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1.
Background: Signs of tachypnea after sedation of febrile horses with α2‐agonists have been noted previously but have not been further investigated. Objectives: To examine the effects of xylazine and detomidine on respiratory rate and rectal temperature in febrile horses and to investigate if either drug would be less likely than the other to cause changes in these variables. Animals: Nine febrile horses and 9 healthy horses were included in the study. Methods: Horses were randomly assigned to sedation with xylazine 0.5 mg/kg or detomidine 0.01 mg/kg. Heart rate and respiratory rate were recorded before sedation and at 1, 3, and 5 minutes after injection. Hourly measurements of rectal temperature were performed starting before sedation. Results: All febrile horses experienced an episode of tachypnea and antipyresis after sedation. Rectal temperature in the febrile group was significantly lower at 1, 2, and 3 hours after sedation. In several measurements, the decrease was >1°C. Respiratory rate in the febrile group was significantly increased after sedation. All febrile horses were breathing >40 breaths/min and 3 horses >100 breaths/min 5 minutes after sedation. No differences were noted between the 2 treatments. No significant changes in respiratory rate or temperature were noted in the reference group. Conclusions and Clinical Importance: Febrile horses can become tachypneic after sedation with detomidine or xylazine. The antipyretic properties of α2‐agonists need consideration when evaluating patients that have been sedated several hours before examination.  相似文献   

2.
Alpha2‐adrenoceptor agonists xylazine, romifidine, detomidine and, in some cases, medetomidine and dexmedetomidine, are fundamental drugs used in equine practice. There are situations where the undesirable pharmacodynamic effects (ataxia, prolonged sedation, bradycardia and ileus) or accidental overdose of these drugs may need to be antagonised. The α2‐adrenoceptor antagonists tolazoline, yohimbine and atipamezole can be used to antagonise undesirable effects. However, despite being effective, α2‐adrenoceptor antagonists are also not without undesirable pharmacodynamic effects. Excitement, muscle trembling and triggered inappropriate stress responses are a few of the more serious undesirable effects. Horses demonstrate a variable response to the antagonists thus recommending dose rates become fraught with difficulty. It is therefore recommended that the α2‐adrenoceptor antagonist should be titrated to the desired clinical effect. Consequently, other reversal agents, such as anticholinergics (atropine, glycopyrrolate and hyoscine), have been administered for the treatment of α2‐adrenoceptor agonist‐induced bradycardia. Anticholinergics cannot be recommended for routine use in horses due to the undesirable cardiovascular effects and potentiation of α2‐adrenoceptor agonist‐induced gastrointestinal hypomotility. Novel peripheral acting α2‐adrenoceptor antagonists, such as MK‐467, are currently under scrutiny in veterinary anaesthesia in an effort to antagonise the undesirable effects of α2‐adrenoceptor agonists without compromising on the level of sedation. This review examines the current literature on the α2‐adrenoceptor antagonists used in horses and makes recommendations on how to use these drugs safely in an attempt to prevent undesirable pharmacodynamic effects.  相似文献   

3.
Xylazine, the classical α2‐adrenoceptor (α2‐AR) agonist, is still used as an analgesic and sedative in veterinary medicine, despite its low potency and affinity for α2‐ARs. Previous pharmacological studies suggested that the α2A‐AR subtype plays a role in mediating the clinical effects of xylazine; however, these studies were hampered by the poor subtype‐selectivity of the antagonists used and a lack of knowledge of their bioavailability in vivo. Here, we attempted to elucidate the role of the α2A‐AR subtype in mediating the clinical effects of xylazine by comparing the analgesic and sedative effects of this drug in wild‐type mice with those in α2A‐AR functional knockout mice using the hot‐plate and open field tests, respectively. Hippocampal noradrenaline turnover in both mice was also measured to evaluate the contribution of α2A‐AR subtype to the inhibitory effect of xylazine on presynaptic noradrenaline release. In wild‐type mice, xylazine (10 or 30 mg/kg) increased the hot‐plate latency. Furthermore, xylazine (3 or 10 mg/kg) inhibited the open field locomotor activity and decreased hippocampal noradrenaline turnover. By contrast, all of these effects were abolished in α2A‐AR functional knockout mice. These results indicate that the α2A‐AR subtype is mainly responsible for the clinical effects of xylazine.  相似文献   

4.
Objective To study the analgesic potency of the α2‐agonist romifidine in the horse using both an electrical current and a mechanical pressure model for nociceptive threshold testing. In addition, a comparison was made with doses of detomidine and xylazine that produce equivalent degrees of sedation. Study design Randomized, placebo‐controlled, blinded cross‐over study. Animals Six adult Swiss warmblood horses, one mare and five geldings, weighing from 530 to 650 kg and aged 6–15 years. Methods Nociceptive thresholds were measured using an electrical stimulus applied to the coronary band and using a pneumatically operated pin pressing on the cannon bone. Measurements were made immediately before and every 15 minutes for 2 hours after IV injection of the test substances. Lifting of the foot indicated the test end point. Results The three α2‐agonists caused a temporary increase in nociceptive thresholds with a maximal effect within 15 minutes and a return to baseline levels within 1 hour. Using electrical current testing nociceptive thresholds were significantly different from placebo (mean ± SD) for detomidine at 15 minutes (from control 5.8 ± 0.9 to 23.3 ± 3.9 mA, p = 0.0066) and 30 minutes (from control 6.6 ± 1.1 to 18.8 ± 3.3 mA, p = 0.0091). The difference was significant for romifidine at 15 minutes only (from control 5.8 ± 0.9 to 18.7 ± 3.8 mA, p = 0.0066). With mechanical pressure testing nociceptive thresholds were significantly different from control for detomidine at 15 minutes (from 3.2 ± 0.2 to 6.2 ± 0.5 N, p = 0.00076) and 30 minutes (from 3.2 ± 0.7 to 5.7 ± 0.8 N, p = 0.0167). The difference was significant for xylazine at 15 minutes (from control 3.2 ± 0.2 to 5.6 ± 0.7 N, p = 0.0079). At 15 minutes the order of magnitude of the measured antinociceptive effect was significantly different between the two pain tests for both romifidine and detomidine, but not for xylazine. For romifidine, the increase of mean thresholds compared to placebo was 4.0 ± 1.3 times placebo levels with the electrical current test compared to 1.3 ± 0.3 times for the mechanical pressure test (p = 0.037). For detomidine, the increase of mean thresholds compared to placebo was 5.4 ± 1.7 times control levels with the electrical current test compared to 2.0 ± 0.2 times for the mechanical pressure test (p = 0.040). This represents a 2.7 (romifidine) and 3.4 times (detomidine) greater increase in thresholds using electrical current testing compared to the use of mechanical pressure testing. Conclusion and clinical relevance This study demonstrates the analgesic potential of α2‐agonists in the horse for somatic pain and that they can have quantitatively different antinociceptive effects according to the antinociceptive test used.  相似文献   

5.
The effects of selective α2-agonists (xylazine, detomidine and medetomidine) and antagonists (yohimbine and atipamezole) on in vitro small intestine motility in the horse were evaluated. Samples of equine jejunum were placed in isolated organ baths and drug-induced modifications of motility were measured by means of an isotonic transducer. All tested α2-agonists dose-dependently reduced both spontaneous and electrically-evoked phasic contractions. Conversely, α2-antagonists were ineffective when tested alone, and showed a heterogeneous and dose-independent ability to inhibit agonist activity. In particular, the antagonism exerted by higher concentrations of both yohimbine and atipamezole against α2-agonists was weaker than when lower concentrations were used. The data are indicative of the presence of both pre- and post-synaptic α2-adrenoceptors with inhibitory activity on equine jejunum motility, and support a possible therapeutic utility of these drugs in horse intestinal disorders associated with hypermotility.  相似文献   

6.
In the present study, the hypoxaemic potential of four α2 agonists possessing different selectivity for α2 adrenoceptors and of a saline placebo was studied in five clinically healthy sheep using a randomized Latin square design and equipotent sedative doses. Baseline values for heart rate (HR), mean arterial pressure (MAP), arterial oxygen (PaO2) and carbon dioxide (PaCO2) tensions, respiration rate and maximum change in pleural pressure (ΔPpl) were obtained, followed by the intravenous administration of either: xylazine (150 μg/kg); romifidine (50 μg/kg); detomidine (30 μg/kg); medetomidine (10 μg/kg) or placebo. Subsequent recordings were made up to 60 min after drug administration. No significant (P 0.05) alterations in any variable occurred with placebo. All the α2 agonists significantly (P 0.05) decreased PaO2 levels without a significant (P 0.05) change in PaCO2. The lowest PaO2 values were 29–42 mm Hg (3.9–5.5 kPa) with no significant difference between drugs. Respiratory rate and ΔPpl increased significantly within 2 min of drug administration; the duration of this effect varied with the α2 agonist, lasting longest with romifidine. As compared to the saline treated group, a significant increase in MAP was observed up to 10 min after administration of romifidine and detomidine, however, a significant decrease was seen at 10 and 45 min after xylazine and medetomidine, respectively. The α2 agonists studied induced a similar change in PaO2 at peak effect, despite their reported variable selectivity for α2 vs. α1 adrenoceptors.  相似文献   

7.
Four hundred and ninety horses were anaesthetised with halothane for clinical surgical or diagnostic procedures following induction with either detomidine/keta-mine, detomidine/thiopentone, xylazine/ketamine or guaiphenesin/thiopentone. Routine clinical monitoring was performed during anaesthesia. All horses developed hypotension (mean arterial pressures below 80 mm Hg) and respiratory depression (significant fall in respiratory rate and arterial carbon dioxide tension above 7 kPa (53 mm Hg)) consistent with the recognised effects of halothane. All anaesthetic procedures incorporating xylazine or detomidine resulted in lower pulse rates (28–35 per min) than after guaiphenesin/thiopentone (36–44 per min) and there was greater respiratory depression after techniques employing thiopentone rather than keta-mine. Development of hypotension was delayed after techniques using the α2 adrenoceptor agonist agents (xylazine and detomidine), particularly detomidine. Prernedication with acepromazine did not affect any of the physiological variables measured after techniques employing detomidine. Recovery to standing was fastest after xylazine/ketamine (31±1 min) and slowest after detomidine/thiopentone (53±2 min). Recovery quality was best after detomidine/thiopentone and all techniques employing an α2 adrenoceptor agonist agent resulted in smoother recovery than after guaiphenesin/thiopentone. This study demonstrates that most of the physiological effects of individual induction agents are overridden by the cardiovascular and respiratory depressant effects of halothane. The study also shows that detomidine is an acceptable sedative for use before general anaesthesia with halothane in horses.  相似文献   

8.
The purpose of this study was to examine whether freeze‐dried germinal vesicles (GV) can be matured in vitro after being injected into enucleated fresh oocytes in pigs as an alternative method for conservation of genetic resources. Although no reduction of the size of GV (p = .094), resveratrol treatment significantly enhanced the survival rates following GV transfer (GVT) (p < .001). Supplementation with 100 or 200 mmol/L trehalose in freeze‐drying medium significantly increased the proportions of GVs with intact nuclear membrane and DNA integrity compared with the control group. Following transfer of freeze‐dried GVs into enucleated fresh oocytes, the proportion of reconstructed oocytes reached the metaphase‐II stage (2.4% ± 1.4%) was significantly lower (p < .05) than that of the in vitro matured control group (83.2% ± 2.5%), it was comparable with the GVT control group (7.4% ± 2.7%). The rates of freeze‐dried GVs with intact nuclear membrane and DNA stored at ?20°C for 5 days were significantly higher (p < .05) than those at 4°C and room temperature. The rates of intact nuclear membrane and DNA in the freeze‐dried GV stored for 15 or 30 days at ?20, 4°C and RT were not significantly different. In conclusion, matured oocytes were produced derived from freeze‐dried GVs.  相似文献   

9.
ABSTRACT

Aim: To evaluate the sedative and clinical effects of I/V xylazine, detomidine, medetomidine and dexmedetomidine in miniature donkeys.

Methods: Seven clinically healthy, male adult miniature donkeys with a mean age of 6 years and weight of 105?kg, were assigned to five I/V treatments in a randomised, cross-over design. They received either 1.1?mg/kg xylazine, 20?μg/kg detomidine, 10?μg/kg medetomidine, 5?μg/kg dexmedetomidine or saline, with a washout period of ≥7 days. The degree of sedation was scored using a 4-point scale by three observers, and heart rate (HR), respiration rate (RR), rectal temperature and capillary refill time (CRT) were recorded immediately before and 5, 10, 15, 30, 60, 90 and 120 minutes after drug administration.

Results: All saline-treated donkeys showed no sedation at any time, whereas the donkeys treated with xylazine, detomidine, medetomidine and dexmedetomidine had mild or moderate sedation between 5 and 60 minutes after treatment, and no sedation after 90 minutes. All animals recovered from sedation without complication within 2 hours. The mean HR and RR of saline-treated donkeys did not change between 0 and 120 minutes after administration, but the mean HR and RR of donkeys treated with xylazine, detomidine, medetomidine and dexmedetomidine declined between 5 and 60 minutes after drug administration. The mean rectal temperature of all treated donkeys did not change between 0 and 120 minutes after administration. The CRT for all donkeys was ≤2 seconds at all times following each treatment.

Conclusions and clinical relevance: Administration of xylazine at 1.1?mg/kg, detomidine at 20?μg/kg, medetomidine at 10?μg/kg and dexmedetomidine at 5?μg/kg resulted in similar sedation in miniature donkeys. Therefore any of the studied drugs could be used for sedation in healthy miniature donkeys.  相似文献   

10.
The cardiovascular effects of medetomidine, detomidine, and xylazine in horses were studied. Fifteen horses, whose right carotid arteries had previously been surgically raised to a subcutaneous position during general anesthesia were used. Five horses each were given the following 8 treatments: an intravenous injection of 4 doses of medetomidine (3, 5, 7.5, and 10 microg/kg), 3 doses of detomidine (10, 20, and 40 microg/kg), and one dose of xylazine (1 mg/kg). Heart rate decreased, but not statistically significant. Atrio-ventricular block was observed following all treatments and prolonged with detomidine. Cardiac index (CI) and stroke volume (SV) were decreased with all treatments. The CI decreased to about 50% of baseline values for 5 min after 7.5 and 10 microg/kg medetomidine and 1 mg/kg xylazine, for 20 min after 20 microg/kg detomidine, and for 50 min after 40 microg/kg detomidine. All treatments produced an initial hypertension within 2 min of drug administration followed by a significant decrease in arterial blood pressure (ABP) in horses administered 3 to 7.5 microg/kg medetomidine and 1 mg/kg xylazine. Hypertension was significantly prolonged in 20 and 40 microg/kg detomidine. The hypotensive phase was not observed in 10 microg/kg medetomidine or detomidine. The changes in ABP were associated with an increase in peripheral vascular resistance. Respiratory rate was decreased for 40 to 120 min in 5, 7.5, and 10 microg/kg medetomidine and detomidine. The partial pressure of arterial oxygen decreased significantly in 10 microg/kg medetomidine and detomidine, while the partial pressure of arterial carbon dioxide did not change significantly. Medetomidine induced dose-dependent cardiovascular depression similar to detomidine. The cardiovascular effects of medetomidine and xylazine were not as prolonged as that of detomidine. KEY WORDS: cardiovascular effect, detomidine, equine, medetomidine, xylazine.  相似文献   

11.
This study determined the unbound fraction of the peripheral α2‐adrenoceptor antagonist MK‐467 alone and combined with medetomidine. MK‐467 (0.1, 1 and 10 μm ) was incubated in canine plasma with and without medetomidine (molar ratio 20:1), with human serum albumin (HSA) and with α1‐acid glycoprotein (AGP). Rapid equilibrium dialysis was used for the measurement of protein binding. All samples were analysed by liquid chromatography and tandem mass spectrometry to obtain the unbound fraction (fu) of MK‐467. Unbound fractions (fu) of MK‐467 in canine plasma (mean ± standard deviation) were 27.6 ± 3.5%, 26.6 ± 0.9% and 42.4 ± 1.2% at 0.1, 1.0 and 10 μm concentrations, respectively. In the presence of medetomidine, fu were 27.5 ± 0.4%, 26.6 ± 0.9% and 41.0 ± 2.4%. The fu of MK‐467 in HSA were 50.1 ± 2.5% at 0.1 μm , 49.4 ± 1.2% at 1.0 μm and 56.7 ± 0.5% at 10 μm . fu of MK‐467 in AGP was 56.3 ± 3.7% at 0.1 μm , 54.6 ± 5.6% at 1.0 μm and 65.3 ± 0.4% at 10 μm . Protein binding of MK‐467 was approximately 70% between 0.1 and 1.0 μm . Medetomidine had no apparent effect on the protein binding of MK‐467.  相似文献   

12.
α2-Adrenergic receptor agonists are widely used in veterinary medicine as sedative/hypnotic agents. Four pharmacological subtypes of the α2-adrenergic receptor (A, B, C and D) have been identified based primarily on differences in affinity for several drugs. The purpose of this study was to examine the affinities of the sedative agents, xylazine, detomidine and medetomidine at the four α2-adrenergic receptor subtypes. Saturation and inhibition binding curves were performed in membranes of tissues containing only one subtype of a2-adrenergic receptor. The KD for the α2-adrenergic receptor radioligand, [3H]-MK-912, in HT29 cells (α2A-), neonatal rat lung (α2B-), OK cells (α2C-) and PC12 cells transfected with RG20 (α2D-) were 0.38 ± 0.08 n m , 0.70 ± 0.5 n m , 0.07 ± 0.02 n m and 0.87 ± 0.03 n m , respectively. Detomidine and medetomidine had approximately a 100 fold higher affinity for all the α2-adrenergic receptors compared to xylazine but neither agonist displayed selectivity for the α2-adrenergic receptor subtypes. These data suggest that available sedative/hypnotic α2-adrenergic receptor agonists can not discriminate between the four known α2-adrenergic receptor subtypes.  相似文献   

13.
Currently, approaches to pain control in horses are a mixture of art and science. Recognition of overt pain behaviours, such as rolling, kicking at the abdomen, flank watching, lameness or blepharospasm, may be obvious; subtle signs of pain can include changes in facial expression or head position, location in the stall and response to palpation or human interaction. Nonsteroidal anti‐inflammatory drugs (i.e. phenylbutazone, flunixin meglumine and firocoxib), opioids (i.e. butorphanol, morphine and buprenorphine) and α2‐adrenergic agonists (i.e. xylazine, detomidine, romifidine and medetomidine) are the most commonly used therapeutic options. Multimodal therapy using constant‐rate infusions of lidocaine, ketamine and/or butorphanol has gained popularity for severe pain in hospitalised cases. Drugs targeting neuropathic pain, such as gabapentin, are increasingly used for conditions such as laminitis. Optimal strategies for management of pain are based upon severity and chronicity, including special considerations for use of intra‐articular or epidural delivery and therapy in foals. Strategies that aim to mitigate adverse effects associated with use of various analgesic agents are briefly discussed.  相似文献   

14.
At present there is no alternative to the use of a demand valve and pressurised oxygen for emergency ventilation in large animal field anaesthesia, therefore we aimed at providing a proof‐of‐principle of a small (2.5 l) commercial foot pump to provide emergency intermittent positive pressure ventilation (IPPV) in large animals. The study was performed during elective field anaesthesia for castration of 5 Haflinger stallions. Horses were premedicated with acepromazine i.m. after catheterisation of the jugular vein, further sedation was obtained with detomidine and butorphanol i.v. Anaesthesia was induced with ketamine and midazolam i.v. and maintained with a constant rate infusion of midazolam, ketamine and xylazine. After endotracheal intubation the foot pump, modified with a manually operated expiratory valve, was connected to the endotracheal tube and oxygen (6 l/min) was supplied. Anaesthesia was monitored using spirometry, respiratory gas analysis, pulse oximetry and arterial blood gas analysis. When arterial partial pressure of carbon dioxide (PaCO2) exceeded 6.65 kPa, IPPV was provided by 2–4 consecutive compressions of the pump aiming at a tidal volume of 10 ml/kg bwt. The PaCO2 was maintained at 6.18 ± 3.06 kPa (mean ± s.d.) with a respiratory rate of 4–10 breaths/min. The tidal volume was 2678–8300 ml with a peak inspiratory pressure of 24 ± 6.6 cmH2O and a mean minute volume of 68.5 ± 13 l/min. Inspired oxygen concentration ranged from 26–46% (36 ± 7%) and arterial partial pressure of oxygen from 8.38–11.03 kPa (10.1 ± 0.93 kPa). The modified foot pump enables the practitioner to provide IPPV to large animals in emergency situations.  相似文献   

15.
Alpha2 agonists have a significant role in epidural anaesthetic techniques. However, there are few reports regarding epidural administration of these drugs especially in small animals ( Greene et al. 1995; Keegan et al. 1995; Vesal et al. 1996 ). This study compared the haemodynamic effects of xylazine and medetomidine after epidural injection in dogs. Six dogs (four females and two males) weighing 27.5 ± 3.39 kg, aged 5.6 ± 1.42 years were studied on two separate occasions one month apart. Dogs were sedated with 0.5 mg kg?1 diazepam IM and 0.1 mg kg?1 acepromazine IM. After 20 minutes, a lumbosacral epidural injection of 0.25 mg kg?1 xylazine was administered (group X). One month later, following the same sedation, 15 µg kg?1 medetomidine was administered epidurally (group M). Haemodynamic variables (ECG and indirect blood pressure (Doppler)), respiratory rate and rectal temperature were recorded before (baseline) and then every 5 minutes after the epidural injection, up to 60 minutes. Differences between groups were compared by a paired t‐test. Within group changes were compared to basal values by anova . A p‐value of < 0.05 was considered statistically significant. Both groups showed significant reductions in heart rate (106.3 ± 7.7 beats minute?1 baseline versus 67.7 ± 7.6 (group M); 91 ± 3.8 baseline versus 52.3 ± 9 (group X)) and mean arterial blood pressure (113.1 ± 12.3 mm Hg baseline versus 87 ± 11 (group M); 118 ± 7 baseline versus 91 ± 14 (group X)). There were no differences between groups in these variables. After epidural injection, first degree atrioventricular block was recorded significantly more often in group X (50% against 33%) but second degree block was significantly more frequent in group M (66% against 33%). Also 50% of dogs in group X and 66% in group M showed sinus arrest. Respiratory rate decreased significantly in both groups following the epidural injection (20.66 ± 0.66 minute?1 baseline versus 16.33 ± 4.77 (group M); 37.66 ± 0.56 baseline versus 16.33 ± 1.81 group X), but no differences between groups were observed. Rectal temperature decreased significantly in group X (38.16 ± 0.21) with respect to the basal measurement (39.30 ± 0.14 °C). In group M, there was no significant reduction in temperature, however, no statistical difference in rectal temperature was found between groups. This study shows that 0.25 mg kg?1 xylazine and 15 µg kg?1 medetomidine produce similar, significant cardiovascular and respiratory changes following lumbosacral epidural administration in dogs.  相似文献   

16.
To effectively control bovine mastitis, tilmicosin (TIL)‐ and florfenicol (FF)‐loaded solid lipid nanoparticles (SLN) with hydrogenated castor oil (HCO) were prepared by a hot homogenization and ultrasonication method. In vitro antibacterial activity, properties, and pharmacokinetics of the TIL‐FF‐SLN were studied. The results demonstrated that TIL and FF had a synergistic or additive antibacterial activity against Streptococcus dysgalactiae, Streptococcus uberis, and Streptococcus agalactiae. The size, polydispersity index, and zeta potential of nanoparticles were 289.1 ± 13.7 nm, 0.31 ± 0.05, and ?26.7 ± 1.3 mV, respectively. The encapsulation efficiencies for TIL and FF were 62.3 ± 5.9% and 85.1 ± 5.2%, and the loading capacities for TIL and FF were 8.2 ± 0.6% and 3.3 ± 0.2%, respectively. The TIL‐FF‐SLN showed no irritation in the injection site and sustained release in vitro. After medication, TIL and FF could maintain about 0.1 μg/mL for 122 and 6 h. Compared to the control solution, the SLN increased the area under the concentration–time curve (AUC0‐t), elimination half‐life (T½ke), and mean residence time (MRT) of TIL by 33.09‐, 23.29‐, and 37.53‐fold, and 1.69‐, 5.00‐, and 3.83‐fold for FF, respectively. These results of this exploratory study suggest that the HCO‐SLN could be a useful system for the delivery of TIL and FF for bovine mastitis therapy.  相似文献   

17.
In this study, heart and respiratory rates, cloacal temperature, and quality of sedation were evaluated before (0 min) and after (10, 20, and 30 min) i.m. administration of xylazine (10 mg/kg; n = 7), medetomidine (75 li; n = 6), detcmidine (0.3 mg/kg; n = 6), or diazepam (6 mg/kg; n = 7) in rock partridges (Alectoris graeca). All partridges recovered from sedation without any disturbance. Xylazine and diazepam administration did not induce significant changes in heart rate, which did decrease significantly after medetomidine and detomidine administration (P < 0.001). Mean respiratory rate was decreased dramatically at 20 and 30 min after xylazine (P < 0.001) and medetomidine (P < 0.005) administration, and at all stages of sedation after detomidine injection (P < 0.001), whereas there was not any significant change after diazepam injection. In all groups, cloacal temperature measured at 10, 20, and 30 min tended to decrease compared with baseline values. Sedative effects of the drugs started within 2.1+/-0.2 min for detomidine, 2.6 +/- 0.4 min for diazepam, 3.1 -+/-.4 min for xylazine, and 4.8+/-0.8 min for medetomidine application. There was an extreme variability in time to recovery for each drug: 205 +/-22.2 min for xylazine, 95 -12.2 min for medetomidine, 260+/-17.6 min for detomidine, and 149 + 8.3 min for diazepam. In conclusion, xylazine, medetomidine, detomidine, and diazepam produced sedation, which could permit some clinical procedures such as handling and radiographic examination of partridges to occur. Of the four drugs, xylazine produced stronger and more efficient sedation compared to the others, which could permit only minor procedures to be performed. However, depending on the drug used, monitoring of heart and respiratory rates and cloacal temperature might be required.  相似文献   

18.
ObjectiveTo evaluate the effects of intravenous (IV) or intramuscular (IM) hyoscine premedication on physiologic variables following IV administration of medetomidine in horses.Study designRandomized, crossover experimental study.AnimalsEight healthy crossbred horses weighing 330 ± 39 kg and aged 7 ± 4 years.MethodsBaseline measurements of heart rate (HR), cardiac index (CI), respiratory rate, systemic vascular resistance (SVR), percentage of patients with second degree atrioventricular (2oAV) block, mean arterial pressure (MAP), pH, and arterial partial pressures of carbon dioxide (PaCO2) and oxygen (PaO2) were obtained 5 minutes before administration of IV hyoscine (0.14 mg kg?1; group HIV), IM hyoscine (0.3 mg kg?1; group HIM), or an equal volume of physiologic saline IV (group C). Five minutes later, medetomidine (7.5 μg kg?1) was administered IV and measurements were recorded at various time points for 130 minutes.ResultsMedetomidine induced bradycardia, 2oAV blocks and increased SVR immediately after administration, without significant changes in CI or MAP in C. Hyoscine administration induced tachycardia and hypertension, and decreased the percentage of 2oAV blocks induced by medetomidine. Peak HR and MAP were higher in HIV than HIM at 88 ± 18 beats minute?1 and 241 ± 37 mmHg versus 65 ± 16 beats minute?1 and 192 ± 38 mmHg, respectively. CI was increased significantly in HIV (p ≤ 0.05). Respiratory rate decreased significantly in all groups during the recording period. pH, PaCO2 and PaO2 were not significantly changed by administration of medetomidine with or without hyoscine.Conclusion and clinical relevanceHyoscine administered IV or IM before medetomidine in horses resulted in tachycardia and hypertension under the conditions of this study. The significance of these changes, and responses to other dose rates, requires further investigation.  相似文献   

19.
Purpose These studies examined corneal healing rates, Type‐IV collagen and zonula occludens membrane‐associated protein (ZO‐1) expression, as well as aqueous PGE2 and IL‐1β concentrations in pigmented rabbits treated with either moxifloxacin 0.5%, gatifloxacin 0.3% or BSS® following anterior keratectomy. Methods Anterior keratectomy surgery was followed by topical administration with commercial ophthalmic formulations of either moxifloxacin or gatifloxacin or BSS® (TID for 96 h). Images of the fluorescein‐stained healing corneas were analyzed for wound area. At 48 or 96 h following surgery, aqueous humor samples were collected and analyzed for the inflammatory mediators PGE2 and IL‐1β using an ELISA. The corneas were subsequently evaluated using both scanning and transmission electron microscopy. In a second parallel study, corneas were evaluated at both 48 and 96 h for Type‐IV collagen and ZO‐1 expression using immunohistochemistry. Results Fluorescein‐stained corneal images at 96 h postsurgery demonstrated that 90% ± 8% re‐epithelialization for moxifloxacin, 81% ± 14% for gatifloxacin, and 88 ± 6% for BSS® (P > 0.05). PGE2 levels in the aqueous humor of fluoroquinolone treated eyes were reduced at 48 h compared to BSS® treated eyes. IL‐1β was undetectable in all samples. No differences in Type‐IV collagen or ZO‐1 expression were observed between any treatment groups. There were no differences between groups in histological appearance or in ultrastructural healing processes. Conclusions These studies demonstrated that the commercial ophthalmic formulations of moxifloxacin and gatifloxacin were similar to each other in their effects on the levels of aqueous humor PGE2 and rates of corneal wound re‐epithelialization.  相似文献   

20.
The present study aims to comparatively evaluate the effects of different doses of intravenous xylazine and medetomidine on sedation and antinociception scores, and physiological and laboratory parameters in dromedary calves. Thirty clinically healthy male dromedary calves 15 ± 2 weeks old and weighing 95 ± 5.5 kg were studied. Two groups received xylazine at low (0.2 mg/kg) and high (0.4 mg/kg) doses. Two groups received medetomidine at low (10 µg/kg) and high (20 µg/kg) doses. One group received normal saline. Sedation signs were scored using a 3‐point scale. Analgesic effect was analyzed using pinpricks. Data were analyzed by one‐way ANOVA and Mann–Whitney U‐tests. Sedation and antinociception scores of the animals 1 hr after receiving the higher dose of xylazine and medetomidine were significantly higher than that of other groups. Compared with other studied groups, the animals receiving the higher dose of xylazine showed significantly higher potassium and creatinine serum levels after 24 hr. Doses as high as 0.4 mg/kg for xylazine and 20 µg/kg for medetomidine can be considered safe and useful for procedures associated with mild pain in dromedary calves.  相似文献   

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