Group I than in group III (P < 0.05). The incidence rates of pruritus and motor block were higher in group I too. CONCLUSION: The preoperative administration of epidural lidocaine and small dose of fentanyl with droperidol, compared with saline administration, improves the postoperative pain management and reduces postoperative analgesic consumption and side effects.

Adult↗
PubMed2000

[Effects of urapidil on cardiovascular response to tracheal intubation and incision during fentanyl co-induction].

To study the effects of urapidil (URA) on cardiovascular response to tracheal intubation and incision during fentanyl co-induction, forty-two patients (ASA I-II) were randomly divided into four groups: Group F1(n = 10), fentanyl 5 micrograms.kg-1 was given by venous injection; Group F2(n = 10), fentanyl 10 micrograms.kg-1; Group U1(n = 10), URA 0.25 mg.kg-1 plus fentanyl 5 micrograms.kg-1; Group U2(n = 12), URA 0.5 mg.kg-1 plus fentanyl 5 micrograms.kg-1. After tracheal intubation, mean arterial pressure (MAP), diastolic pressure (DP) in Group F1 and systolic pressure (SP) in Group U1 were increased more significantly than those in Group U2(P < 0.05). After incision, the values of SP, MAP, DP and rate-pressure product (RPP) in Group F1 were higher apparently than those in Group U2(P < 0.05); at the 5th minute, SP, MAP, heart rate (HR) and RPP in Group F1 were in higher than those in Group F2 (P < 0.05), and SP, MAP in Group U2 were lower than those in Group U1(P < 0.05). It is suggested that the cardiovascular response to tracheal intubation and incision may be effectively inhibited in combination URA with fentanyl, and the dosage of fentanyl might reduce.

Anesthetics, Intravenous↗
PubMed1992

[The efficacy of intravenous fentanyl patient-controlled analgesia for postoperative pain relief].

The safety and efficacy of patient-controlled analgesia used for postoperative pain relief were evaluated. Cumulative 24-hour requirements were analyzed for possible correlation with patient characteristics. All patients who used a patient-controlled analgesia device for postoperative pain relief were reviewed from June to October 1991. The device Baxter's basal/bolus infusor with patient control module, was used to deliver fentanyl in 379 patients. The fentanyl requirement, verbal analog pain score, first passage of flatus, side effects, sedative score, and degree of satisfaction were examined. The fentanyl requirement during the first 24 hours after operation was analyzed with regard to age, body weight, and sex. The daily fentanyl consumption in the first three postoperative days was 928 +/- 352 micrograms (n = 338), 553 +/- 259 micrograms (n = 220), and 490 +/- 222 micrograms (n = 71), respectively. The requirement for fentanyl during the first 24 hours after surgery was significantly higher than for the next two days (p-value < 0.001). Fentanyl consumption correlated well with body weight, and inversely with age. No difference was found between fentanyl consumption and sex (p-value = 0.4687). The mean time to the first passage of flatus in patients with abdominal surgery was 54.6 +/- 26.4 hours. The incidence of nausea, vomiting, and dizziness was similar, about 20% of patients. Itching was noted in 7% of patients. Oversedation (class 4) was found in three patients during the first operative day, the sedative score for other patients were around class 1-3. No patient exhibited signs of respiratory depression or withdrawal syndrome.(ABSTRACT TRUNCATED AT 250 WORDS)

Abdomen↗
PubMed2004

Deaths after intravenous misuse of transdermal fentanyl.

Fentanyl is a potent synthetic opioid used as a general anesthetic and analgetic. Fatal outcome from intravenous misuse of transdermal fentanyl is rare, and there are few such reports in literature. Here we report two cases of fatal intravenous injection of the content from fentanyl patches. Both were male drug addicts, found dead within a one week interval in the same apartment. Post-mortem femoral blood was screened for amphetamines, cannabinoids, cocaine, and opioids with immunological methods (EMIT II) and further with headspace gas chromatography for alcohol and with liquid chromatography mass spectrometry (LC-MS) for different drugs, including fentanyl. Confirmatory analysis of fentanyl and morphine was performed by gas chromatography-mass spectrometry (GC-MS). In the first case, the toxicological analysis revealed fentanyl (2.7 ng/mL), morphine (31.4 ng/mL), and ethanol (1.1 g/L) in postmortem blood and amphetamine, cannabinoids, morphine, and ethanol (1.4 g/L) in postmortem urine. In the second case, the analysis revealed fentanyl (13.8 ng/mL), 7-aminoclonazepam (57.1 ng/mL), and sertralin (91.9 ng/mL) in postmortem blood and a small amount of ethanol (0.1 g/L) in postmortem urine. Police investigation revealed that both the deceased had bought the patches from the same source. The present cases demonstrate the possibility of intravenous misuse of transdermal patches and the risk of fatal outcome.

Administration, Cutaneous↗
PubMed2005

[Postoperative pain management using subcutaneous fentanyl and ketamine after abdominal gynecologic surgery].

BACKGROUND: Subcutaneous opioid is one way of managing postoperative pain in patients undergoing anticoagulant therapy. We have evaluated the safety and the efficacy of postoperative pain management using subcutaneous fentanyl and ketamine after abdominal gynecologic surgery. METHODS: Written informed consent was obtained from 50 ASA physical status 1 or 2 female patients aged between 20 and 65. Patients were randomized to one of 5 groups. Group 1, 2 and 3 received 25, 35 and 50 microg x h(-1) subcutaneous fentanyl infusion, respectively. Group 4 received 25 microg x h(-1) fentanyl and 2 mg x h(-1) ketamine subcutaneously; group 5 received 25 microg x h(-1) fentanyl and 4 mg x h(-1) ketamine subcutaneously. General anesthesia was administered to all patients. Two hours after induction, subcutaneous infusion of fentanyl and ketamine was started in the patients and discontinued 24 hours after the operation. All patients were assessed twice, at 4 hours and at 24 hours after operation. Blood gas analysis was performed. Number of analgesic administration required during the 24 hours after operation was recorded. Groups 1, 2, 3 and groups 1, 4, 5 were evaluated as one group, respectively. Group differences were analyzed by variance analysis. Differences of analgesic administration were analyzed with Kruskal-Wallis test. RESULTS: As to anesthetic requirement during the 24 hours after operation, there were no significant differences among treatment groups. With respect to blood gas analysis, only individuals receiving subcutaneous 25 microg x h(-1) fentanyl and 4 mg x h(-1) ketamine maintained high PaO2 4 hours after the operation (P<0.05). CONCLUSIONS: We recommend administration of 25 microg x h(-1) fentanyl and 4 mg x h(-1) ketamine subcutaneously, which maintains high Pao2 and requires less analgesic.

Adult↗
PubMed2006

[Low-dose ketamine combined with fentanyl for intravenous postoperative analgesia in elderly patients].

OBJECTIVE: To investigate the clinical efficacy of and complications arising from low-dose ketamine combined with fentanyl for intravenous postoperative analgesia in comparison with the exclusive use of fentanyl in elderly patients. METHODS: Eighty elderly patients were randomized into two equal groups following thoracoabdominal surgery, and received intravenous analgesia with the combination of 0.5 mg/ml ketamine, 5.0 microg/ml fentanyl and 50 microg/ml midazolam (KF group) and with 7.5 microg/ml fentanyl plus 50 microg/ml midazolam (FT group), respectively. The drugs used were diluted in 200 ml normal saline. For analgesic administration, a loading dose (2-4 ml) was given followed by a background infusion (2.5-3.5 ml), with patient-controlled bolus doses of 2.0-3.0 ml with lock-out time of 20 min via PCA pump (Automedical, Korea). The static pain score (VAS), sedation score, and incidences of nausea, vomiting, pruritus and hallucinations were recorded during the initial 48 h after the surgery. RESULTS: The total analgesic dosage and PCA dosage in the two groups were similar (P>0.05). With similar VAS in the two groups (P>0.05), the sedative effect in KF group was much better than that in FT group (P<0.05) during the initial 48 h postoperatively. The incidences of nausea, vomiting and itching were lower in KF group than in FT group (P<0.05), and no illusion was reported in two groups during the initial 48 h. CONCLUSION: For producing comparable postoperative analgesic effect, low-dose ketamine combined with fentanyl can markedly reduce fentanyl requirement in the elderly patients and lowers the incidences of nausea, vomiting and itching in comparison with the exclusive use of fentanyl.

Aged↗
PubMed1991

Clinical uses of fentanyl, sufentanil, and alfentanil.

The pharmacokinetics, pharmacodynamics, and clinical uses of fentanyl, sufentanil, and alfentanil are reviewed. The fentanyl derivatives have reduced or eliminated many of the disadvantages of opioid anesthetics, such as incomplete amnesia and undesirable hemodynamic responses to surgery. Fentanyl is 50-100 times as potent as morphine and was the first of the three to be marketed. Sufentanil is even more potent than fentanyl. Alfentanil has the fastest onset of action, followed by sufentanil and then fentanyl. Alfentanil also has the shortest duration of action of the group. Most studies of these agents have been done to assess their role as anesthetics in cardiac surgery. All three provide cardiovascular stability when administered before noxious surgical stimuli, except when given as a single bolus during the induction of anesthesia. All seem to produce adequate anesthesia, particularly when used in combination with nitrous oxide. Because of its short duration of action, alfentanil is preferred for brief procedures or when rapid changes in the level of consciousness are desired. All three agents have also been used for analgesia; epidural administration provides adequate relief of pain. Fentanyl has been formulated as a transdermal patch that seems to provide the same degree of analgesia as a continuous i.v. infusion. Fentanyl has also been formulated as an investigational lozenge that has shown advantages as a preoperative sedative in children. As more is learned about these agents, their perioperative uses for anesthesia, analgesia, and sedation will continue to be refined.

Absorption↗
PubMedDate not supplied

The effect of fentanyl, meperidine and diamorphine on nerve conduction in vitro.

The effect of fentanyl, meperidine and diamorphine on A- and C-fiber conduction in an in vitro rabbit vagus nerve preparation was examined. The nerves were maintained at 37 degrees C with an oxygenated electrolyte solution. The effect of the commercial preparation of fentanyl (Sublimaze) and isotonic solutions of fentanyl, meperidine and diamorphine were observed. Sublimaze had a neurotoxic effect related to its hypotonicity. In isotonic solutions, fentanyl and meperidine, but not diamorphine, blocked nerve conduction and both showed marked frequency-dependent blocking actions in C-fibers. Naloxone (Narcan) did not prevent the effect of fentanyl. Both fentanyl and meperidine potentiated the block produced by a low concentration of bupivacaine (0.005 mM, 0.00016%), the effect of meperidine being seen at clinically relevant concentrations. Fentanyl was slightly more potent than meperidine in its effect on nerve conduction, but its greater opioid potency would not allow its use as a local anesthetic. The local anesthetic effect of meperidine may be more useful clinically.

Animals↗