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PubMed1993

Effects of fentanyl on coronary blood flow distribution and myocardial oxygen consumption in the dog.

Little data exist on the effects of fentanyl on coronary blood flow (CBF), myocardial oxygen balance, and the regional distribution of blood flow. These studies were designed to determine whether fentanyl had any intrinsic effects on myocardial oxygen consumption (MVO2) and blood flow distribution. In anesthetized dogs, fentanyl was administered in a dose of 50 micrograms/kg and various measurements were made at 5 and 20 minutes. After hemodynamic recovery from the fentanyl, the animals were treated with atropine to block the known vagomimetic effect of fentanyl and challenged with acetylcholine (3.5 micrograms/kg); then fentanyl (50 micrograms/kg) was again administered and measurements made at 5 and 20 minutes. In the untreated dogs at 5 minutes post-fentanyl, heart rate (HR) decreased 30% and at 20 minutes decreased 29%. Treatment with atropine essentially eliminated HR changes at both time periods. Mean arterial pressure (MAP) fell by 20% and 22% at 5 minutes and 20 minutes, respectively, in the untreated group, but when atropine was administered, MAP was observed to be intermediate between baseline and the untreated animals. Left ventricular MVO2 at 5 minutes in the untreated group was modestly but not significantly reduced. However, at 20 minutes post-fentanyl, MVO2 decreased significantly. MVO2 was essentially unchanged after atropine. Regional CBF (measured by radiolabelled microspheres) was unchanged at 5 minutes, but all layers exhibited significant reductions at 20 minutes. In the atropine group, only the LV epicardial area appeared to show decreases in flow.(ABSTRACT TRUNCATED AT 250 WORDS)

Anesthesia, Inhalation↗
PubMed2004

Cardiovascular and endocrine responses to cutaneous electrical stimulation after fentanyl in the ovine fetus.

OBJECTIVE: The purpose of this study was to determine whether physical stimulation is stressful to the ovine fetus, as judged from physiologic changes that are similar to those reported for other stressors (such as hypoxia); whether any stress response could be blocked by clinically used doses of fentanyl; and whether fentanyl alone had any potentially deleterious physiologic effects in the fetus. STUDY DESIGN: We investigated the effect of fentanyl analgesia on the cardiovascular and endocrine response to cutaneous electrical stimulation in the late gestation (>125 days) ovine fetus (n=7 fetuses). Chronically implanted catheters and blood flow probes were used to measure fetal arterial blood pressure, heart rate, carotid and femoral blood flow, pH, Po(2), Pco(2), lactate, cortisol, and beta-endorphin levels before, during, and for 1 hour after 5 minutes of cutaneous electrical stimulation to the lip, forelimb, and abdomen, in a crossover design. Clinically used 30 or 150 microg doses of fentanyl (which approximated 10 or 50 microg/kg estimated fetal weight) or saline solution were given intravenously to the fetus 2 minutes before stimulation. RESULTS: When compared with the control, stimulation caused a significant rise in fetal heart rate (P=.003; mean maximal rise, 48.6+/-14.0 beats/min, 0-10 minutes after the start of stimulation) but caused no change in any other parameters studied. Neither dose of fentanyl attenuated the changes in heart rate that were observed in response to stimulation alone. Fentanyl alone significantly increased fetal heart rate, carotid blood flow, and lactate and cortisol levels and significantly decreased pH and Po(2). CONCLUSION: Cutaneous electrical stimulation in the fetal sheep causes an increase in heart rate, which fentanyl does not block. Fentanyl itself has significant effects on the cardiovascular and endocrine system, which might adversely affect the fetus.

Analgesics, Opioid↗
PubMed2005

Equipotent doses of transdermal fentanyl and transdermal buprenorphine in patients with cancer and noncancer pain: results of a retrospective cohort study.

BACKGROUND: The equipotency ratio of transdermal (TD) fentanyl to oral morphine has been established as 1:100; for buprenorphine TD, a ratio of 1:75 has been proposed, although this ratio has not been confirmed in clinical studies. Growing evidence from clinical practice, in which much lower doses of buprenorphine are used, suggests that this conversion ratio may be too high. OBJECTIVE: The aim of this study was to compare calculated equipotent oral morphine doses of fentanyl TD with equipotent oral morphine doses of buprenorphine TD prescribed in clinical practice. METHODS: This retrospective study identified patients with cancer and noncancer pain who had received > or =1 prescription for fentanyl TD or buprenorphine TD (the all-patients groups) from the German IMS Disease Analyzer-mediplus database, which contains all relevant data concerning drug prescriptions from 400 practices in Germany. Also identified were subgroups of the all-patients groups who had received long-term treatment with fentanyl TD or buprenorphine TD and were considered to have similar pain intensity, as they had previously received similar analgesic medication (the identical-cohort groups). Mean prescribed daily doses for the all-patients and identical-cohort groups were calculated based on the distribution of prescribed patch strengths. Because patients could have applied >1 patch, mean prescribed daily doses were also calculated based on an assumption of double application when appropriate. Equipotent oral morphine doses were estimated using equipotency ratios of 1:100 for fentanyl TD and 1:75 for buprenorphine TD. RESULTS: The all-patients groups consisted of 2198 patients with noncancer pain and 2544 patients with cancer pain; the identical-cohort groups consisted of 380 patients with noncancer pain and 496 patients with cancer pain (529 women, 347 men; mean age, 74 years [range, 25-101 years]). Equipotent doses of oral morphine were significantly lower in patients receiving buprenorphine TD compared with those receiving fentanyl TD (P < 0.001). In cancer patients, the equipotent oral morphine doses of fentanyl TD and buprenorphine TD were 130.9 to 138.9 mg and 85.2 to 88.8 mg, respectively; in noncancer patients, the corresponding values were 117.0 to 118.3 mg and 80.2 to 80.9 mg. Based on these results, an equipotency ratio of 1:110 to 1:115 for buprenorphine TD would appear to be more appropriate than the proposed ratio of 1:75. CONCLUSIONS: The fact that this retrospective analysis conducted in identical cohorts showed lower calculated equipotent oral morphine doses in the buprenorphine TD groups compared with the fentanyl TD groups calls into question the proposed 1:75 ratio for conversion of buprenorphine TD to equipotent oral morphine doses. Based on the findings of the present study, an equipotency ratio of 1:110 to 1:115 may be more appropriate. However, confirmative data from prospective randomized clinical trials are needed.

Administration, Cutaneous↗
PubMed1999

Opioid neurotoxicity: fentanyl-induced exacerbation of cerebral ischemia in rats.

We tested the hypothesis that fentanyl would worsen ischemia-induced brain damage. In two sequential protocols forty rats were physiologically monitored and controlled. In protocol 1, rats were randomized (n=10/group) to 30 min of control (N2O plus 0.4% halothane), low dose fentanyl (loading dose [LD] 50 micrograms kg-1, maintenance dose [MD] 2 micrograms kg-1 min-1), or high-dose fentanyl (LD 800 micrograms kg-1, MD 32 micrograms kg-1 min-1). After 15 min of fentanyl or sham infusion trimethaphan 0.5 mg was given i.v. and 3 min later bilateral carotid artery occlusion and blood withdrawal-induced hypotension were maintained for 12 min. At 18 h postischemia rats underwent cerebral perfusion fixation. Brain areas were graded from 0 (normal) to 5. In addition to analysis of specific regions, neuropathologic scores were also summated over all brain regions and analyzed to compute a summed neuropathologic score. In protocol 2, five control and five high-dose fentanyl rats were treated identically except that post-ischemic oxygenation was maintained for 6 h and cerebral perfusion-fixation was performed 6 h post-ischemia. Only the caudate/putamen was examined in protocol 2. Fentanyl worsened lesions in both fentanyl groups' summed neuropathologic scores (P=0.002) in protocol 1 and specifically, in the caudate/putamen (P<0.01) in both protocols. Fentanyl in both high and low doses can exacerbate incomplete forebrain ischemia in rats.

Analgesics, Opioid↗
PubMed2002

Possible involvement of mu1-opioid receptors in the fentanyl- or morphine-induced antinociception at supraspinal and spinal sites.

Fentanyl has been shown to be a potent analgesic with a lower propensity to produce tolerance and physical dependence in the clinical setting. The present study was designed to investigate the mechanisms of fentanyl- or morphine-induced antinociception at both supraspinal and spinal sites. In the mouse tail-flick test, the antinociceptive effects induced by both fentanyl and morphine were blocked by either the mu1-opioid receptor antagonist naloxonazine or the mu1/mu2-opioid receptor antagonist beta-funaltrexamine (beta-FNA) after s.c., i.c.v. or i.t. injection. In contrast, both fentanyl and morphine given i.c.v. or i.t. failed to produce antinociception in mu1-deficient CXBK mice. These findings indicate that like morphine, the antinociception induced by fentanyl may be mediated predominantly through mu1-opioid receptors at both supraspinal and spinal sites in mice. We also determined the ED50 values for s.c.-, i.c.v.- and i.t.-administered fentanyl- or morphine-induced antinociception in mice. The ED50 values for s.c.-, i.c.v.- and i.t.-administered fentanyl-induced antinociception were 73.7, 18.5 and 1.2-fold lower than that of morphine, respectively. The present data clearly suggest the usefulness of peripheral treatment with fentanyl for the control of pain.

Analgesics, Opioid↗
PubMed1999

Effects of fentanyl on cellular immune functions in man.

In order to analyze the effects of the opioid agonist fentanyl on cells of the innate immune system, seven healthy individuals were treated intravenously with the opioid fentanyl and five subjects received a placebo. Respiratory burst of polymorphonuclear cells (PMNC) and phenotypes of peripheral blood lymphocytes (PBL) were analyzed from blood samples drawn before, 15 and 30 min after fentanyl or placebo application. In addition, in vitro effects of fentanyl on natural killer (NK) activity was assessed. Fentanyl administration affected neither superoxide production of PMNC nor circulating numbers of B-and T-lymphocytes. In contrast, NK cell (CD16+/CD56+) numbers significantly increased in response to fentanyl. However, no direct influence of fentanyl on NK cell function in vitro could be detected. These results suggest a transient effect of fentanyl on NK cell circulation which seemed to be centrally mediated rather than a direct effect of this opioid on NK cells.

Adult↗
PubMed2002

Patient-controlled analgesia and sedation with fentanyl in phacoemulsification under topical anesthesia.

PURPOSE: To investigate the effects of intravenous (IV) patient-controlled sedation/analgesia with fentanyl during phacoemulsification surgery under topical anesthesia. SETTING: Adnan Menderes University Medical School, Departments of Ophthalmology and Anesthesiology and Reanimation, Aydin, Turkey. METHODS: In this double-blind randomized study, 68 patients were randomly allocated to 2 groups. In the fentanyl group comprising 34 patients, fentanyl was administered by patient-controlled analgesia (PCA) equipment in 5 microg bolus doses with a lockout period of 5 minutes after an IV loading dose of 0.7 microg/kg in 2 mL balanced salt solution. In the control group comprising 34 patients, a balanced salt solution was given without an analgesic drug by PCA equipment. Verbal pain scale (VPS) and sedation scores were recorded preoperatively and 5, 10, 15, 20, and 30 minutes after the start of surgery. Patient comfort and surgeon satisfaction were assessed postoperatively. RESULTS: The sedation score was higher in the fentanyl group than in the control group at 5 and 10 minutes (P =.006 and P =.012, respectively). The VPS scores were higher in the control group than in the fentanyl group at 15 and 20 minutes (P =.02 and P =.016, respectively). Patients pressed the button for additional analgesia 2.6 times +/- 3.9 (SD) in the control group and 0.9 +/- 1.6 times in the fentanyl group (P =.025). Patient and surgeon satisfaction were higher in the fentanyl group than the control group (P =.023 and P =.018, respectively). CONCLUSIONS: The results of this study suggest that IV PCA with fentanyl has supplemental effects on analgesia and sedation during cataract surgery under topical anesthesia and increases patient comfort and surgeon satisfaction.

Adult↗
PubMed1998

Combined intrathecal fentanyl and neostigmine: therapy for postoperative abdominal hysterectomy pain relief.

STUDY OBJECTIVE: To evaluate the analgesic action of spinal neostigmine as part of a multimodal analgesic therapy approach including spinal neostigmine and spinal fentanyl for postoperative pain relief DESIGN: Randomized, prospective study. SETTING: Teaching hospital. PATIENTS: 50 ASA physical status I and II patients undergoing abdominal hysterectomy. INTERVENTIONS: Patients were assigned to one of five groups (n = 10) to receive 15 mg bupivacaine plus 1 ml of the test drug intrathecally. The control group (CG) received saline as the test drug, the fentanyl group (FG) received 25 microg fentanyl; the neostigmine group (NG) received 25 microg neostigmine; the fentanyl-neostigmine 10 microg group (FNG10) was given 10 microg fentanyl plus 10 microg neostigmine; and the fentanyl-neostigmine 25 microg group (FNG25) received 25 microg fentanyl plus 25 microg neostigmine. Pain and nausea were evaluated using a 10-cm visual analog scale (VAS). MAIN RESULTS: The analgesic consumption, in 24 hours was greatest in CG, next highest in NG, FG, and FNG10 where consumption was the same in the three groups; and least in FNG25 (p < 0.05). The time to first rescue analgesic medication was greatest for FNG25 compared with the other groups (>5 hours compared with 2 to 3 hours; p < 0.05). VAS showed no statistically significant differences for pain impression, intraoperative and postoperative nausea, or occurrence of vomiting (p > 0.05). CONCLUSION: The combination of 25 microg neostigmine with 25 microg fentanyl given intrathecally with 15 mg of hyperbaric bupivacaine delayed postoperative pain and lowered the number of rescue analgesics. Because the better quality of analgesia was obtained with an increased (although not statistically significant difference) incidence of untoward side effects, larger samples should be studied before its routine use is recommended.

Adult↗
PubMed2004

Efficacy and side effect profile of varying doses of intrathecal fentanyl added to bupivacaine for labor analgesia.

The purpose of this randomized, double blinded and controlled study was to determine the optimal dose of intrathecal fentanyl when combined with bupivacaine 2.5 mg for initiation of labor analgesia. Parous parturients with cervical dilation between 3 and 5 cm were randomized to receive intrathecal fentanyl 0 (control), 5, 10, 15, 20 or 25 micrograms, combined with bupivacaine 2.5 mg, followed by a lidocaine/epinephrine epidural test dose. Visual analog pain scores (VAPS) and the presence of side effects were determined every 15 min until the parturient requested additional analgesia. Fetal heart rate (FHR) tracings were compared between groups. All parturients who received fentanyl >/= 15 micrograms had VAPS < 20 mm and duration of analgesia > 15 min, but this was not true for all parturients with fentanyl doses < 15 micrograms. Duration of analgesia was shorter for fentanyl groups 0, 5 and 10 micrograms, compared to groups 15, 20 and 25 micrograms, but there was no difference between the 15, 20 and 25 micrograms groups. There was no difference in the incidence of nausea and vomiting, or in FHR tracing changes. The incidence of pruritus was greater in all fentanyl groups compared to control. These data suggest that, when combined with intrathecal bupivacaine 2.5 mg, fentanyl 15 micrograms provides satisfactory analgesia to all parturients. Higher fentanyl doses produced no additional benefit in duration or quality of analgesia.

Adult↗
PubMed2006

The effect of nitric oxide on fentanyl and haloperidol-induced catalepsy in mice.

BACKGROUND AND OBJECTIVES: This study was designed to investigate the role of nitric oxide on catalepsy induced by fentanyl and haloperidol. METHODS: Male albino mice were treated either with fentanyl (0.1-0.2 mg kg-1, s.c.) or haloperidol (0.5-2 mg kg-1, i.p.). The non-selective nitric oxide synthase inhibitor, NG-nitro-L-arginine (10 mg kg-1, i.p.), selective neuronal nitric oxide synthase inhibitor, 7-nitroindazole (3 mg kg-1, i.p.), and nitric oxide donors, L-arginine (30-300 mg kg-1, i.p.) and D-arginine (30 mg kg-1, i.p.), were applied 20 min prior to fentanyl or haloperidol injection. A mu-opioid receptor antagonist naloxone (1 mg kg-1, i.p.) was also given in some groups. The cataleptic status of mice was assessed by placing animals in a rearing position in the cage. If the mouse maintained cataleptic posture for more than 20 s, it was scored as cataleptic and duration of catalepsy was expressed in terms of minutes. RESULTS: Both NG-nitro-L-arginine and 7-nitroindazole prolonged fentanyl-induced catalepsy (fentanyl: 3.6+/-0.8 min; fentanyl+NG-nitro-L-arginine: 77.4+/-14.6 min, fentanyl+7-nitroindazole: 56.0+/-10.4 min; n=6; P<0.01). This effect was reversed by L-arginine and naloxone, but not by D-arginine. Nitric oxide synthase inhibitors also prolonged the cataleptic action of haloperidol but to a lesser extent (haloperidol: 72.0+/-6.3 min; haloperidol+NG-nitro-L-arginine: 98.5+/-6.3 min, haloperidol+7-nitroindazole: 89.6+/-2.2 min; n=6; P<0.05). The prolongation of haloperidol-induced catalepsy with nitric oxide synthase inhibitors was not reversed by L-arginine. CONCLUSION: These results suggest a common mechanism between mu-opioid receptors and the nitric oxide system in the development of fentanyl-induced catalepsy in mice different from haloperidol-induced catalepsy.

Animals↗
PubMed2003

Fentanyl decreases propofol requirement for laryngeal mask airway insertion.

BACKGROUND: Since fentanyl is a potent depressant of the upper airway reflex, preadministration of fentanyl may facilitate insertion of the laryngeal mask airway (LMA) using propofol. Accordingly, we tested the hypothesis that fentanyl pretreatment would reduce the dose of propofol required for the LMA insertion. METHODS: Forty-one healthy patients without sedative premedication were randomly assigned to either fentanyl group, receiving fentanyl 2 microg kg-1 intravenously, or control group, receiving equal volumes of normal saline. Then, 3 ml of 2% lidocaine was given intravenously to alleviate pain associated with propofol administration. Thirty s after the fentanyl or saline injection, a predetermined dose of 1% propofol was given at a rate of 100 mg min-1. Insertion of the LMA was attempted 90 s after the completion of the propofol injection. The dose of propofol given to a particular patient was determined by the response of the preceding patient in that group to a higher or lower dose, using the up-and-down method. The first patient in each group received 2.5 mg kg-1 of propofol, while the step-size was 0.25 mg kg-1. Patients responses were assessed by a blinded observer. RESULTS: ED50 and ED95 of propofol requirements were significantly less in the fentanyl group (0.82, 1.17 mg kg-1, respectively) than those in the control group (2.39, 2.62 mg kg-1, P < 0.001). CONCLUSION: Our results indicate that preadministration of fentanyl 2 microg kg-1 decreases the propofol requirement for the LMA insertion.

Adolescent↗
PubMed2001

Pre-emptive efficacy of epidural fentanyl in elective abdominal surgery.

BACKGROUND AND AIM: This study determines whether epidural fentanyl given before incision decreases the requirements for opioid analgesia postoperatively, compared with the same dose of epidural fentanyl given after the surgery. METHODS: Forty patients scheduled to undergo elective abdominal surgery were randomly allocated between two groups according to the time of administered of fentanyl. None of the patients in either group received premedication. Prior to induction of general anaesthesia an epidural catheter was inserted at the L2-3 interspace and flushed with 0.9% NaCl. Patients then received 100 micrograms fentanyl in 10 mL 0.9% NaCl through this catheter either 15 min before awaking at the end of the operation (group I), or else the same dose given at an estimated time of 15 min before the start of surgery (group II). Postoperative analgesia consisted of patient-controlled intravenous fentanyl. The amount of fentanyl used by the patients was noted at 2, 4, 8, 12 and 24 h after surgery. Pain scores and sedation scores were assessed at 0, 2, 4, 8, 12 and 24 h postoperatively. RESULTS: The consumption of fentanyl was similar in both groups in all studied periods postoperatively. The mean pain score was lower for patients in group I than group II immediately after operation. There were no statistically significant differences between the mean pain scores of groups at 2, 4, 8, 12 and 24 h after operation. Mean sedation scores were similar in both groups at all times postoperatively. CONCLUSION: This study showed that the dose of fentanyl administered epidurally prior to surgical incision did not produce any clinically useful pre-emptive analgesic effect.

Abdomen↗
PubMed2001

Remifentanil and fentanyl during anaesthesia for major abdominal and gynaecological surgery. An open, comparative study of safety and efficacy.

BACKGROUND: and objective This open, multicentre study compared the efficacy and safety of remifentanil with fentanyl during balanced anaesthesia with 0.8% isoflurane (end-tidal concentration) for major abdominal and gynaecological surgery, and the efficacy and safety of remifentanil for pain management in the immediate postoperative period. METHODS: Two-hundred and eighty-six patients were randomized to receive remifentanil 1 microg kg(-1) followed by 0.2 microg kg(-1) min-1 (n=98), remifentanil 2 microg kg(-1) followed by 0.4 microg kg(-1) min(-1) (n=91) or fentanyl 3 microg kg(-1) (n=97) at induction. Thereafter, the study opioids and isoflurane were titrated to effect during the operation. RESULTS: Compared with fentanyl, remifentanil 2 microg kg(-1) followed by 0.4 microg kg(-1) min(-1) reduced the incidence of response to tracheal intubation (30% vs. 13%, P < 0.01), skin incision (33% vs. 4%, P < 0.001) and skin closure (11% vs. 3%, P < 0.05), respectively. Patients receiving remifentanil 1 microg kg(-1) followed by 0.2 microg kg(-1) min(-1) had fewer responses to skin incision than the fentanyl group (12% vs. 33%, P < 0.001), but the incidences of response to tracheal intubation and skin closure were similar. Significantly fewer patients in both remifentanil groups had > or = 1 responses to surgical stress intraoperatively compared with fentanyl (68% and 48% vs. 87%, P < 0.003). The mean isoflurane concentrations required were less in both remifentanil groups compared with the fentanyl group (0.1%, P=0.05). In remifentanil-treated patients, continuation of the infusion at 0.1 microg kg(-1) min(-1) with titration increments of +/- 0.025 microg kg(-1) min(-1) was effective for the management of immediate postoperative pain prior to transfer to morphine analgesia. However, a high proportion of patients experienced at least moderate pain whilst the titration took place. CONCLUSIONS: Anaesthesia combining isoflurane with a continuous infusion of remifentanil was significantly more effective than fentanyl at blunting responses to surgical stimuli. Significantly fewer patients responded to tracheal intubation with remifentanil at 0.4 microg kg(-1) min(-1), supporting the use of a higher initial infusion rate before intubation. Both remifentanil and fentanyl were well-tolerated, with reported adverse events typical of mu-opioid agonists.

Abdomen↗
PubMed2000

A comparison of fentanyl and sufentanil in patients undergoing coronary artery bypass graft surgery.

OBJECTIVE: To compare fentanyl and sufentanil, administered in equipotent concentrations by target-controlled infusion, as components of a balanced anesthetic in patients undergoing coronary artery bypass graft (CABG) surgery. DESIGN: A prospective, randomized, double-blind trial. SETTING: A university hospital. PARTICIPANTS: Twenty-one patients undergoing nonemergent, primary CABG surgery. INTERVENTIONS: Patients received fentanyl (group F, n = 10) or sufentanil (group S, n = 11) by target-controlled infusion throughout the pre-cardiopulmonary bypass (CPB) period. To ensure equipotency, the target effect-site concentrations employed (fentanyl, 8.1 ng/mL, and sufentanil, 0.68 ng/mL) were equal to the IC50 for electroencephalographic effect. Isoflurane was administered as needed to maintain pre-CPB hemodynamics near preoperative baseline values. MEASUREMENTS AND MAIN RESULTS: Hemodynamics and end-tidal isoflurane concentration were measured every 15 to 30 seconds. Serum opioid concentrations were measured 5 times between induction and CPB. Opioid cost was based on the number of ampules opened to provide the administered dose. The 2 groups were similar demographically. The pre-CPB serum opioid concentrations were constant and averaged fentanyl, 5.8 +/- 1.9 ng/mL, and sufentanil, 0.59 +/- 0.13 ng/mL. Pre-CPB hemodynamics were stable and similar in both groups. Pre-CPB end-tidal isoflurane requirements did not differ between groups and averaged 0.46 +/- 0.21% in group F and 0.56 +/- 0.24% in group S. The duration of post-operative endotracheal intubation was 9.1 +/- 5.0 hours in group F and 8.0 +/- 3.2 hours in group S (p = NS). The cost per patient of fentanyl (Canadian $6.12 +/- 1.04) was less than that of sufentanil (Canadian $17.47 +/- 4.65). CONCLUSIONS: When administered in a constant 10:1 concentration ratio, fentanyl and sufentanil do not differ in their ability to facilitate pre-CPB hemodynamic control. Although both opioids were relatively inexpensive, the acquisition cost of fentanyl was less than sufentanil. A recommendation regarding the opioid of choice for routine use in patients undergoing CABG surgery awaits more rigorous studies of recovery and cost after equipotent doses of fentanyl and sufentanil. When combined with isoflurane, effect-site opioid concentrations near the IC50 for electroencephalographic effect provide excellent pre-CPB hemodynamic control in patients undergoing CABG surgery.

Adjuvants, Anesthesia↗
PubMed2000

Amino acids counteract the inhibitory effect of fentanyl on hepatocyte oxidative metabolism.

BACKGROUND/PURPOSE: Hypothermia is common after major surgery in newborns and can be triggered by intraoperative fentanyl analgesia. Recent studies have found that fentanyl inhibits hepatocyte mitochondrial oxidative metabolism, which is proportional to thermogenesis. In adults it has been shown that amino acids have a thermogenic effect, although the biochemical basis of this phenomenon is not known. The aim of this study was to test the hypothesis that amino acids counteract the inhibition of neonatal hepatocyte oxygen consumption by fentanyl. METHODS: Hepatocytes were isolated from suckling rats, and O2 consumption was measured polarographically. In experiment A hepatocytes were incubated with (1) palmitate alone (control), (2) palmitate plus fentanyl, (3) palmitate plus fentanyl plus amino acids, and (4) palmitate plus amino acids. In experiment B the effects of essential and nonessential amino acids were tested separately. In experiment C, to investigate whether the effect of amino acids is intramitochondrial, hepatocytes were incubated with amino acids plus inhibitors of mitochondrial respiration. RESULTS: In experiment A, fentanyl significantly inhibited O2 consumption (P = .006). This inhibition was reversed by amino acids (P < .001). In experiment B, both essential and nonessential amino acids reversed the effect of fentanyl (P < .001). In experiment C, there was no difference in O2 consumption in the presence of myxothiazol among the groups indicating that amino acids affect intramitochondrial O2 consumption. CONCLUSIONS: (1) Amino acids abolish the inhibitory effect of fentanyl on hepatocyte oxidative metabolism. (2) Amino acids affect intramitochondrial O2 consumption and therefore thermogenesis. (3) Perioperative administration of amino acids in neonates may help to prevent hypothermia and its deleterious effects.

Adjuvants, Anesthesia↗
PubMedDate not supplied

Intrathecal fentanyl-induced pruritus is more severe in combination with procaine than with lidocaine or bupivacaine.

BACKGROUND AND OBJECTIVES: Fentanyl is used as an additive to prolong intrathecal anesthesia with both lidocaine and low-dose bupivacaine in the outpatient setting to minimize voiding or discharge delays. Pruritus is the most common side effect. When using procaine as a substitute for lidocaine, we perceived an increased frequency and severity of pruritus. We compared prospectively the frequency and severity of itching with combinations of fentanyl with lidocaine, bupivacaine, and procaine. METHODS: After institutional review board approval, 135 patients requesting neuraxial anesthesia were asked to evaluate the presence and severity (using a 100 point verbal pruritus score [VPS]) of itching 30 minutes after injection of their spinal anesthetic, on arrival to the postanesthesia care unit (PACU), and at the time of resolution of their block. Choice of anesthetic drug and dose and the use of intravenous sedation was left to the discretion of the attending and resident anesthesiologist. RESULTS: Thirty-three patients received lidocaine and fentanyl, 47 received bupivacaine and fentanyl, and 55 received procaine and fentanyl. In the lidocaine group, 21% of patients experienced pruritus compared with 55% of the bupivacaine group and 55% of the procaine group (P =.003). The average VPS at 30 minutes postblock was 18.4 in the procaine group compared with 0 and 5.5 in the lidocaine and bupivacaine groups (P =.06). On admission to the PACU, it was 37 compared with 16 and 20 for lidocaine and bupivacaine, respectively (P =.006). CONCLUSION: Procaine produces a higher frequency of pruritus than that seen with lidocaine-fentanyl combinations and a greater severity of pruritus than seen with lidocaine-fentanyl and bupivacaine-fentanyl spinal anesthesia. Reg Anesth Pain Med 2001;26:252-256.

Adjuvants, Anesthesia↗
PubMedDate not supplied

Epidural fentanyl speeds the onset of sensory block during epidural lidocaine anesthesia.

BACKGROUND AND OBJECTIVES: Shortening the onset time of sensory block is a practical goal to improve the quality of epidural anesthesia. The addition of fentanyl to a local anesthetic solution is widely used during epidural anesthesia. This randomized double-blind study examined the onset time of sensory block during epidural lidocaine anesthesia with and without added fentanyl to the epidural solution. METHODS: Thirty-six young male patients undergoing knee arthroscopy were randomly allocated into 3 groups of 12 patients each: epidural fentanyl (EF, epidural administration of 17 mL of 2% lidocaine plus 100 microg fentanyl and followed by intravenous (IV) injection of 2 mL of normal saline); IV fentanyl (IF, epidural administration of 17 mL of 2% lidocaine plus 2 mL of normal saline and followed by IV injection of 100 microg of fentanyl); and control (C, epidural administration of 17 mL of 2% lidocaine plus 2 mL of normal saline and followed by IV injection of 2 mL of normal saline). The sensory block was assessed by pinprick method. The hemodynamic changes, postepidural shivering, and side effects of epidural fentanyl were also recorded. RESULTS: There was no difference in the distribution of age, weight, and height among the 3 groups. The onset time of sensory block up to T(10) dermatome was significantly more rapid in the EF group (8.3 +/- 3.7 minutes) than that of the IF group (13.1 +/- 4.2 minutes, P <.05) or C group (14.2 +/- 5.4 minutes, P <.05). The upper level of sensory block was also significantly higher in the EF group. Although the incidence of shivering was lower in the EF group, this did not reach statistical significance. Postepidural arterial blood pressures and heart rates were no different among the 3 groups. No nausea, vomiting, pruritus, respiratory depression, urinary retention, or hypotension were observed in any patients. CONCLUSION: Epidural injection of the mixture of 100 microg fentanyl and 2% lidocaine solution accelerated the onset of sensory block during epidural lidocaine anesthesia without increased side effects.

Adjuvants, Anesthesia↗
PubMed1992

[Clinical comparison of various infusion regimens within the scope of postoperative on demand analgesia with fentanyl].

80 patients (ASA I-III, mean age 40-50 years, mean weight 59-68 kg) recovering from major gynaecological surgery (170-200 min) under balanced anaesthesia were randomly assigned to four groups to self-administer intravenous fentanyl during the early postoperative period. PCA devices were ODAC and Prominject with fentanyl demand doses of 34.5 or 34 micrograms, respectively, and lockout times of 1 or 5 min. Concurrent fentanyl infusion was none (group Prom), fixed-rate with 4 micrograms/h (group ODACf), tail-dose, i.e., a fixed-rate infusion with 17 mg/h for a maximum of 60 minutes following a valid demand (group Prom(t)), or adaptive, starting with 4 micrograms/h and being adapted to individual needs depending on total fentanyl consumption in the latest 60-minute period (group ODACa). Data were collected for fentanyl consumption, venous fentanyl serum concentrations in fixed intervals, actual and retrospective verbal rating pain scores (0-5), haemodynamic variables, respiratory rate, side effects and patients' acceptance. Mean duration of patient-controlled analgesia (PCA) was 15-17 hrs. During this period, an average of 12-18 demands were administered per patient, resulting in an average fentanyl consumption of 36-52 micrograms/h (0.57-0.94 micrograms/kg/h). Analgesic efficacy was good in all groups, mean pain scores ranging from 0.4 to 1.1 (actual) and 1.7 to 2.2 (retrospective). Mean duration of a single fentanyl bolus dose was highly variable, ranging from 58 to 90 min if calculated for the total observation period. Statistically significant differences were found for none of the above mentioned PCA parameters. As a trend, the adaptive-rate infusion strategy was favoured (lowest demand rate, best retrospective pain scores).(ABSTRACT TRUNCATED AT 250 WORDS)

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