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1.
The cardiovascular effects of detomidine and xylazine were compared in six chronically instrumented, conscious ponies. Ponies were instrumented with a micromanometer in the left ventricular chamber, a Doppler flow probe on a coronary artery and sonomicrometer crystals in the left ventricular free wall. Heart rate, ventricular systolic pressure, stroke work, dP/dtmax, minute work and coronary blood flow were measured for 4 h following intravenous injection of detomidine at several doses or xylazine at 1.1 mg/kg. Both drugs caused a profound hypertensive response at 15 s post-injection. The magnitude of the pressure change did not increase with detomidine doses greater than 20 micrograms/kg. There was a dose-dependent effect on the duration of the hypertension. Bradycardia and A-V blockade of similar magnitude followed the hypertension at all drug doses. Both drugs caused a negative inotropic effect on the heart at all doses. Minute work, a mechanical index of myocardial O2 demand, and coronary flow decreased to a similar extent following all drug treatments. With the exception of a greater hypertensive response, detomidine at the dosages studied, produced cardiovascular effects that were very similar to those of the recommended dosage of xylazine.  相似文献   

2.
The effects of two intravenous doses of romifidine (80 and 120 microg/kg) and one dose of detomidine (20 microg/kg) were compared in a blinded study in 30 horses requiring to be sedated for routine dental treatment. Several physiological parameters were assessed before and for two hours after the administration of the drugs, and the horses' teeth were rasped 30 minutes after they were administered. Romifidine produced a dose-dependent effect on most parameters. Detomidine at 20 microg/kg was similar to romifidine at 120 microg/kg in the magnitude of its sedative effects, but was similar to romifidine at 80 pg/kg in its duration. There were no significant differences between the three treatments in terms of the clinical procedure score.  相似文献   

3.
Sedative effects of medetomidine, a potent selective and specific alpha 2-adrenoceptor agonist, were evaluated in pigs using 5 different doses (30, 50, 80, 100 and 150 micrograms/kg of body weight) and compared with those of xylazine (2 mg/kg). Atropine (25 micrograms/kg) was mixed with both drugs to prevent severe bradycardia. All drugs were administered intramuscularly. Medetomidine at a dosage of 30 micrograms/kg produced more potent sedation than xylazine. The depth of sedation induced by medetomidine was dose dependent within the range from 30 to 80 micrograms/kg. At 100 or 150 micrograms/kg, the depth of sedation was mostly the similar level to that at 80 micrograms/kg but the duration was prolonged. The degree of muscle relaxation produced by medetomidine also seemed to be dose dependent from 30 to 80 micrograms/kg and was stronger than that produced by xylazine. An increase in the duration of muscle relaxation was dose dependent up to 150 micrograms/kg. No analgesic effect was produced by xylazine, however moderate analgesia was obtained by medetomidine. There were no marked changes in heart rate and respiratory rate during the observation period in pigs of any groups, however mild hypothermia after the administration of both drugs was observed. From these results, medetomidine has a significant and dose-dependent sedative effects which are much more potent than that of xylazine, and a combination of 80 micrograms/kg of medetomidine and 25 micrograms/kg of atropine is suitable for sedation with lateral recumbency and moderate muscle relaxation without notable side effects in pigs.  相似文献   

4.
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   

5.
The sedative effects in horses of the new alpha 2 agonist medetomidine were compared with those of xylazine. Four ponies and one horse were treated on separate occasions with two doses of medetomidine (5 micrograms/kg bodyweight and 10 micrograms/kg bodyweight) and with one dose of xylazine (1 mg/kg bodyweight) given by intravenous injection. Medetomidine at 10 micrograms/kg was similar to 1 mg/kg xylazine in its sedative effect but produced more severe and more prolonged ataxia, and one animal fell over during the study. Medetomidine at 5 micrograms/kg produced less sedation but a similar degree of ataxia to 1 mg/kg xylazine.  相似文献   

6.
ObjectiveTo evaluate and compare the antinociceptive effects of the three alpha-2 agonists, detomidine, romifidine and xylazine at doses considered equipotent for sedation, using the nociceptive withdrawal reflex (NWR) and temporal summation model in standing horses.Study designProspective, blinded, randomized cross-over study.AnimalsTen healthy adult horses weighing 527–645 kg and aged 11–21 years old.MethodsElectrical stimulation was applied to the digital nerves to evoke NWR and temporal summation in the left thoracic limb and pelvic limb of each horse. Electromyographic reflex activity was recorded from the common digital extensor and the cranial tibial muscles. After baseline measurements a single bolus dose of detomidine, 0.02 mg kg?1, romifidine 0.08 mg kg?1, or xylazine, 1 mg kg?1, was administered intravenously (IV). Determinations of NWR and temporal summation thresholds were repeated at 10, 20, 30, 40, 60, 70, 90, 100, 120 and 130 minutes after test-drug administration alternating the thoracic limb and the pelvic limb. Depth of sedation was assessed before measurements at each time point. Behavioural reaction was observed and recorded following each stimulation.ResultsThe administration of detomidine, romifidine and xylazine significantly increased the current intensities necessary to evoke NWR and temporal summation in thoracic limbs and pelvic limbs of all horses compared with baseline. Xylazine increased NWR thresholds over baseline values for 60 minutes, while detomidine and romifidine increased NWR thresholds over baseline for 100 and 120 minutes, respectively. Temporal summation thresholds were significantly increased for 40, 70 and 130 minutes after xylazine, detomidine and romifidine, respectively.Conclusions and clinical relevanceDetomidine, romifidine and xylazine, administered IV at doses considered equipotent for sedation, significantly increased NWR and temporal summation thresholds, used as a measure of antinociceptive activity. The extent of maximal increase of NWR and temporal summation thresholds was comparable, while the duration of action was drug-specific.  相似文献   

7.
A controlled trial was conducted to assess suitability of combinations of medetomidine and ketamine for the ovariectomy of cats, to investigate the possible side effects, and to compare medetomidine/ketamine with a combination of xylazine and ketamine. Three hundred and thirty-seven cats were submitted to surgery; 100 were anaesthetised with 80 micrograms/kg medetomidine and 5 mg/kg ketamine, 137 with 80 micrograms/kg medetomidine and 7.5 mg/kg ketamine, and 100 were anaesthetised with 1 mg/kg xylazine and 10 mg/kg ketamine. The combinations were injected intramuscularly in the same syringe. The anaesthesia provided by the medetomidine/ketamine combinations was characterised by good muscle relaxation, good analgesia and minimal side effects. The only difference between the two doses of ketamine was the length of the period of anaesthesia. The advantages of the medetomidine/ketamine combination in comparison with xylazine/ketamine were the need for a lower dose of ketamine, a longer duration of action and better analgesia. Similar side effects were observed with both medetomidine/ketamine and xylazine/ketamine combinations.  相似文献   

8.
This study was designed to assess the effects of 5 anesthetic drug combinations in ponies: (1) ketamine 2.75 mg/kg, xylazine 1.0 mg/kg (KX), (2) Telazol 1.65 mg/kg, xylazine 1.0 mg/kg (TX), (3) Telazol 2 mg/kg, detomidine 20 micrograms/kg (TD-20), (4) Telazol 2 mg/kg, detomidine 40 micrograms/kg (TD-40), (5) Telazol 3 mg/kg, detomidine 60 micrograms/kg (TD-60). All drugs were given iv with xylazine or detomidine preceding ketamine or Telazol by 5 min. Heart rate was decreased significantly from 5 min to arousal after TD-20 but only at 60 and 90 min after TD-40 and TD-60 respectively. Respiratory rate was decreased significantly for all ponies. Induction time did not differ between treatments. Duration of analgesia was 10 min for KX, 22.2 min for TX, 27.5 min for TD-20, 32.5 min for TD-40, and 70 min for TD-60. Arousal time was significantly longer with detomidine and Telazol. Smoothness of recovery was judged best in ponies receiving KX and TD-40. All ponies stood unassisted 30 min after signs of arousal.  相似文献   

9.
OBJECTIVE: To determine sedative, cardiorespiratory and metabolic effects of xylazine hydrochloride, detomidine hydrochloride, and a combination of xylazine and acepromazine administered i.v. at twice the standard doses in Thoroughbred horses recuperating from a brief period of maximal exercise. ANIMALS: 6 adult Thoroughbreds. PROCEDURE: Horses were preconditioned by exercising them on a treadmill to establish a uniform level of fitness. Each horse ran 4 simulated races, with a minimum of 14 days between races. Simulated races were run at a treadmill speed that caused horses to exercise at 120% of their maximal oxygen consumption. Horses ran until they were fatigued or for a maximum of 2 minutes. One minute after the end of exercise, horses were treated i.v. with xylazine (2.2 mg/kg of body weight), detomidine (0.04 mg/kg), a combination of xylazine (2.2 mg/kg) and acepromazine (0.04 mg/kg), or saline (0.9% NaCl) solution. Treatments were randomized so that each horse received each treatment once, in random order. Cardiopulmonary indices were measured, and samples of arterial and venous blood were collected immediately before and at specific times for 90 minutes after the end of each race. RESULTS: All sedatives produced effective sedation. The cardiopulmonary depression that was induced was qualitatively similar to that induced by administration of these sedatives to resting horses and was not severe. Sedative administration after exercise prolonged the exercise-induced increase in body temperature. CONCLUSIONS AND CLINICAL RELEVANCE: Administration of xylazine, detomidine, or a combination of xylazine-acepromazine at twice the standard doses produced safe and effective sedation in horses that had just undergone a brief, intense bout of exercise.  相似文献   

10.
Comparison of the effects of xylazine and romifidine administered perioperatively on the recovery of anesthetized horses. The present study was designed to compare recoveries from anesthesia following the use of romifidine or xylazine in horses. In a prospective blind randomized clinical trial, 28 horses, undergoing elective arthroscopy, were randomly allocated into 2 groups. The intravenous anesthesia protocol used in the xylazine group was: butorphanol [0.02 mg/kg body weight (BW)] and xylazine (0.5 to 0.7 mg/kg BW) for premedication, diazepam (0.1 mg/kg BW) and ketamine (2.2 mg/kg BW) for induction, isoflurane in oxygen for maintenance and xylazine (0.1 mg/kg BW) in recovery. The xylazine was replaced with romifidine 0.05 to 0.08 mg/kg BW (premedication) and 0.01 mg/kg BW (recovery) in the romifidine group. The quality of recovery was evaluated with a modified scoring system and the duration recorded. Wilcoxon Ranked Sum test (P < 0.05) was used for statistical analysis. The recovery quality scores and the durations of recovery were not statistically different between the 2 groups. In this study, romifidine and xylazine were equal in their effects on recovery qualities.(Translated by the authors).  相似文献   

11.
The cardiovascular changes associated with anesthesia induced and maintained with romifidine/ketamine versus xylazine/ ketamine were compared using 6 horses in a cross over design. Anesthesia was induced and maintained with romifidine (100 microg/kg, IV)/ketamine (2.0 mg/kg, IV) and ketamine (0.1 mg/kg/min, IV), respectively, in horses assigned to the romifidine/ ketamine group. Horses assigned to the xylazine/ketamine group had anesthesia induced and maintained with xylazine (1.0 mg/kg, IV)/ketamine (2.0 mg/kg, IV) and a combination of xylazine (0.05 mg/kg/min, IV) and ketamine (0.1 mg/kg/min, IV), respectively. Cardiopulmonary variables were measured at intervals up to 40 min after induction. All horses showed effective sedation following intravenous romifidine or xylazine and achieved recumbency after ketamine administration. There were no significant differences between groups in heart rate, arterial oxygen partial pressures, arterial carbon dioxide partial pressures, cardiac index, stroke index, oxygen delivery, oxygen utilization, systemic vascular resistance, left ventricular work, or any of the measured systemic arterial blood pressures. Cardiac index and left ventricular work fell significantly from baseline while systemic vascular resistance increased from baseline in both groups. The oxygen utilization ratio was higher in the xylazine group at 5 and 15 min after induction. In conclusion, the combination of romifidine/ketamine results in similar cardiopulmonary alterations as a xylazine/ketamine regime, and is a suitable alternative for clinical anesthesia of the horse from a cardiopulmonary viewpoint.  相似文献   

12.
Intramuscular (i.m.) and intravenous (i.v.) administration of detomidine at doses of 10, 20 and 40 micrograms/kg body mass was evaluated for its sedative and analgesic properties in 15 goats (Capra hircus). The drug produced dose- and route-dependent sedation. The 10 micrograms/kg dose was effective only when administered i.v. There was no observable analgesia at this dose. Higher doses produced effective sedation and moderate analgesia of the body with either route of administration. Severe ataxia and sternal recumbency were seen in all the animals after the dose of 40 micrograms/kg. Other effects of detomidine in these goats included mild to moderate salivation, depressed respiratory rate, decreased rectal temperature, bradycardia and hyperglycaemia. Plasma concentrations of total protein, sodium, potassium and chloride were not affected.  相似文献   

13.
The effects of premedication with four different intravenous doses of romifidine (20, 40, 80 and 120 (μg/kg body weight) and a saline placebo were compared in a group of 20 adult beagles of both sexes, undergoing anaesthesia with propofol for a clinical dental procedure. Anaesthesia was induced 10 minutes after premedication and maintained by intravenous infusion of propofol for a period of 30 minutes. Romifidine had a marked synergistic effect with propofol and reduced the required induction and infusion doses by more than 60 per cent for a standard level of anaesthesia; the synergistic effect was dose related. Following premedication, propofol produced no significant alteration of respiratory rate, heart rate or rectal temperature. Anaesthesia was found to be more stable following romifidine premedication at all doses studied. The quality of induction was unaltered by the dose of the romifidine. Recovery from anaesthesia was smooth and of a similar quality in all cases. There were no differences in the recovery times between the unpremedicated group and the dogs premedicated with any dose of romifidine studied. There were no adverse effects noted following this anaesthetic regimen. The marked dose-related synergism with propofol induction and infusion anaesthesia is relevant should romifidine be used in the dog in clinical veterinary practice.  相似文献   

14.
OBJECTIVE: To evaluate the sedative, analgesic, and cardiorespiratory effects of intramascular (IM) romifidine in cats. STUDY DESIGN: Prospective, randomized experimental trial. ANIMALS: Ten healthy adult cats. METHODS: Romifidine (100, 200, and 400 microg kg(-1)) or xylazine (1 mg kg(-1)) was given IM in a cross-over study design. Heart rate (HR), respiratory rate (RR), rectal temperature (RT), hemoglobin saturation, oscillometric arterial pressure, and scores for sedation, muscle relaxation, position, auditory response, and analgesia were determined before and after drug administration. Time to recumbency, duration of recumbency, and time to recover from sedation were determined. Subjective evaluation and cardiorespiratory variables were recorded before and at regular intervals for 60 minutes after drug administration. RESULTS: Bradycardia developed in all cats that were given romifidine or xylazine. No other significant differences in physiologic parameters were observed from baseline values or between treatments. Increasing the dose of romifidine did not result in increased sedation or muscle relaxation. Cats given xylazine showed higher sedation and muscle relaxation scores over time. Analgesia scores were significantly higher after administration of romifidine (400 microg kg(-1)) and xylazine (1 mg kg(-1)) than after romifidine at 100 or 200 microg kg(-1). Duration of lateral recumbency was not significantly different between treatments; however, cats took longer to recover after administration of 400 micro g kg(-1) romifidine. CONCLUSIONS AND CLINICAL RELEVANCE: Bradycardia is the most important adverse effect after IM administration of romifidine at doses ranging from 100 to 400 microg kg(-1) or 1 mg kg(-1) of xylazine in cats. The sedative effects of romifidine at 200 microg kg(-1) are comparable to those of 1 mg kg(-1) of xylazine, although muscle relaxation and analgesia were significantly less with romifidine than with xylazine.  相似文献   

15.
Detomidine administered intramuscularly at a dose of 10, 20 or 40 micrograms/kg body mass was evaluated for its sedative effects in 15 unfasted infant calves (age: 15-20 days; body mass: 18-33 kg). The drug produced dose-dependent sedation. At a dose of 10 micrograms/kg detomidine produced effective sedation for 30 to 45 min without any observable analgesia. At doses of 20 or 40 micrograms/kg it caused deep sedation, sternal recumbency, and moderate analgesia of the trunk. Hyperglycaemia was recorded at all dose levels. The changes in respiratory rate, rectal temperature, haemoglobin, packed cell volume, total erythrocyte count and plasma concentration of total protein were not significant.  相似文献   

16.
The motor responses of the caecum and colon to stimulation of alpha 2-adrenoceptors by xylazine and detomidine at the recommended dose levels of 0.6 and 0.1 mg/kg were investigated in three ponies. The motor changes of the left ventral colon induced by continuous intra-arterial infusion of a prostaglandin (PGF2 alpha) were used to assess the relative inhibitory effects of xylazine and detomidine in a colic model. The administration of alpha 2-agonists inhibited the spiking activity on the whole of the large intestine for 20-30 min (xylazine) or 2-3 h (detomidine). However, the detomidine-induced inhibition was preceded by a short period of increased smooth muscle basal tone as indicated by strain-gauge force transducer measurements. This pattern of activity was neither reversed nor prevented by the administration of tolazoline (10 micrograms/kg/min) intra-arterially. In contrast, inhibition of the colonic phasic and tonic motor activity by alpha 2-adrenoceptor stimulation was reversed competitively by tolazoline. The intra-arterial infusion of prostaglandin F2 alpha (10 micrograms/kg/min) induced prolonged and sustained spiking activity that might be related to signs of mild colic. Detomidine, and to a lesser extent xylazine, relaxed the whole of the large intestine and this was accompanied by alleviation of the signs of visceral pain.  相似文献   

17.
The sedative effects in horses of the new α2-agonist medetomidine were compared with those of xylazine. Four ponies and one horse were treated on separate occasions with two doses of medetomidine (5 mμ/kg bodyweight and 10 μg/kg bodyweight) and with one dose of xylazine (1 μg/kg bodyweight) given by intravenous injection. Medetomidine at 10 μg/kg was similar to 1 mg/kg xylazine in sedative effect but produced greater and more prolonged ataxia. Ataxia was so severe following 10 μg/kg of medetomidine that one animal fell over during the study. Medetomidine (5 μg/kg) produced less sedation but a similar degree of ataxia to 1 mg/kg xylazine.  相似文献   

18.
Sedative effects of romifidine in the dog   总被引：5，自引：0，他引：5  
The sedative and physiological effects of intravenous romifidine at 0, 20, 40, 80 and 120 μg/kg were investigated in five clinically normal adult male beagle dogs in a blind study using a Latin square design. Following the injection of romifidine, the dogs became ataxic and stood with a wide-based stance, they exhibited signs of skeletal muscle relaxation and their heads were lowered. All the dogs became recumbent and there was a reduction in the heart and respiratory rates. Increasing the dose from 20 to 40 μg/kg, or higher, produced a significant reduction in heart rate. There was an increase in the sedation score following even low doses of romifidine, and although measures of sedation showed no differences among romifidine doses, subjectively, the higher doses produced a more consistent effect. Dogs given lower doses of romifidine regained a standing position more rapidly than following the higher doses, although this effect was not significantly different. A second blind study compared the sedative effects of intravenous romifidine, at 40 and 80 μg/kg, with mede-tomidine at 10 μg/kg in six adult beagles. The cardiopulmonary and sedative effects were not significantly different between all regimens, although medetomidine at 10 μg/kg appeared to be intermediate in effect between romifidine at 40 and 80 μ/kg. The sedative and physiological effects of romifidine in dogs appear to be similar to other α2-adrenoceptor agonists. Intravenous administration provided sedation which might be clinically useful.  相似文献   

19.
REASONS FOR PERFORMING STUDY: Recovery from inhalant anaesthesia in the horse is a critical and difficult period to manage; however, several factors could help to obtain a calm recovery period including choice of anaesthetic and analgesic procedure used and the conditions under which anaesthetic maintenance and recovery occur. OBJECTIVES: The objective of this study was to evaluate and compare the quality of recovery in horses administered saline, xylazine, detomidine or romifidine during recovery from isoflurane anaesthesia. METHODS: Six mature and healthy horses were premedicated with i.v. xylazine and butorphanol, and anaesthesia induced using ketamine. After 2 h of inhalant anaesthesia with isoflurane vaporised in oxygen, saline solution, xylazine (0.1 mg/kg bwt), detomidine (2 microg/kg bwt) or romifidine (8 pg/kg bwt) were administered. The quality of recovery of each horse and the degree of sedation and ataxia were evaluated. Cardiovascular and respiratory parameters were recorded, and arterial blood samples obtained and analysed for pH, PO2 and PCO2 during recovery. RESULTS: Quality of recovery was better in groups treated with alpha-2 adrenergic receptors agonists, showing less ataxia. Degree of sedation was greater in the romifidine group. CONCLUSIONS: We concluded that the administration of alpha-2 adrenoceptor agonists during recovery from isoflurane anaesthesia in horses prolonged and improved the quality of recovery without producing significant cardiorespiratory effects. POTENTIAL CLINICAL RELEVANCE: Administration of alpha-2 adrenoceptor agonists after inhalent anaesthesia could prevent complications during the recovery period.  相似文献   

20.
OBJECTIVE: To evaluate sedative effects of IM administration of a low dose of romifidine in dogs. ANIMALS: 13 healthy adult Beagles. PROCEDURE: Physiologic saline solution (0.2 ml), 0.1 % romifidine (10, 20, or 40 microg/kg), or 10% xylazine (1 mg/kg) was given IM in a crossover study design. Heart rate, respiratory rate, rectal temperature, hemoglobin saturation, and scores for sedation, muscle relaxation, posture, auditory response, and positioning response were recorded before and at regular intervals for up to 240 minutes after drug administration. RESULTS: Scores for sedation, muscle relaxation, posture, auditory response, and positioning response increased in a dose-dependent manner after romifidine administration. Sedation induced by the highest dose of romifidine (40 microg/kg) was comparable to that induced by xylazine (1 mg/kg). Heart rate, respiratory rate, and rectal temperature decreased in a dose-dependent manner after romifidine administration, but hemoglobin saturation did not change. CONCLUSIONS AND CLINICAL IMPLICATIONS: Romifidine (10, 20, or 40 microg/kg, IM) is an effective sedative in dogs, but causes a decrease in heart rate, respiratory rate, and rectal temperature.  相似文献   

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