Reversible chemical restraint of free-range cattle with a concentrated combination of tiletamine-zolazepam, ketamine, and detomidine.

The aim of this study was to determine the efficacy of a concentrated combination of tiletamine-zolazepam [TZ, 0.53 mg/kg body weight (BW)], ketamine (Ket, 0.53 mg/kg BW), and detomidine (Det, 0.04 mg/kg BW) in the immobilization of free-range cattle for clinical procedures. The combination was administered intramuscularly to 53 animals. Anesthesia was reversed with the α2-adrenoceptor antagonist atipamezole. Locoregional anesthesia was provided with lidocaine when required. The TZKD combination induced suitable immobilization for minor surgical procedures or medical treatments. Anesthetic onset was rapid, taking a mean of 6.1 min [standard deviation (SD) 2.8 min]. The duration of anesthesia depended on the time of administration of the antagonist; the animals recovered in the standing position in 12.9 ± 8.9 min after the administration of atipamezole. The quality of anesthesia and analgesia were satisfactory. In conclusion, this TZKD combination can be used for both immobilization and minor surgical procedures in free-range cattle.

L'objectif de la présente étude était de déterminer l'efficacité d'une combinaison concentrée de tiletamine-zolazepan [TZ, 0,53 mg/kg de poids corporel (BW)], kétamine (Ket, 0,53 mg/kg de BW), et detomidine (Det, 0,04 mg/kg BW) pour l'immobilisation de bovins libres au pâturage aux fins de procédures cliniques. La combinaison fut administrée à 53 animaux par voie intramusculaire. L'anesthésie a été renversée avec l'atipamézole, antagoniste des adrénocepteurs-α2. Au besoin, l'anesthésie locorégionale a été induite avec de la lidocaïne. La combinaison TZKD a induit une immobilisation adéquate pour des procédures chirurgicales mineures ou des traitements médicaux. L'initiation de l'anesthésie était rapide, avec une moyenne de 6,1 minutes [écart-type (SD) 2,8 min]. La durée de l'anesthésie dépendait du temps de l'administration de l'antagoniste; les animaux récupérant en position debout en 12,9 ± 8,9 min après l'administration de l'atipamézole. La qualité de l'anesthésie et de l'analgésie était satisfaisante. En conclusion, la combinaison TZKD peut être utilisée pour l'immobilisation et la réalisation de procédures chirurgicales mineures chez les bovins au pâturage.(Traduit par Docteur Serge Messier).

Antagonistic effect of atipamezole, flumazenil and naloxone following anaesthesia with xylazine, tramadol and tiletamine/zolazepam combinations in pigs.

OBJECTIVE: To evaluate the antagonistic effects of atipamezole (ATI), flumazenil (FLU) and naloxone (NAL) alone and in various combinations following administration of tiletamine-zolazepam-xylazine-tramadol. STUDY DESIGN: Prospective, experimental, randomized cross-over study. ANIMALS: Eight Chinese miniature pigs (three females and five males) mean age 8 (range 7-10) months and bodyweight 57.5 (52.4-62.1) kg. METHODS: All animals were anaesthetized with tiletamine/zolazepam (3.0 mg kg(-1)), xylazine (1.2 mg kg(-1)) and tramadol (1.6 mg kg(-1)) given intramuscularly (IM). Thirty minutes later, one of eight treatments was administered IM: saline control, ATI (0.12 mg kg(-1)), FLU (0.1 mg kg(-1)), NAL (0.03 mg kg(-1)), ATI-FLU, FLU-NAL, ATI-NAL or ATI-FLU-NAL. After injection of antagonists the following times were recorded: to recovery of the palpebral, pedal and tail clamp reflexes, to head movement, sternal recumbency, standing and walking. Posture, sedation, analgesia, jaw relaxation and auditory response were scored at set times until 120 minutes after injection of antagonists. Heart rates, respiratory rates and rectal temperature were measured at those times. Data were analyzed by anova for repeated measures, followed by the Tukey's test to compare differences between means, or by Kruskal-Wallis test as appropriate. RESULTS: FLU, NAL alone, or FLU-NAL did not effectively antagonize anaesthesia induced by tiletamine/zolazepam-xylazine-tramadol. ATI, ATI-FLU, ATI-NAL and ATI-FLU-NAL produced an immediate and effective recovery from anaesthesia. The combination of ATI-FLU-NAL was the most effective combination in antagonizing the anaesthetic effect. Adverse effects such as tachycardia, tachypnoea, excitement and muscle tremors were not observed during this study. CONCLUSION AND CLINICAL RELEVANCE: ATI-FLU-NAL is the most effective combination for antagonizing tiletamine/zolazepam-xylazine-tramadol anaesthesia in pigs. However, ATI alone or in various combinations also provides effective antagonism.

Effectiveness of antagonists for tiletamine-zolazepam/xylazine immobilization in female white-tailed deer.

A combination of tiletamine-zolazepam/xylazine (TZ/X) is effective in the chemical immobilization of white-tailed deer (Odocoileus virginianus); however, the lengthy duration of immobilization may limit its usefulness. From October to November 2002, 21 captive female deer were assigned randomly to an alpha(2) antagonist treatment to reverse xylazine-induced sedation (seven does per group). All deer were given 220 mg of TZ (4.5+/-0.4 mg/kg) and 110 mg of X (2.2+/-0.2 mg/kg) intramuscularly (IM). Antagonist treatments were either 200 mg of tolazoline (4.0+/-0.4 mg/kg), 11 mg of atipamezole (0.23+/-0.02 mg/kg), or 15 mg of yohimbine (0.30+/-0.02 mg/kg) injected, half intravenously and half subcutaneously, 45 min after the IM TZ/X injection. In addition, 10 other deer (five per group) were immobilized as before and then given tolazoline (200 mg) after 45 min, with either a carrier (dimethyl sulfoxide [DMSO]) or carrier (DMSO) plus flumazenil (5 mg) to reverse the zolazepam portion of TZ. Mean times from antagonist injection until a deer raised its head were different for alpha(2) antagonist treatments (P=0.02). Times were longer for yohimbine (62.3+/-42.7 min) than for either atipamezole (24.3+/-17.1 min) or tolazoline (21.3+/-14.3 min). Mean times from antagonist injection until standing were not different (P=0.15) among yohimbine (112.0+/-56.4 min), atipamezole (89.7+/-62.8 min), or tolazoline (52.6+/-37.2 min). A sedation score based on behavioral criteria was assigned to each deer every 30 min for 5 hr. On the basis of sedation scores, tolazoline resulted in a faster and more complete reversal of immobilization. Flumazenil treatment did not affect recovery.

A comparison of carfentanil/xylazine and Telazol/xylazine for immobilization of white-tailed deer.

October 2001 to January 2002, captive free-ranging white-tailed deer (Odocoileus virginianus) were immobilized with a combination of carfentanil citrate and xylazine hydrochloride. From this study, we selected a dose of carfentanil/xylazine for the purpose of comparing immobilization parameters and physiologic effects with those of a combination of tiletamine and zolazepam (Telazol) and xylazine. Animals were initially given intramuscular injections of 10 mg xylazine and one of four doses of carfentanil (i.e., 0.5, 1.0, 1.5, and 2.0 mg). A carfentanil dose of 1.2 mg (x +/- SD = 23.5 +/- 3.2 microg/kg) and 10 mg xylazine (0.2 +/- 0.03 mg/kg) were selected, based on induction times and previously published reports, to compare with a combination of 230 mg of Telazol (4.5 +/- 0.6 mg/kg) and 120 mg xylazine (2.3 +/- 0.3 mg/kg). Time to first observable drug effects and to induction were significantly longer for deer treated with carfentanil/xylazine than with Telazol/xylazine (P < 0.01). Hyperthermia was common in deer immobilized with carfentanil/xylazine, but heart rate, respiration rate, and hemoglobin saturation were within acceptable levels. Degree of anesthesia of deer immobilized with Telazol/xylazine was superior to deer immobilized with carfentanil/xylazine. The combination of 120 mg of naltrexone hydrochloride and 6.5 mg of yohimbine hydrochloride provided rapid and complete reversal (1.9 +/- 1.1 min) of carfentanil/xylazine immobilization. Animals immobilized with Telazol/xylazine had long recovery times with occasional resedation after antagonism with 6.5 mg of yohimbine. The combination of carfentanil and xylazine at the doses tested did not provide reliable induction or immobilization of white-tailel (leer even though drug reversal was rapid and safe using naltrexone and yohimbine.

Partial antagonism of tiletamine-zolazepam anesthesia in cheetah.

This study evaluated partial antagonism of tiletamine-zolazepam (TZ) anesthesia in cheetahs (Acinonyx jubatus) and differences between two benzodiazepine antagonists, flumazenil and sarmazenil, in this species. Four cheetahs were anesthetized three times at an interval of 14 days with an average intramuscular dose of 4.2 mg/kg TZ. In trials 2 and 3 flumazenil at 0.031 mg/kg and sarmazenil at 0.1 mg/kg, respectively, were applied intramuscularly 30 min after initial TZ injection. There was a highly significant difference between the duration of TZ anesthesia with and without antagonist. Use of the antagonists significantly shortened duration and recovery and eliminated excitatory behavior during the recovery phase. No significant differences could be determined between the two antagonists. We recommend the use of sarmazenil and flumazenil to antagonize TZ anesthesia in cheetahs.

Tiletamine-zolazepam, ketamine, and xylazine anesthesia of captive cheetah (Acinonyx jubatus).

Thirty-two anesthetic episodes used a combination of tiletamine-zolezepam (50 mg/ml each), ketamine (80 mg/ml), and xylazine (20 mg/ml) at various dosages for routine diagnostic and minor surgical procedures in 13 captive cheetahs (Acinonyx jubatus). The mean dosage (0.023 +/- 0.003 ml/kg) provided rapid induction with a single i.m. injection along with safe predictable working time, good muscle relaxation, and analgesia. Yohimbine administration subsequently accelerated smooth and rapid recovery.

Use of medetomidine-zolazepam-tiletamine with and without atipamezole reversal to immobilize captive California sea lions.

From June 1998 to August 1999, 39 California sea lions (Zalophus californianus) were immobilized at a rehabilitation center in northern California (USA) using medetomidine plus zolazepam and tiletamine (MZT), alone and in combination with isoflurane, with atipamezole reversal. Animals were given 70 microg/kg medetomidine with 1 mg/kg of a 1:1 solution of tiletamine and zolazepam intramuscularly. Mean (+/-SD) time to maximal effect was 5+/-3 min. At the end of the procedure, animals were given 200 microg/kg atipamezole intramuscularly. Immobilization and recovery times were, respectively, 28+/-18 and 9+/-7 min for 15 animals maintained with MZT alone and 56+/-47 and 9+/-6 min for 18 animals intubated and maintained with isoflurane. One mortality occurred during anesthesia. Other disadvantages of the MZT combination included some prolonged ataxia, weakness and disorientation during recovery. However, the use of MZT resulted in faster induction and a more reliable plane of anesthesia that was reversible with atipamezole and safer than other previously used intramuscular agents. Physiological parameters including heart rate, respiratory rate, temperature, pulse oximeter saturation, and end-tidal carbon dioxide were monitored.

Immobilization of babirusa (Babyrousa babyrussa) with xylazine and tiletamine/zolazepam and reversal with yohimbine and flumazenil.

Twelve babirusa (Babyrousa babyrussa) (four females/eight males) were immobilized 30 times during a 4-yr interval. Significantly higher premedication and immobilizing doses were needed for females than for males (P < 0.05). An i.m. preanesthetic xylazine dose of 1.88 +/- 0.37 mg/kg (range = 1.20-2.12 mg/kg) was used for females and 1.22 +/- 0.16 mg/kg (range = 0.82-1.43 mg/kg) for males. After xylazine, the animals were induced with i.m. tiletamine/zolazepam; females received 2.20 +/- 0.47 mg/kg (range = 1.78-3.33 mg/kg) and males received 1.71 +/- 0.34 mg/kg (range = 1.08-2.05 mg/kg). Anesthesia was reversed with yohimbine (0.14 +/- 0.03 mg/kg; range = 0.07-0.20 mg/kg) and flumazenil (1 mg flumazenil/20 mg zolazepam) either i.m. or i.v. This anesthetic combination produced smooth induction, good relaxation, and sufficient immobilization to perform routine diagnostic and therapeutic procedures (venipuncture, hoof and tusk trims, transportation, radiographs, ultrasound examination, weight determinations, and skin biopsies). Supplemental ketamine HCl or isoflurane was administered to two animals to effectively deepen or prolong the anesthetic plane, with no resultant adverse effects.

Health evaluation of free-ranging guanaco (Lama guanicoe).

Twenty free-ranging guanaco (Lama guanicoe) in Chubut Province, Argentina, were immobilized for health evaluations. All but two animals appeared to be in good condition. Hematology, serum chemistry, and vitamin and mineral levels were measured, and feces were evaluated for parasites. Serology tests included bluetongue, brucellosis, bovine respiratory syncitial virus, bovine viral diarrhea/mucosal disease, equine herpesvirus 1, infectious bovine rhinotracheitis, Johne's disease (Mycobacterium paratuberculosis), foot and mouth disease, leptospirosis (17 serovars), parainfluenza-3, and vesicular stomatitis. Blood samples from 20 domestic sheep (Ovis aries) maintained in the same reserve with the guanaco were also collected at the same time for serology tests. No guanaco had positive serologic tests. Sheep were found to have antibody titers to bovine respiratory syncytial virus, Johne's disease, leptospirosis, and parainfluenza-3. There was no apparent difference in external appearance or condition, or statistical difference in blood test values, between the animals that were positive or negative for parasite ova.

Tiletamine-zolazepam anesthesia in North American river otters (Lutra canadensis) and its partial antagonism with flumazenil.

North American river otters (Lutra canadensis) were anesthetized with tiletamine-zolazepam or tiletamine-zolazepam-flumazenil combinations in cooperation with the North Carolina Wildlife Resources Commission Otter Restoration Project for evaluation of physiologic changes during anesthesia. Sixteen otters received tiletamine-zolazepam (4 mg/kg combined, i.m.) in 1994. Induction and recovery times were recorded and physiologic data (heart rate and rhythm, respiratory rate, rectal temperature, relative oxyhemoglobin saturation, and mean arterial blood pressure) were collected at 5-min intervals. Respiratory depression developed initially in all otters, and median relative oxyhemoglobin saturation remained below 90% for the first 15 min of anesthesia. Anesthetic induction with tiletamine-zolazepam was rapid and smooth, but recovery was prolonged (median = 89 min) and characterized by persistent head motion. In 1995, flumazenil was evaluated as a partial antagonist for tiletamine-zolazepam anesthesia in otters. Sixteen otters were anesthetized with tiletamine-zolazepam (4 mg/kg combined, i.m.) and given flumazenil (1 mg per 25 mg of zolazepam) after 20 min. Flumazenil markedly shortened recovery time in all otters anesthetized with tiletamine-zolazepam (median = 65 min) with no adverse effects.

Antagonism of some cyclohexamine-based drug combinations used for chemical restraint of southern elephant seals (Mirounga leonina).

This study examined the use of 4 antagonists of chemical restraint in mature female southern elephant seals (Mirounga leonina) that were restrained with ketamine and diazepam, ketamine and xylazine, or tiletamine and zolazepam. The antagonists were: 4-aminopyridine, yohimbine, doxapram and sarmazenil. The effects of the antagonists on the animal's time to first movement forward and recovery, heart rate, respiratory rate and venous blood gas and pH values, and level of chemical restraint were recorded. Sarmazenil (1.0 mg/kg) and doxapram (5.0 mg/kg) partially antagonised 50:1 ketamine: diazepam (ketamine = 3.0 mg/kg, diazepam = 0.06 mg/kg) and tiletamine and zolazepam (tiletamine = 0.5 mg/kg, zolazepam = 0.5 mg/kg). However, the rapid recovery after low doses of anaesthetics means that antagonism is usually unnecessary, and it may increase the likelihood of shaking. Routine antagonism of ketamine and xylazine (ketamine = 3.0 mg/kg, xylazine = 0.5 mg/kg) is more useful given its usually delayed recovery time and potential for thermoregulatory problems. For this purpose yohimbine (0.06 mg/kg) offered advantages over doxapram in giving a smoother recovery with less aggression. 4-aminopyridine (0.2 mg/kg) prolonged chemical restraint by 100:1 ketamine:diazepam (ketamine = 3.0 mg/kg, diazepam = 0.03 mg/kg) and ketamine and xylazine, and should be contraindicated. Doxapram (5.0 mg/kg) was the most useful general antagonist for all groups of drugs but shaking was seen and a lower dose is recommended.

Immobilization of Rocky Mountain elk with Telazol and xylazine hydrochloride, and antagonism by yohimbine hydrochloride.

Ten trapped Rocky Mountain elk (Cervus elaphus nelsoni) were successfully immobilized with a combination of 500 mg Telazol and 60 mg xylazine hydrochloride (HCl) from 9 July to 25 August 1993 in Custer State Park, South Dakota (USA). Mean (SD) dosages of 2.5 (0.6) mg/kg Telazol and 0.3 (0.1) mg/kg xylazine HCl, respectively, were administered, resulting in a mean (SD) induction time of 4.6 (0.8) min. Induction time varied with weight and dosage. Respiratory rate (breaths/min) increased following injection of Telazol and xylazine HCl and remained elevated or continued to increase through 10 min post-injection and then declined. There were no mortalities in this study. Forty mg of yohimbine HCl was used as an antagonist in eight elk, resulting in a mean (SD) recovery time of 14.0 (9.9) min when administered intravenously (n = 6), and 124.7 (9.5) min when given intramuscularly (n = 2). Recovery time varied with weight and dosage of yohimbine. Elk given 2.1 to 2.6 mg/kg Telazol and 0.1 to 0.3 mg/kg xylazine HCl responded to yohimbine HCl when administered intravenously.

[Anesthesia in dogs with the combination preparation Tilest 500]. / Anästhesie beim Hund mit dem Kombinationspräparat Tilest 500.

Tilest 500 contains tiletamine and the water-soluble benzodiazepine zolazepam in the ratio 1:1. The drug was administered intramuscularly in ten dogs at a dosage of 10 mg/kg bwt of tiletamine and 10 mg/kg bwt of zolazepam and tested for its effects on hemodynamics, respiration, and the antagonistic effect of flumazenil. Initial effects occurred quickly, analgesia and muscle relaxation were excellent 10 minutes after administration. There was a highly significant increase in heart rate and a slight decrease in both mean arterial blood pressure and arterial pO2. In a second group of ten dogs the interventricular paraconal branch of the left coronary artery was ligated which induced local myocardial ischemia. Here Tilest 500 showed electrostabilizing and antifibrillatory properties even in the presence of severe arrhythmias. The benzodiazepine compound of this drug combination can be antagonized by flumazenil. To avoid excitatory reactions flumazenil should not be injected earlier than 45 to 60 minutes after administration of Tilest 500.