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PubMed2005

[Effects of fentanyl on cytokines and MDA during cardiopulmonary bypass in patients undergoing valve replacement].

OBJECTIVE: To investigate the effect of fentanyl on cytokines and MDA in valve replacement surgery during cardiopulmonary bypass ( CPB). METHODS: Thirty ASA II approximately III adult patients scheduled for cardial valve replacement were randomly divided into 3 groups: Group A (fentanyl 30 microg/ kg), Group B (fentanyl 60 microg/kg), and Group C (fentanyl 100 microg/kg). Anesthesia was induced with medazalam 0.1 mg/kg, fentanyl 10 microg/kg and vecuronium 0.1 mg/kg Administered intravenously. After tracheal intubation the patients were mechanically ventilated with pure oxygen. P(ET)CO2 was maintained between 35 approximately 45 mmHg. Anesthesia were maintained with fentanyl infusion combined with intermittent intravenous bolus of midazolam and vecuronium. MAP, CVP, HR, P(ET)CO2, SPO2, nasal and rectal temperature were monitored continuously. Remained dose of fentanyl was infused before the CPB. Blood Samples were taken before the operation (T1 ), before the CPB ( T2 ), 30 min after aortic declamping (T3 ) , 2 h after aortic declamping (T4 ), and 24 h (T5 ) after the operation for determination of plasma levels of tumor necrosis factor (TNF-alpha), interteukin IL-6 and IL-10, MDA. RESULTS: There was no significant change in the age, body weight, aortic cross-clomp time, CPB time, and operation time. Levels of TNF-alpha, IL-6, IL-10 and MDA after the CPB in the 3 groups were significantly higher compared with T, (P <0.01 ), TNF-alpha, IL-6 and MDA levels at T3, T4 were significantly lower in Group B and C than those in Group A. IL-10 levels at T4, T5 were significantly higher in Group B and C than those in Group A, but levels of TNF-alpha, IL-6, IL-10 and MDA in Group B were not significantly different compared with those in Group C. The duration of stay in the ICU and time of endotracheal extubation were significantly longer in patients of Group C than those of Group A and B. CONCLUSION: CPB leads to a proinflammatory and antiinflammatory response, as well as oxygen free radicals release. Larger dose fentanyl seemed to be effective in reducing CPB-induced inflammatory response and ischemic reperfusion injury, but the effect was not dependent on dose while fentanyl dose reaching some value, at the same time the duration of stay in ICU and time of endotracheal extubation is longer.

Anesthetics, Intravenous↗
PubMed2005

Inter- and intra-individual variability in transdermal fentanyl absorption in cancer pain patients.

A transdermal therapeutic system (TTS) is recommended for use in chronic cancer pain, particularly in the advanced stages. The aim of this trial was to study intra- and interindividual variabilities in fentanyl transdermal absorption and investigate physiological and clinical parameters that can influence the absorption in patients treated using a TTS for moderate to severe cancer pain. The study group consisted of 108 patients (71 men and 37 women; mean age, 61.3 years) with chronic cancer pain. A total of 507 patches were analysed. The TTSs used to administer fentanyl were removed after a 72-h period. The amount of fentanyl remaining in the patches was determined using a high-performance liquid chromatography method with ultraviolet detection. Depending on the analgesic requirements of the patient, the dose of fentanyl administered by TTS ranged from 25 to 500 microg/h. The study period was 6 months. Large interindividual variability in the amount of remaining fentanyl in the patches occurred. For 58.1% of patches, absorption was 60 to 84%; for 33.2% of them, it was lower; and for 8.8%, it was higher than this range. The intra-individual variability ranged from 2.8 to 75.1%. The bioavailability of fentanyl was statistically different according to patient age. Patients >75 years of age absorbed 50% of the fentanyl during the selected 72-h period, whereas patients <65 years absorbed 66%. Moreover, there is a significant difference in the percentage of absorbed fentanyl according to the type of cancer. The absorption was higher in patients with breast or digestive cancer than in those with lung cancer. Hyperhidrosis, hypertrichosis and the localization of patches on the skin did not influence bioavailability. For the entire group, transdermal fentanyl treatment provided good to excellent pain relief in the majority of patients.

Administration, Cutaneous↗
PubMed2006

[Fentanyl shows different effects by administration routes on bispectral index during spinal anesthesia in patients undergoing cesarean section].

BACKGROUND: Spinal anesthesia using a local anesthetic with fentanyl has been reported to induce sedation. We previously reported that the bispectral index (BIS) value was significantly decreased by spinal anesthesia using only bupivacaine and fetanyl after cesarean delivery. In the present study, we studied the effect of different fentanyl administration routes on BIS values during spinal anesthesia for cesarean section. METHODS: Forty-six women scheduled for cesarean section were allocated into five-groups according to the route of fentanyl administration and amount of local anesthetic: intrathecal 0.5% isobaric bupivacaine 2.5 ml plus fentanyl 20 microg (n = 11), intrathecal 0.5% isobaric bupivacaine 2.5 ml plus intravenous fentanyl 100 microg (n = 12), intrathecal 0.5% isobaric bupivacaine 2.5 ml plus epidural fentanyl 100 microg (n = 8), intrathecal 0.5% isobaric bupivacaine 2.5 ml (n = 8), and intrathecal 0.5% isobaric bupivacaine 3.0 ml (n = 7). BIS values were recorded during anesthesia. RESULTS: BIS values in intrathecal fentanyl group were lower than those of other groups (P = 0.03). The cumulative duration of BIS values 80 and below 80 was longer in the intrathecal fentanyl group than those of other groups (P = 0.004). CONCLUSION: The BIS value was significantly decreased only by intrathecal fentanyl for cesarean section.

Adult↗
PubMedDate not supplied

[The effect of fentanyl as an adjuvant to etomidate and thiopental on the hemodynamic response to the induction of anesthesia and endotracheal intubation].

The hemodynamic modifications during anesthesia induction with etomidat or thiopentalum, with and without pretreatment with fentanyl, were studied in 60 ASA I-II patients. The patients were randomly divided into six subgroups, as a function of the induction agent (etomidat, 0.15 mg/kg, or thiopentalum, 3 mg/kg) and of the pretreatment used (fentanyl, 5 micrograms/kg, or 0.9% 1 ml/kg saline solution). Systolic, diastolic ATs and pulse were followed and measured during induction and after tracheal intubation. During induction the presence or absence of the thoracic rigidity, after fentanyl administration, and also the appearance of myoclonias and of local pain after etomidat injection were noted. Measurement of hemodynamic constants showed, in the control subgroups unprotected by fentanyl, that AT and pulse frequency increase following laryngoscopy and intubation irrespective of the induction agent used. Association of thiopentalum with fentanyl influenced partially tachycardia and postintubation hypertension. Administration of 5 micrograms/kg fentanyl prevented the SAT and pulse modifications but not the DAT variation. Association of 10 micrograms/kg fentanyl ensured a complete protective effect versus the tracheal intubation but, it led, first, to a SAT decrease by intensification of the myocardial depressing effect of the barbiturate. On the other hand, use of fentanyl as induction adjuvant with etomidat ensured the blockage of the pressure response to intubation, with hemodynamic stability during anesthesia induction, irrespective of the dose of fentanyl injected. Thoracic rigidity and the side effects generated by etomidate were absent.

Anesthesia, General↗
PubMed1989

[Intrathecal clonidine--how does it work in spinal fentanyl analgesia in rats?].

The effects of intrathecal clonidine on spinal fentanyl analgesia were studied by the hot-plate test (52.0 degrees C) in rats. Clonidine (5 micrograms) and/or fentanyl (5 micrograms) were administered alone or combined in volume of 10 microliters through a chronically-implanted polyethylene catheter (PE-10) whose tip was near the lumbar enlargement of the spinal cord. Injections were done repeatedly every two or three days to determine the time course of thermal analgesia. Results were as follows; 1) Intrathecal clonidine (n = 5) produced no thermal analgesia. 2) Intrathecal fentanyl (n = 10) produced a profound thermal analgesia which was attenuated markedly by the repeated injections in six rats before the 9th injection. 3) Two out of six fentanyl tolerated rats responded with remarkable increases in thermal thresholds following the intrathecal clonidine with fentanyl. 4) Rats which were administered with both clonidine and fentanyl from the 1st injection (n = 9) responded with a extended prolongation of the escape latency, compared with the rats which received fentanyl only. In this group, the tolerance developed in only three animals by the 9th injection. In conclusion, combined intrathecal administration of clonidine with fentanyl potentiated the analgesic effect of fentanyl and then definitely suppressed the tolerance formation even if a small dose of clonidine which produces no analgesic effect was used. These results suggest that intrathecal or epidural administration of clonidine with narcotics might be useful in managing intractable pain.

Adaptation, Physiological↗
PubMed1986

High-sensitivity radioimmunoassay screening method for fentanyl.

A radioiodinated analog of fentanyl was synthesized for use with a commercially available radioimmunoassay for fentanyl. The sensitivity of the modified assay was at least 100 times greater than that of the original assay. Using this modified assay, concentrations of fentanyl as low as 1 pg/ml of fentanyl or fentanyl equivalents in equine urine were detected. Doses of fentanyl 100 times smaller than the minimum dose for a pharmacologic effect were detectable and a pharmacologically effective dose of fentanyl was detectable for up to 96 hours or more. The high sensitivity of the assay indicated that large numbers of urine samples (ie, 10 to 20) probably could be pooled and screened simultaneously, which would result in an economical analysis for fentanyl in the urine of horses after a race. Sufentanil and its metabolites also were detectable, using this assay, but at only about 1% of the efficiency at which fentanyl was detectable.

Animals↗
PubMed1987

Is fentanyl an anesthetic in the dog?

The authors used the absence of vocalization and movement during application of a hemostat clamped to the first ratchet at the base of the tail as an indication of anesthesia for evaluation of the anesthetic properties of fentanyl in the dog. Eighty-six unpremedicated, unrestrained, untrained mongrel dogs were given one of eight doses of fentanyl citrate (125, 250, 500, 750, 1000, 1500, 2000, and 3000 micrograms/kg) as a single intravenous bolus injection. Dogs breathed spontaneously without oxygen supplementation. Anesthesia was assessed every 5 min until absence of anesthesia was recorded for two consecutive evaluations. Venous plasma samples were obtained in two or three dogs receiving each of the doses of fentanyl 5 min after fentanyl injection and again when application of the tail clamp elicited either vocalization or movement (positive response). Fentanyl resulted in recumbency in all animals except two receiving 125 micrograms/kg. Although all doses of fentanyl produced anesthesia in at least one animal 5 min after injection, the duration of anesthesia was short, responses unpredictable, and anesthesia achieved in all animals only with a dose of 3000 micrograms/kg. Increasing doses of fentanyl resulted in higher plasma fentanyl concentrations 5 min after injection and at the time of the first positive response to tail clamp but there was great variability. All doses of fentanyl caused statistically significant decreases in heart and respiratory rates but none produced apnea or a PaCO2 higher than 67 mm Hg.(ABSTRACT TRUNCATED AT 250 WORDS)

Anesthesia, Intravenous↗
PubMedDate not supplied

Cardiovascular effects of fentanyl during enflurane anesthesia in man.

The cardiovascular effects of three doses of intravenous fentanyl (50, 100, and 200 microgram) were determined in 42 adult patients undergoing intraabdominal surgical procedures with enflurane (2--3%) and nitrous oxide (50%) in oxygen. Fentanyl was administered a minimum of 40 minutes after induction of anesthesia and 30 minutes after initiation of the surgical procedure. Stroke volume, heart rate, cardiac output, mean arterial and central venous blood pressures, and peripheral arterial resistance were determined by computer analysis of the central aortic pulse-pressure curve according to the method of Warner. Measurements were made before and 2, 4, 6, 8, and 10 minutes after fentanyl. Fentanyl (50 microgram) produced increases in stroke volume and cardiac output as well as a decrease in peripheral arterial resistance but did not alter heart rate or mean arterial blood pressure. Fentanyl (100 microgram) did not significantly change any variable at any time. Fentanyl (1l (200 microgram) produced sustained decreases in stroke volume, cardiac output and mean arterial blood pressure and increased central venous pressure but did not alter heart rate or peripheral arterial resistance. The data indicate that fentanyl (50--100 microgram) stimulates or has no effect on cardiovascular dynamics during enflurane-nitrous oxide anesthesia but fentanyl (200 microgram) produces significant cardiovascular depression. Our findings suggest that small doses of intravenous fentanyl may be of benefit during enflurane-nitrous oxide but larger doses should probably be avoided.

Adult↗
PubMed1984

Fentanyl preloading for rapid-sequence induction of anesthesia.

Protecting the patient's airway is of paramount importance in the induction of general anesthesia. For the patient at risk of regurgitation of stomach contents, the rapid-sequence (crash) induction provides protection, but at the expense of increased stress response to laryngoscopy and intubation. This stress response is especially dangerous for the patient at risk for myocardial ischemia. The purpose of this study was to examine the efficacy of using low-dose fentanyl (5 micrograms/kg) to reduce cardiovascular and neuroendocrine stress responses to rapid-sequence induction. Thirty patients were randomly assigned to a rapid-sequence induction protocol either with or without fentanyl preloading. Fentanyl-preloaded patients (fentanyl group) received 2 mg/kg of thiopental whereas patients who were not preloaded with fentanyl (control group) received 4 mg/kg of thiopental. Data collected as indices of the stress response included heart rate, systolic, diastolic, and mean blood pressures, and plasma concentrations of catecholamines (epinephrine, norepinephrine, dopamine) and beta-endorphin. Electrocardiograms (modified V5 lead) were monitored for dysrhythmias and ST segment depression. Control patients had higher systolic, diastolic, and mean blood pressures after intubation than did patients given fentanyl (P less than 0.05). Although the incidence of dysrhythmias was decreased by fentanyl (20% vs 42%), this difference was not statistically significant. Plasma concentrations of beta-endorphin and norepinephrine increased significantly in control patients but not in patients given fentanyl (P less than 0.05). Low-dose fentanyl (5 micrograms/kg) reduces some aspects of the stress response to rapid-sequence induction of anesthesia.

Adult↗
PubMedDate not supplied

Epidural clonidine decreases postoperative requirements for epidural fentanyl.

OBJECTIVE: This study assesses the possibility that clonidine may decrease analgesic opioid demand in postoperative patients. METHODS: Twenty-five patients were allocated randomly after abdominal surgery to receive either an epidural bolus dose of fentanyl (1.0 mcg.kg-1) followed by a 1.0 mcg.kg-1h-1 continuous epidural infusion, or an epidural bolus dose of fentanyl (1.0 mcg.kg-1) followed by a continuous epidural infusion combining fentanyl 0.5 mcg.kg-1 x h-1 and clonidine 0.3 mcg.kg-1 x h-1. Pain was assessed at definite intervals on a visual analog scale (VAS) over 3 postoperative days. Epidural infusion was halved when VAS score was lower than 2. Patients were monitored with a pulse oximeter over 12 hours during the first postoperative night. Plasma fentanyl was measured by radioimmunoassay when patients left the recovery room and at 8 a.m. on the first and the second postoperative days. RESULTS: VAS scores were comparable in the two groups of patients. The amount of fentanyl delivered was significantly lower in the fentanyl + clonidine group, as were the plasma fentanyl concentrations. The duration of SaO2 < 90% episodes was significantly less prolonged in the fentanyl + clonidine group (3.5 +/- 4.8 minutes versus 14.4 +/- 14.6 minutes). CONCLUSIONS: The combination of clonidine to epidural fentanyl allows a decrease in opioid requirements without impairing analgesia. Reduction of opioids administration may have beneficial effects on respiratory function in postoperative patients.

Abdomen↗
PubMed1993

Plasma fentanyl levels in infants undergoing extracorporeal membrane oxygenation.

Plasma levels of fentanyl were analyzed in 12 infants undergoing extracorporeal membrane oxygenation who received a fentanyl bolus (5 to 10 micrograms/kg) followed by infusion at 1 to 6.3 micrograms/kg/hr. Fentanyl levels, averaging 11 samples/infant, were measured by radioimmunoassay (mean 19.7 +/- 35.7 ng/ml; n = 140). Eight of the infants, all with a primary diagnosis other than congenital diaphragmatic hernia, survived with relatively short (< 7 days) courses on extracorporeal membrane oxygenation; this group of infants did not develop tolerance to fentanyl and could be maintained on infusion rates of < 5 micrograms/kg/hr throughout. The four infants with congenital diaphragmatic hernia had longer extracorporeal membrane oxygenation runs and three did not survive; their plasma fentanyl levels were consistently higher and while the infusion rates were higher early on extracorporeal membrane oxygenation, they did not exceed 7 micrograms/kg/hr and actually decreased after 5 days on extracorporeal membrane oxygenation. Five infants (42%) received lorazepam in addition to fentanyl for at least one sampling time. The fentanyl infusion dose and plasma level were higher in the congenital diaphragmatic hernia nonsurvivors who did not receive lorazepam (p < 0.001). A decrease in fentanyl clearance correlated with renal dysfunction (p < 0.01). A bolus of fentanyl followed by infusion of relatively low doses (1 to 5 micrograms/kg/hr) provides adequate analgesia for infants on extracorporeal membrane oxygenation, particularly when it is supplemented with intravenous lorazepam whenever needed to control infant movement.

Analgesia↗
PubMed1996

Effects of diazepam on fentanyl-induced epileptoid EEG activity and increase of multineuronal firing in limbic and mesencephalic brain structures.

Electroencephalographic and clinical signs of epileptoid activity have been associated with the administration of fentanyl during surgery in patients. These phenomena have been in turn related to changes in metabolic rate, oxygen consumption, and blood flow in specific brain structures both in humans and experimental animals. However, direct evidence showing changes in neuronal firing in specific brain regions during fentanyl-induced epileptoid activity has not been reported. Eight adult male cats with chronically implanted bipolar electrodes in the mesencephalic reticular formation, hippocampus, amygdala, and parieto-occipital cortex were included in the study. Different treatments, i.e., vehicle-fentanyl or diazepam-fentanyl, were administered to the experimental animals at 7-day intervals under neuromuscular blockade and assisted ventilation. Electroencephalographic (EEG) seizures, grouped and isolated spikes, and significant increases of multineuronal activity (MUA) were elicited by fentanyl, 50 micrograms/kg iv, in these brain structures. Both EEG and MUA changes reached their maximal values within 6 min of fentanyl administration, and then diminished as time elapsed. Diazepam, 100, 200, or 400 micrograms/kg, but not 50 micrograms/kg iv, significantly reduced or prevented the fentanyl-induced epileptoid EEG activity and MUA increases. The present results show that both fentanyl-induced epileptoid EEG activity as well as the concomitant increase in MUA of brain subcortical structures are part of the same epileptogenic phenomenon, mainly generated at limbic structures. In addition, the effects of diazepam against both epileptoid EEG activity and increase of MUA of brain subcortical structures support the use of benzodiazepines as premedicants for fentanyl anesthesia in order to prevent or to reduce epileptoid phenomena that can result from opioid administration during the anesthetic procedures.

Animals↗
PubMed1997

Discriminative stimulus effects of opioids in pigeons trained to discriminate fentanyl, bremazocine and water: evidence of pharmacological selectivity.

The purpose of the present investigation was to examine the discriminative stimulus effects of opioids with activity at mu and kappa opioid receptors, in pigeons trained to discriminate the mu opioid fentanyl, the kappa opioid bremazocine and water in a three-choice discrimination task. The apparent pkB values obtained for naloxone as an antagonist of the stimulus effects of fentanyl were higher than those obtained against the bremazocine stimulus. The mu opioids morphine and l-methadone substituted for the fentanyl stimulus, the kappa opioids U50,488 and U69,593 substituted for the bremazocine stimulus, and the non-opioid pentobarbital failed to substitute for either the fentanyl or bremazocine stimulus. A series of opioids with activity at both the mu and kappa opioid receptor sites, including nalorphine, butorphanol, buprenorphine, nalbuphine, ethylketocyclazocine, (-)-ketocyclazocine, (-)-n-allylnormetazocine (NANM) and levallorphan, produced high levels of substitution for the fentanyl stimulus without producing appreciable levels of substitution for the bremazocine stimulus. At doses that did not substitute for the fentanyl stimulus, (-)-NANM, levallorphan, nalorphine and nalbuphine partially antagonized the bremazocine stimulus (i.e. produced responding on the water key). Butorphanol and buprenorphine also antagonized the bremazocine stimulus, although this effect was evidenced only at doses that substituted for the fentanyl stimulus. In contrast, even when tested up to doses that markedly decreased rates of responding, ethylketocyclazocine and (-)-ketocyclazocine failed to antagonize the bremazocine stimulus. The present findings indicate that in this three-choice task the fentanyl-like substitution patterns produced by opioids with activity at both the mu and kappa opioid receptors are similar to those reported in pigeons trained to discriminate either fentanyl or bremazocine from saline (i.e. two-choice tasks). In this task, however, the level of kappa antagonist activity evidenced by these opioids was considerably less than that obtained in pigeons trained to discriminate bremazocine from saline.

Analgesics↗
PubMed1998

Anaesthesia for caesarean delivery: low-dose epidural bupivacaine plus fentanyl.

To determine the acceptability of epidural bupivacaine-induced sixth thoracic (T6) sensory blockade and the analgesic efficacy of epidural fentanyl 50 microg, 24 parturients undergoing elective caesarean section were given a test dose of lidocaine 60 mg plus epinephrine followed by 10 ml of either 0.5 % bupivacaine (control group) or 0.5 % bupivacaine plus 50 microg fentanyl (fentanyl group) in a randomized double-blind manner. Fifteen minutes later loss of pinprick sensation was determined. Additional local anaesthetic was titrated to achieve T6 sensory blockade. Intraoperative pain intensity was assessed using a 10 cm visual analogue scale (VAS); total dose of bupivacaine and need for i.v. rescue fentanyl were recorded. The incidence of intraoperative respiratory depression, nausea, vomiting and pruritus were documented. Mean (+/- SD) volume of bupivacaine was 14.1 +/- 3.05 ml versus 13 +/- 1.48 ml for the control and fentanyl groups respectively. The most severe intraoperative VAS for pain was significantly (P=0.023) lower in the fentanyl group (0.4 +/- 0.08 cm) than in the control group (3.1 +/- 0.3 cm). Rescue fentanyl was administered in 40% and 0% of patients in the control and fentanyl groups respectively. The incidence of side-effects was unaffected by treatment group. Apgar scores were similar in the two groups. We conclude that following administration of 10-15 ml 0.5% bupivacaine plus fentanyl 50 microg, T6 sensory blockade is associated with good intraoperative analgesia without obvious maternal or neonatal respiratory depression.

Clinical Trial↗
PubMed2004

Risk of constipation in patients prescribed fentanyl transdermal system or oxycodone hydrochloride controlled-release in a California Medicaid population.

OBJECTIVE: To compare the risk of developing constipation between patients prescribed fentanyl transdermal system or oxycodone hydrochloride (HCl) controlled-release. DESIGN: California Medicaid (Medi-Cal) claims data. SETTING: Medicaid beneficiaries in California. PARTICIPANTS: Chronic pain patients who received a prescription for transdermal fentanyl or oxycodone controlled-release between October 1, 1997, and February 28, 2000, for at least three consecutive months. MAIN OUTCOME MEASURES: Constipation was defined using the International Classification of Diseases, Ninth Revision, Clinical Modification code (ICD-9-CM 564.0). The association between long-acting opioid use and constipation was determined by multivariate logistic regression after controlling for drug strength, short-acting opioid usage, and comorbidities. Odds ratios (ORs), 95% confidence intervals (CIs), and P values were reported. RESULTS: A total of 2,095 patients were included in the regression analysis (transdermal fentanyl = 877; oxycodone controlled-release = 1,218). Seventy-five patients received a constipation diagnosis (transdermal fentanyl = 28; oxycodone controlled-release = 47). Approximately 40% of patients were at least 65 years of age. Overall, oxycodone controlled-release patients had a significantly greater risk of developing constipation compared with transdermal fentanyl patients (transdermal fentanyl: n = 877; oxycodone controlled-release: n=1,218; OR = 2.55; 95% CI = 1.33-4.89; P = 0.005). Among patients who were 65 years or older, oxycodone controlled-release patients were 7.33 times more likely to be constipated than transdermal fentanyl patients (transdermal fentanyl: n = 518; oxycodone controlled-release: n = 317; OR = 7.33; 95% CI = 1.98-27.13; P = 0.003). CONCLUSION: These findings suggest that patients prescribed transdermal fentanyl may have a significantly lower risk of developing constipation compared with oxycodone controlled-release, particularly in the elderly.

Journal Article↗
PubMed2004

Patient-controlled transdermal fentanyl hydrochloride vs intravenous morphine pump for postoperative pain: a randomized controlled trial.

CONTEXT: Patient-controlled analgesia (PCA) with morphine is commonly used to provide acute postoperative pain control after major surgery. The fentanyl hydrochloride patient-controlled transdermal system eliminates the need for venous access and complicated programming of pumps. OBJECTIVE: To assess the efficacy and safety of an investigational patient-controlled iontophoretic transdermal system using fentanyl hydrochloride compared with a standard intravenous morphine patient-controlled pump. DESIGN, SETTING, AND PATIENTS: Prospective randomized controlled parallel-group trial conducted between September 2000 and March 2001 at 33 North American hospitals, enrolling 636 adult patients who had just undergone major surgery. INTERVENTIONS: In surgical recovery rooms, patients were randomly assigned to intravenous morphine (1-mg bolus every 5 minutes; maximum of 10 mg/h) by a patient-controlled analgesia pump (n = 320) or iontophoretic fentanyl hydrochloride (40- microg infusion over 10 minutes) by a patient-controlled transdermal system (n = 316). Supplemental analgesia (morphine or fentanyl intravenous boluses) was administered as needed before and for the first 3 hours after activation of the PCA treatments. Patients then used the PCA treatments without additional analgesics for up to 72 hours. MAIN OUTCOME MEASURES: The primary efficacy variable was patient global assessment of the method of pain control during the first 24 hours. Additional efficacy measures were the proportion of patients discontinuing the study because of inadequate analgesia for any reason, patient-reported pain intensity scores on a 100-mm visual analog scale (VAS), and patient global assessments at 48 and 72 hours. Adverse effects were also recorded. RESULTS: Ratings of good or excellent after 24 hours of treatment for the method of pain control were given by 73.7% of patients (233/316) who used transdermal fentanyl PCA and 76.9% of patients (246/320) who used intravenous morphine PCA; treatment difference was -3.2% (95% confidence interval, -9.9% to 3.5%; P =.36). Early patient discontinuations (25.9% fentanyl vs 25.0% morphine; P =.78) and last pain intensity scores (32.7 fentanyl vs 31.1 morphine on the VAS; P =.45) were not different between the 2 treatments. With continued treatment for up to 48 or 72 hours, more than 80% of patient assessments in each treatment group were good or excellent. The incidence of opioid-related adverse events was similar between the groups. CONCLUSION: An investigational PCA transdermal system using iontophoresis to deliver fentanyl provided postsurgical pain control equivalent to that of a standard intravenous morphine regimen delivered by a PCA pump.

Administration, Cutaneous↗
PubMed1986

Opioid activity and distribution of fentanyl metabolites.

Fentanyl, a short-term analgesic frequently used in neuroleptanalgesia, has in a number of cases been reported to cause unexpected, severe postanesthetic respiratory depression which can successfully be treated with naloxone. Several explanations for this rebound effect produced by fentanyl (in combination with other drugs) have been proposed, though so far none has proved completely satisfactory. The possibility that this effect may be due to a secondary accumulation of fentanyl or fentanyl metabolites with opioid activity in the brain has led us to investigate the relative opioid potency of several known or proposed metabolites by measuring their inhibitory action on the contraction of guinea-pig ileum in comparison with that of morphine, pethidine, and fentanyl itself. Two proposed metabolites containing the phenethyl sidechain were found to possess an opioid activity lying between that of morphine and pethidine, whereas metabolites without the side-chain were generally less active than pethidine. Using thin-layer chromatography, it was possible to detect one of these proposed active metabolites in vivo in rats. This result may have some relevance for the understanding of the fentanyl rebound. However, the possibility that multiple doses of fentanyl, such as may be given during neuroleptanalgesia, or interactions with other drugs, e.g. tranquilizers and general anesthetics, may be the cause of fentanyl rebound, remains open.

Animals↗
PubMed1994

Transdermal fentanyl in uncontrolled cancer pain: titration on a day-to-day basis as a procedure for safe and effective dose finding--a pilot study in 20 patients.

All communications on the use of transdermal fentanyl as well as the recommendations of the manufacturer include the direction that patients should be titrated with a short-acting narcotic to control their cancer pain before they are converted to a fentanyl transdermal therapeutic system (TTS). We investigated the possibility of avoiding this titration phase by immediate fentanyl TTS therapy in patients with uncontrolled cancer pain. Dose finding was performed by direct titration of fentanyl TTS according to clinical necessity on a day-to-day basis. Morphine solution for rescue medication was available. Short-term follow-up was 28 days, and 20 patients (10 in- and 10 outpatients) were evaluable. On the average, sufficient pain control [visual analogue scale (VAS) < 35 mm] was reached within 48 h of the start of fentanyl TTS. The mean VAS values before and during fentanyl TTS therapy were 53 mm (before), 27 mm (week 1), 21 mm (week 2), 18 mm (week 3) and 21 mm (week 4). There were statistically significant lower VAS values at all follow-up times compared to pretreatment values (e.g. pretreatment to day 1: P = 0.019; pretreatment to day 28: P = 0.002; Wilcoxon sign-rank test). The mean fentanyl TTS doses were 70 micrograms/h (week 1), 98 micrograms/h (week 2), 107 micrograms/h (week 3) and 116 micrograms/h (week 4). The differences of mean fentanyl TTS does were significantly different between days 1 and 7 (P < 0.001) and between days 8 and 14 (P = 0.006), but not between days 15 and 21 and days 22 and 28.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Cutaneous↗