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1.
Case history and presentationTwo non-human primates (Macaca fascicularis), weight 3.5 kg, enrolled in an experimental protocol received a 25 μg hour?1 transdermal fentanyl patch for postoperative analgesia. The following day both animals were clinically normal, but after a new induction of anaesthesia with ketamine, they developed severe and prolonged respiratory distress, profound coma and myosis.Management and follow-upAttempted reversal with naloxone was ineffective. After several hours of ventilation, both primates eventually died, 7 and 15 hours after ketamine injection, respectively. In both cases, the patch was discovered in the animal's cheek pouch. Subsequent fentanyl serum concentration measurements (8.29 and 14.80 μg L?1) confirmed fentanyl overdose.ConclusionsThis report of two fatal intoxications in non-human primates secondary to ingestion of a transdermal fentanyl patch demonstrates that this method of analgesia is inappropriate for non-human primates, because of their tendency to chew almost anything they can reach.  相似文献   

2.
Objective To measure the plasma fentanyl concentrations achieved over time with transdermal fentanyl patches in awake cats and cats undergoing anesthesia and ovariohysterectomy. Study design Randomized prospective experimental study. Animals Twenty‐four purpose‐bred cats. Methods Cats were randomly assigned to three groups for Part I of a larger concurrent study. Group P received only a 25 μg hour?1 transdermal fentanyl patch. Group P/A received the patch and anesthesia. Group A received only anesthesia. After a minimum 1‐week washout period, the cats were randomly reassigned to two groups for Part II of the larger study. Group P/A/O received the patch, anesthesia and ovariohysterectomy. Group A/O received anesthesia and ovariohysterectomy. Patches were left in place for 72 hours and plasma samples were obtained for fentanyl analysis while the patches were in place, and for 8 hours after patch removal for cats in Group P, P/A, and P/A/O. Results The 25 μg hour?1 transdermal fentanyl patches were well tolerated by the cats in this study (mean body weight of 3.0 kg) and no overt adverse effects were noted. Mean plasma fentanyl concentrations over time, mean plasma fentanyl concentrations at specific times (8, 25, 49, and 73 hours after patch placement), time to first detectable plasma fentanyl concentration, time to reach maximum plasma fentanyl concentration, maximum plasma fentanyl concentration, mean plasma fentanyl concentration from 8 to 73 hours, elimination half‐life, and total area under concentration (AUC) were not statistically different among the groups. Conclusions Halothane anesthesia and anesthesia/ovariohysterectomy did not significantly alter the plasma fentanyl concentrations achieved or pharmacokinetic parameters measured, when compared with awake cats. There was a high degree of individual variability observed both within and between groups of cats in parameters measured. Clinical significance The high degree of variability observed suggests that careful observation of cats with fentanyl patches in place is required to assess efficacy and any potential adverse effects. Anesthesia and anesthesia/ovariohysterectomy do not appear to alter plasma fentanyl concentrations achieved by placement of a 25 μg hour?1 transdermal fentanyl patch when compared to cats not undergoing these procedures.  相似文献   

3.
OBJECTIVE: To compare the efficacy of meloxicam administered perioperatively with transdermal administration of fentanyl via a patch placed preoperatively in dogs undergoing orthopedic surgery. DESIGN: Prospective study. ANIMALS: 16 dogs. PROCEDURE: Unilateral or bilateral osteotomy of the tibia and fibula was surgically performed, and a uniplanar external distraction device was placed in each limb. Postoperative pain and lameness were assessed 24, 48, and 72 hours after administration of the first of 3 doses of meloxicam (0.2 mg/kg [0.09 mg/lb], IV, given preoperatively, followed by 0.1 mg/kg [0.045 mg/lb], IV, after 24 hours, and 0.1 mg/kg, PO, after 48 hours) or preoperative placement of a transdermal fentanyl patch (50 microg/h) left in place for 72 hours. RESULTS: No significant differences in total pain scores were detected between groups. Mean +/- SD lameness scores assessed at 24 and 72 hours were lower in dogs in the meloxicam group than dogs in the fentanyl group. Lameness scores decreased with time in a similar manner in both treatment groups. CONCLUSIONS AND CLINICAL RELEVANCE: Perioperative administration of meloxicam or preoperative placement of a transdermal fentanyl patch provided effective and similar postoperative analgesia in dogs undergoing orthopedic surgery. However, because of its anti-inflammatory effects, treatment with meloxicam reduced the degree of lameness and resulted in rapid functional recovery of the limb.  相似文献   

4.
ObjectiveTo investigate the analgesic and side effects of epidural morphine or a fentanyl patch after ovariohysterectomy in dogs.Study designProspective, randomized clinical study.AnimalsTwenty female mongrel dogs undergoing ovariohysterectomy.MethodsThe dogs were allocated to one of two groups: epidural morphine or transdermal fentanyl patch. Anaesthesia was induced with propofol and maintained with isoflurane. Morphine (0.1 mg kg?1) was administered epidurally in the epidural morphine group and a transdermal fentanyl patch was applied 24 hours before the operation in the fentanyl patch group.The heart rate, respiratory rate, body temperature, plasma cortisol concentration, and sedation and analgesia scores were recorded during the 24 hour post-operative period. Adverse effects such as vomiting, anorexia, skin reactions, urinary retention, and time to start licking the surgical site were also recorded. p < 0.05 was considered significant. Statistical analyses utilized anova for repeated measures, Friedman tests, Mann-Whitney U-tests and independent sample t-tests as relevant.ResultsPain scores were lower in the epidural group than in the fentanyl group at all post-operative times. The dogs in the epidural morphine group were calm and relaxed, whereas discomfort and vocalization were recorded in the fentanyl patch group. The sedation scores were higher in the fentanyl patch group throughout the 12 hour period. Salivation and anorexia lasted longer in the fentanyl patch group than in the epidural morphine group. Plasma cortisol concentrations were high in the early post-operative period in both groups. The fentanyl patch group had higher cortisol concentrations than the epidural morphine group. Slight erythema was recorded in two dogs when the patches were removed.Conclusion and clinical relevanceEpidurally administered morphine provided better analgesia and caused fewer adverse effects than the fentanyl patch after ovariohysterectomy in dogs.  相似文献   

5.
OBJECTIVES: To determine whether transdermal fentanyl patches provided cost-effective post-operative analgesia in dogs with pelvic limb injuries. STUDY DESIGN: Prospective, randomized, blinded clinical trial. ANIMALS: Twenty-four dogs undergoing repair of ruptured cranial cruciate ligaments or pelvic limb fractures. METHODS: Dogs were randomly assigned to one of two groups: those receiving transdermal fentanyl patches (group F) and those receiving injectable morphine for control of post-operative pain (group M). Patients in both treatment groups were monitored for adequacy of analgesia and alterations in physiological variables. Plasma fentanyl concentrations were measured in Group F. Rescue morphine was given if a dog was deemed uncomfortable. The time of first rescue morphine, the total amount, and number of doses of morphine administered over 72 hours was quantified and compared for each group. RESULTS: There was no significant treatment effect on any of the parameters, except for serum cortisol concentration, which was significantly lower overall in group F (p = 0.01). Pain scores peaked at 6 hours post-extubation and were higher than baseline from 2 to 20 hours post-extubation. Cortisol concentrations were the highest at time 0 (extubation) and were significantly higher than baseline until 2 hours post-extubation. Pain scores correlated with fentanyl plasma concentrations (p = 0.0001 and p = 0.01, respectively), but the correlation was low (r = 0.26 and r = 0.16, respectively). No correlation was found between serum cortisol concentrations and pain scores in either group. Fentanyl cost and total cost for pain management were considerably higher for group F. CONCLUSIONS: Fentanyl patches did not provide better analgesia or a reduced requirement for rescue opioid compared with intramuscular morphine. CLINICAL RELEVANCE: When considering overall costs to the client for comparable analgesic intervention, fentanyl patches increased rather than decreased cost during the first 24 hours post-operatively.  相似文献   

6.
Fentanyl citrate is a potent opioid that can be delivered by the transdermal route in cats and dogs. Publications regarding transdermal fentanyl patches were obtained and systematically reviewed. Seven studies in cats and seven studies in dogs met the criteria for inclusion in this review. Dogs achieved effective plasma concentrations approximately 24 hours after patch application. Cats achieved effective plasma concentrations 7 hours after patch application. In dogs, transdermal fentanyl produced analgesia for up to 72 hours, except for the immediate 0- to 6-hour postoperative period. In cats, transdermal fentanyl produced analgesia equivalent to intermittent butorphanol administration for up to 72 hours following patch application.  相似文献   

7.
OBJECTIVE: To compare pharmacokinetic and pharmacodynamic characteristics of fentanyl citrate after IV or transdermal administration in cats. ANIMALS: 6 healthy adult cats with a mean weight of 3.78 kg. PROCEDURE: Each cat was given fentanyl IV (25 mg/cat; mean +/- SD dosage, 7.19 +/- 1.17 mg/kg of body weight) and via a transdermal patch (25 microg of fentanyl/h). Plasma concentrations of fentanyl were measured by use of radioimmunoassay. Pharmacokinetic analyses of plasma drug concentrations were conducted, using an automated curve-stripping process followed by nonlinear, least-squares regression. Transdermal delivery of drug was calculated by use of IV pharmacokinetic data. RESULTS: Plasma concentrations of fentanyl given IV decreased rapidly (mean elimination half-life, 2.35 +/- 0.57 hours). Mean +/- SEM calculated rate of transdermal delivery of fentanyl was 8.48 +/- 1.7 mg/h (< 36% of the theoretical 25 mg/h). Median steady-state concentration of fentanyl 12 to 100 hours after application of the transdermal patch was 1.58 ng/ml. Plasma concentrations of fentanyl < 1.0 ng/ml were detected in 4 of 6 cats 12 hours after patch application, 5 of 6 cats 18 and 24 hours after application, and 6 of 6 cats 36 hours after application. CONCLUSIONS AND CLINICAL RELEVANCE: In cats, transdermal administration provides sustained plasma concentrations of fentanyl citrate throughout a 5-day period. Variation of plasma drug concentrations with transdermal absorption for each cat was pronounced. Transdermal administration of fentanyl has potential for use in cats for long-term control of pain after surgery or chronic pain associated with cancer.  相似文献   

8.
OBJECTIVE: To evaluate the efficacy of the transdermal fentanyl patch in relieving perioperative pain and stress associated with ovariohysterectomy in cats. STUDY DESIGN: Prospective laboratory trial. ANIMALS: Twenty-four female, purpose-bred cats. METHODS: Each cat was randomly assigned to groups 1-3. Group 1 received a 25-microg/h transdermal fentanyl patch only. Group 2 received the patch and anesthesia. Group 3 received anesthesia only. Patches were left in place for 72 hours. Rectal temperature, heart rate, respiratory rate, indirect blood pressure, blood glucose, serum cortisol concentration, plasma fentanyl concentration, pain score, and excitement/sedation score were monitored at prescribed intervals over an 81-hour period. Cats from groups 1-3 were reassigned to groups 4 and 5. Group 4 received the patch, anesthesia, and an ovariohysterectomy. Group 5 received anesthesia and an ovariohysterectomy only. The study period and monitored parameters were the same as for groups 1-3. RESULTS: Serum cortisol concentrations were significantly lower in group 4 than group 5 during the surgical and early postsurgical time periods. A similar effect was noted in blood glucose concentrations during the surgical period. Rectal temperature was significantly higher in group 2 when comparing all anesthetized groups during the early postsurgical period. Pain scores were significantly higher in groups 4 and 5 than in groups 2 and 3 during the early postsurgical period. There was no significant difference in pain scores between groups 4 and 5 during this period, however. CONCLUSIONS: The transdermal fentanyl patch affects biochemical markers of perioperative pain and stress associated with ovariohysterectomy in cats, attenuating rises in serum cortisol and blood glucose concentrations during the surgical and early postsurgical periods. CLINICAL RELEVANCE: The transdermal fentanyl patch is effective in alleviating perioperative pain and stress associated with ovariohysterectomy in cats as evidenced by attenuated rises in cortisol and blood glucose concentrations in cats that were operated on and treated with the patch.  相似文献   

9.
Fentanyl is a potent mu opioid receptor agonist that was discovered to identify an improved human health analgesic over morphine, an opioid frequently associated with histamine-release, bradycardia, hyper- or hypotension, and prolonged postoperative respiratory depression. Historically, the pharmacological features of fentanyl have been described primarily through the study of the human approved fentanyl citrate formulation. In conscious dogs, fentanyl has a wide margin of safety, possesses minimum effects on the cardiovascular and respiratory systems, and is readily reversible. Other pharmacological features include sedation, mild reductions in body temperature, and dose-dependent reduction in food intake. The short duration of effect of available fentanyl citrate solutions has limited its clinical use to perioperative injections or constant rate infusions (CRIs). To extend the analgesic effect, additional fentanyl delivery technologies have been developed for human health including the fentanyl patch that has been used in an extra-label manner in dogs. Beyond the slow onset and variability in fentanyl delivery, several additional disadvantages have precluded common use of patches in dogs. The recent approval of long-acting transdermal fentanyl solution for dogs provides a new approach for sustained delivery of fentanyl for the control of postoperative pain in dogs. It has a rapid onset of action, prolonged duration, and mitigates the disadvantages of oral, parenteral, and patch-delivered opioids. The availability of a safe and effective approved opioid in dogs may allow further optimization of postoperative analgesia in this species. The objective of this review is to summarize the history and pharmacology of fentanyl and to integrate information about the newly approved long-acting transdermal fentanyl solution.  相似文献   

10.
OBJECTIVE: To determine whether the minimum alveolar concentration (MAC) of isoflurane was altered by transdermal administration of fentanyl in normothermic and hypothermic dogs. DESIGN: Randomized complete block crossover design. ANIMALS: 6 mature healthy dogs. PROCEDURE: Dogs received each of 4 treatments in random order. Following induction of anesthesia, normothermia was maintained in dogs that were treated with a fentanyl patch (F-NORM) or sham patch (C-NORM), or hypothermia was maintained in dogs that were treated with a fentanyl patch (F-HYPO) or sham patch (C-HYPO). The appropriate patch was applied 24 hours prior to induction of anesthesia. Anesthesia was induced with isoflurane in oxygen; the dogs were intubated and mechanically ventilated. Target esophageal temperatures were maintained within 1 degrees C of baseline values (normothermia) or at 34.5 degrees C (94.1 degrees F; hypothermia) for 1 hour prior to starting MAC determinations. Supramaximal stimulation was achieved with an electrical stimulator attached to needle electrodes placed in the buccal mucosa of the lower jaw of the dog. RESULTS: Mean MAC +/- SEM of isoflurane during C-NORM, C-HYPO, F-NORM, and F-HYPO treatments were 1.20 +/- 0.17, 0.89 +/- 0.18, 0.76 +/- 0.10, and 0.81 +/- 0.17, respectively. The mean MAC during C-NORM was significantly higher than values for the other treatments. There was no significant difference in mean MAC among the C-HYPO, F-NORM, and F-HYPO treatments. CONCLUSIONS AND CLINICAL RELEVANCE: Data suggest that transdermal administration of fentanyl significantly reduces isoflurane requirements in normothermic dogs. The isoflurane MAC-sparing effects of transdermal fentanyl are not apparent in hypothermic dogs.  相似文献   

11.
A prospective, double-blinded, positive-controlled, multicenter, noninferiority clinical study was conducted to evaluate the safety and effectiveness of a long-acting transdermal fentanyl solution (TFS) for the control of postoperative pain. Four hundred forty-five client-owned dogs of various breeds were randomly assigned to receive a single dose of TFS (2.6 mg/kg [～50 μL/kg]) (N = 223) applied 2-4 h prior to surgery or buprenorphine (20 μg/kg) (N = 222) administered intramuscularly 2-4 h prior to surgery and every 6 h through 90 h. There were 159 (35.7%) males and 286 (64.3%) females ranging from 0.5 to 16 years of age and 3 to 98.5 kg enrolled. Pain was scored using the modified Glasgow Composite Pain Scale with an a priori dropout criteria of ≥ 8 (20 maximum score). The one-sided upper 95% confidence interval of the mean difference between fentanyl and buprenorphine treatment failures was 5.6%, which was not greater than the a priori selected margin difference of 15%. Adverse events attributed to either treatment were minimal in impact and were approximately equal between groups. Sustained plasma fentanyl concentrations provided by a single pre-emptive dose of TFS are safe and effective and are noninferior to repeated injections of buprenorphine in controlling postoperative pain over 4?days. This long-acting fentanyl formulation provides veterinarians with a novel, registered option for the control of postoperative pain in dogs that improves dosing compliance and potentially mitigates the disadvantages of oral, parenteral, and patch delivered opioids.  相似文献   

12.
Recently, decreased activity levels have been observed in pigs treated postoperatively with transdermal delivery of fentanyl (TD-fentanyl) after isoflurane anaesthesia. Whether the change in behaviour is related to opioid-induced sedation or to insufficient pain relief remains to be investigated. This study was therefore undertaken to evaluate the effect of TD-fentanyl 50 microg h(-1) on the activity level with and without isoflurane anaesthesia. Eight pigs (25.4 +/- 5.2 kg) were submitted to a cross-over study and given two treatments; 1) fentanyl patch applied after 30 minutes of anaesthesia (treatment A/F) and 2) fentanyl patch without anaesthesia (treatment F). The pigs' behaviour was observed from a video recording instantaneously every 10 minutes for 24 h before treatments and up to 72 h after the patch attachment. Venous blood samples were taken 1, 6, 12, 24, 48 and 72 h after the patch application. The behaviour recordings showed that TD-fentanyl did not produce sedation in any pig. No differences were found between the two treatments in activity level, weight gain or serum fentanyl concentration. This concentration measured after 24 h was 0.27 +/- 0.11 ng ml(-1) and 0.47 +/- 0.40 ng ml(-1) in the A/F and F group, respectively. In conclusion, transdermal delivery of 50 microg h(-1) fentanyl did not cause inactivity in growing pigs. However, the large variations in serum fentanyl concentration indicate that drug absorption from transdermal patches is unpredictable and sometimes deficient.  相似文献   

13.
This study investigated the pharmcokinetics, efficacy, and safety of the fentanyl transdermal therapeutic system (TTS) in horses in which there was an inadequate analgesic response to nonsteroidal anti-inflammatory drugs (NSAIDs) alone. Nine horses with pain that was refractory to therapeutic doses of phenylbutazone (n = 3) or flunixin meglumine (n = 6) subsequently also received between 39 and 110 microg/kg of transdermal fentanyl. Blood samples were collected at 0, 1, 2, 3, 4, 5, 6, 12, 24, 36, 48, 60, and 72 hours after patch application, and a radioimmunoassay was used to determine serum fentanyl concentrations. Pharmacokinetic values were determined by noncompartmental analysis. Physical examination findings were recorded in all horses, and pain and lameness grading systems were used to assign scores to 8 and 6 horses, respectively. All horses tolerated the administration of fentanyl TTS, in that no clinically significant adverse effects attributable to fentanyl were observed. Use of the TTS resulted in variable serum concentrations of fentanyl, with a peak serum concentration of 2.2+/-1.1 ng/mL (mean+/-SD) and a time to peak serum concentration of 26+/-13 hours. After transdermal fentanyl administration, mean time to reach serum fentanyl concentrations consistent with analgesia in other species (1 ng/mL) was 14 hours. In addition, serum fentanyl concentrations of 1 ng/mL or greater were maintained in all but one horse for at least 18 hours. Pain scores were significantly decreased after fentanyl TTS and NSAID administration (P < .05), but lameness scores were not significantly different (P > .05). Overall, administration of fentanyl TTS had a favorable pharmacokinetic profile in horses with clinical pain, and the fentanyl TTS in combination with NSAIDs appeared to provide safe and effective analgesia in most of the horses with pain that was refractory to NSAID therapy alone.  相似文献   

14.
OBJECTIVE: To evaluate disposition of fentanyl in goats after IV and transdermal administration. ANIMALS: 8 healthy 2-year-old goats weighing 31.8 to 53.6 kg (mean+/-SD, 40.4+/-7.5 kg). PROCEDURE: Each goat was given 2 treatments consisting of fentanyl administered IV (2.5 microg/kg of body weight) and via a transdermal patch (50 microg/h). There was a 2-month interval between treatments. Blood samples were collected at specified times and analyzed in duplicate to determine plasma fentanyl concentrations. Pharmacokinetic values were calculated, using a computerized modeling program. RESULTS: Administration of fentanyl was tolerated by all goats. Intravenous administration of fentanyl resulted in a transitory increase in rectal temperature that was not clinically important. Terminal elimination half-life after IV administration was 1.20+/-0.78 h, volume of distribution at steady state was 1.51+/-0.39 L/kg, and systemic clearance was 2.09+/-0.62 L/kg/h. Transdermal administration of fentanyl resulted in variable plasma concentrations, with peak plasma concentrations ranging from 1.12 to 16.69 ng/ml (mean+/-SD, 6.99+/-6.03 ng/ml) and time to peak concentration ranging from 8 to 18 hours (mean+/-SD, 13+/-4.5 hours). After removal of the transdermal patch, mean+/-SD terminal elimination half-life was 5.34+/-5.34 hours. CONCLUSIONS AND CLINICAL RELEVANCE: Intravenous administration of fentanyl (2.5 microg/kg) in goats results in a relatively short half-life that will limit its use for management of pain. Transdermal administration of fentanyl (50 microg/h) in goats results in variable plasma concentrations that may exceed those anticipated on the basis of a theoretical delivery rate, but stable plasma concentrations of fentanyl may not be achieved.  相似文献   

15.
The purpose of the study was to determine pharmacokinetics of fentanyl after intravenous (i.v.) and transdermal (t.d.) administration to six adult alpacas. Fentanyl was administered i.v. (2 μg/kg) or t.d. (nominal dose: 2 μg kg?1 hr?1). Plasma concentrations were determined using liquid chromatography–mass spectrometry. Heart rate and respiratory rate were assessed. Extrapolated, zero‐time plasma fentanyl concentrations were 6.0 ng/ml (1.7–14.6 ng/ml) after i.v. administration, total plasma clearance was 1.10 L hr?1 kg?1 (0.75–1.40 L hr?1 kg?1), volumes of distribution were 0.30 L/kg (0.10–0.99 L/kg), 1.10 L/kg (0.70–2.96 L/kg) and 1.5 L/kg (0.8–3.5 L/kg) for V1, V2, and Vss, respectively. Elimination half‐life was 1.2 hr (0.5–4.3 hr). Mean residence time (range) after i.v. dosing was 1.30 hr (0.65–4.00 hr). After t.d. fentanyl administration, maximum plasma fentanyl concentration was 1.20 ng/ml (0.72–3.00 ng/ml), which occurred at 25 hr (8–48 hr) after patch placement. The area under the plasma fentanyl concentration‐vs‐time curve (extrapolated to infinity) after t.d. fentanyl was 61 ng*hr/ml (49–93 ng*hr/ml). The dose‐normalized bioavailability of fentanyl from t.d. fentanyl in alpacas was 35.5% (27–64%). Fentanyl absorption from the t.d. fentanyl patch into the central compartment occurred at a rate of approximately 50 μg/hr (29–81 μg/hr) between 8 and 72 hr after patch placement.  相似文献   

16.
Objective—To compare plasma fentanyl concentrations attained after the application of three transdermal fentanyl patch sizes (50, 75, and 100 μg/hour) in dogs. Design—Repeated Latin square controlled study. Animals—Six intact, mixed-breed adult dogs (2 males, 4 females) weighing 19.9 ± 3.4 kg. Methods—Each dog was randomly assigned to receive each of three treatments: 50 (P50), 75 (P75), or 100 (P100) μg/hour transdermal patches. Patches were left in place for 72 hours. Jugular venous blood was collected at 1,2, 4, 8, 12, 24, 36, 48, 60, and 72 hours after patch application and for 1, 2, 4, 8, and 12 hours after patch removal. Plasma fentanyl concentrations were measured using a radioimmunoassay technique. After a 96-hour washout period, each dog was moved to another treatment group and received a different patch size. Results—The following results were obtained (mean ± SD): average plasma fentanyl concentration from 24 to 72 hours, 0.7 ± 0.2 ng/mL (P50), 1.4 ± 0.5 ng/mL (P75), 1.2 ± 0.5 ng/mL (P100); the total area under the concentration versus time curve (0 hours to infinity), 46 ± 12.2 ng/h/mL (P50), 101.2 ± 41.4 ng/h/mL (P75), 80.4 ± 38.3 ng/h/mL (P100); and the apparent elimination half-life, 3.6 ± 1.2 hours (P50), 3.4 ± 2.7 hours (P75), and 2.5 ± 2.0 hours (P100). There was a high degree of variability in plasma fentanyl concentrations achieved. Plasma fentanyl concentrations declined rapidly after patch removal. Conclusions—The attainment of steady-state plasma concentrations takes up to 24 hours, and there is a great deal of variability in the final concentrations reached in different individuals. In this study, the 100 μg/hour patches did not provide statistically increased plasma concentrations when compared with the 50 μg/hour patches. Clinical Relevance—Because of the interindividual and intraindividual variation in plasma fentanyl concentrations, patches should be applied 24 hours before the anticipated time that analgesia will be required. Adequacy of analgesia and potentially deleterious side effects, such as sedation and respiratory depression, should be monitored while the patches are in place. Skin reactions may occur, and the patches should be removed if such skin irritation is seen. After the patch is removed, it is expected that analgesia will wane rapidly because of the brief elimination half-life.  相似文献   

17.
REASONS FOR PERFORMING STUDY: Although fentanyl has been reported to cause CNS excitation in horses, a transdermal therapeutic system (TTS) containing this mu agonist has recently been used empirically in equine medicine to treat moderate to severe pain. A better understanding of the disposition of fentanyl following transdermal administration would facilitate the clinical use of TTS fentanyl to obtain analgesia in horses. OBJECTIVES: To determine the pharmacokinetics of fentanyl following i.v. and TTS patch administration in healthy, mature horses and to evaluate the tolerance of horses to TTS fentanyl administration. METHODS: The pharmacokinetics of fentanyl in serum were assessed following a single i.v. dose, a single TTS dose, and multiple TTS doses in 6 healthy horses. Physical examinations, haematology and serum biochemistry analyses during transdermal fentanyl application were then performed to determine tolerance of continuous fentanyl administration. RESULTS: Fentanyl was very rapidly and completely absorbed following a single TTS dose. Mean serum fentanyl concentrations consistent with analgesia in other species were reached by 1 h and maintained until 32 h after patch application. Similar steady state serum concentrations were obtained when multiple doses of TTS fentanyl were administered every 48 or 72 h over 8 or 9 days, with less fluctuation in serum concentrations during the 48 h dosing interval. Three horses exhibited brief (< 12 h) episodes of increased body temperature; however, transdermal fentanyl administrations were not associated with other significant changes in haematology and biochemistry panels or physical examination findings. CONCLUSIONS AND POTENTIAL RELEVANCE: Although the pharmacodynamics of fentanyl have not been investigated fully in horses, transdermally-administered fentanyl exhibited a favourable pharmacokinetic profile without clinically relevant side effects and may be a useful analgesic in equine patients.  相似文献   

18.
A novel, long-acting transdermal fentanyl solution (TFS) that delivers sustained plasma fentanyl concentrations following a single application for the control of postoperative pain has recently been approved for use in dogs. The pharmacokinetics (PKs) of this formulation have been evaluated in healthy laboratory dogs, but they have not been reported in a clinical population of dogs for which it is indicated. Plasma fentanyl concentrations were determined from 215 dogs following a single, small-volume (～50 μL/kg) dose of TFS administered 2-4 h prior to orthopedic or soft tissue surgery. A population PK model was fit, and a 1-compartment open PK model with first-order absorption and an absorption lag-time best described the data. No tested clinical covariates had a significant effect on the PKs. The final model adequately described the population PKs and gave results consistent with laboratory PK studies in healthy dogs. The PKs were primarily characterized by a rapid initial increase in plasma fentanyl concentrations and a long terminal half-life of 74.0 (95% C.I. [54.7-113]) h governed by flip-flop kinetics for the typical subject. The plasma fentanyl concentrations were sustained over days in the range considered to be analgesic for postoperative pain in dogs.  相似文献   

19.
Objectives To determine whether moderate hypothermia during anesthesia significantly affects the serum concentration of transdermally delivered fentanyl and whether halothane or isoflurane affect these concentrations. Study Design Randomized cross‐over experimental trial. Animals Six mature, healthy Beagles (three males, three females) weighing 10.6 ± 0.43 kg. Methods A 50‐µg hour?1 fentanyl patch was applied 36 hours prior to anesthesia. Anesthesia was induced at time 0 (t = 0). Each dog received four treatments: isoflurane + normothermia (ISO‐NORM), isoflurane + hypothermia (ISO‐HYPO), halothane + normothermia (HAL‐NORM), and halothane + hypothermia (HAL‐HYPO). Dogs were intubated and maintained at 1.5 times MAC. Animals in the hypothermia treatments were cooled to 35 °C during anesthesia. Serum fentanyl analysis was performed at ?36, ?24, ?12, 0, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 6, 7, 8, 9, 10, 18, and 26 hours. Direct arterial blood pressures and arterial blood gases were monitored. Results The mean body temperatures (±SEM) during the anesthetic period for the four treatments were: ISO‐NORM = 37.7 ± 0.07 °C, ISO‐HYPO = 35.8 ± 0.1 °C, HAL‐NORM = 37.7 ± 0.06 °C, and HAL‐HYPO = 35.8 ± 0.13 °C. The mean (±SEM) serum fentanyl concentrations (SFC) for both hypothermia treatments were significantly lower than baseline concentrations at t = 1 hour and persisted for the duration of anesthesia for the ISO‐HYPO treatment but only from t = 1 to 2 hours for the HAL‐HYPO treatment. Serum fentanyl concentrations returned to baseline within one hour of the end of anesthesia, regardless of body temperature. There were no significant differences between treatments for systolic or diastolic blood pressure but mean blood pressures were higher during normothermia versus hypothermia during the last hour of anesthesia. Conclusions and clinical relevance Hypothermia during inhalation anesthesia produced a significant reduction in SFC using transdermal administration and was more protracted with isoflurane than halothane anesthesia. While significant reductions in SFC occurred, the SFC were still within the range believed to confer analgesia.  相似文献   

20.
OBJECTIVE: To compare plasma fentanyl concentrations and analgesic efficacy during full or partial exposure to 25-microg/h transdermal fentanyl patches (TFPs) in cats undergoing ovariohysterectomy. DESIGN: Randomized controlled clinical trial. ANIMALS: 16 client-owned cats. PROCEDURE: Cats were randomly assigned to receive full or partial exposure to a TFP; patches were applied approximately 24 hours prior to ovariohysterectomy. Rectal temperature, heart rate, respiratory rate, blood glucose concentration, and blood pressure were measured and pain severity was assessed periodically for 72 hours after patch application. Venous blood samples were collected for determination of plasma fentanyl concentration 0, 6, 12, 18, 24, 36, 48, 60, and 72 hours after patch application. RESULTS: Mean +/- SD steady state plasma fentanyl concentration in cats in the full TFP exposure group (1.78 +/- 0.92 ng/mL) was significantly greater than concentration in cats in the partial exposure group (1.14 +/- 0.86 ng/mL). Steady state plasma fentanyl concentrations were evident between 18 and 72 hours after patch application. Subjective scores used to evaluate analgesic efficacy were not significantly different between treatment groups. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that delivery of fentanyl from TFPs can be reduced by decreasing the amount of exposed surface area. In cats weighing < 4 kg (9 lb), exposure to half a 25-microg/h TFP appears to provide adequate analgesia following ovariohysterectomy.  相似文献   

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