The aim of this study was to determine whether anesthesia consisting of sedation induced by intramuscular administration of Xylazine-diazepam and lumbosacral analgesia induced by epidural administration of lidocaine and Xylazine is satisfactory for castration and ovariohysterectomy in cats. Six adult (3 male and 3 female, 2.5 ± 0.5 years of age) cats (mean body weight ±  SD, 2.2 ± 0.44 kg) were used in this study. Cats were sedated with Xylazine (1-2 mg kg-1 IM) and diazepam (0.2 mg kg-1, IM) and 5 minutes later a 2% solution of lidocaine (0.5ml/4.5kg) and Xylazine (1 mg kg-1) were administered into the lumbosacral epidural space. Open castration technique or ventral midline routine ovariohysterectomy were performed. Time to onset, duration and cranial spread of analgesia were recorded. Heart rate, respiratory rate and rectal temperature were recorded at time 0 (prior to epidural drugs administration) as a base line values and at 10, 20, 30, 45 and 60 minutes after the epidural administration. Onset time of analgesia was 4.0 ±  0.63 min (Mean ±  SEM) and duration of analgesia was 89.5 ±  3.0 min (Mean ±  SEM). However, surgical procedures were completed within 25-37 min. There were significant decrease in heart rate and rectal temperature values and significant increase in respiratory rate (P < 0.001). Intramuscular administration of Xylazine-diazepam for sedation and epidural administration of lidocaine and Xylazine for analgesia provided satisfactory analgesia for castration and ovariohysterectomy in cats. Utilizing epidural anesthetic technique with this combination is most useful for spaying surgery, especially when the surgical procedure can be completed in < 40 minutes.

Objective- Evaulation of analgesic and sedative characteristics of Xylazine/ketamine combination for caudal epidural analgesia in comparison with two routine agents in donkey. Design- Cross over study.Animals- Five healthy adult donkeys of both sexes with body weights ranging from 150-200 kg. Procedures- Three treatments [lidocaine HCl 2% (0.22 mg kg-1), Xylazine HCl 2% (0.17 mg kg- 1) and Xylazine HCl 2% (0.17 mg kg-1) combined with ketamine HCl 10% (1 mg kg-1)] were evaluated and animals received each of treatments randomly at one-week intervals. Cardiopulmonary parameters and rectal temperature were recorded before and every 15 minutes after epidural administration. The onset and duration of analgesia were evaluated every 5 minutes, using noxious stimulus (pin prick and pinch tests) on the skin of tail, perineum, anus and back thigh. Ataxia was assessed qualitatively between onset of anesthesia and return of sensation. The data were analyzed using analysis of variance followed by Dunnett's test; a Pvalue <0.05 was considered significant.Results- Administration of Xylazine along with ketamine resulted in more rapid onset and longer duration of analgesia (P<0.05), without any measurable cardiopulmonary side effects in comparison with the other treatments. However, severe ataxia was observed after the injection.Conclusion and Clinical Relevance- In a clinical point of view, despite early induction and longer duration of analgesia, this combination at these doses is not suitable for standing surgeries of hindquarters in donkey because there was unacceptable likelihood of recumbency.

Objective: To compare the effects of Xylazine-ketamine and Xylazine-thiopental on cardiac rhythm in dogs.Design: Experimental study. Animals: 15 mixed-bred, adult dogs of either sex.Procedures: Following premedication with Xylazine HCI, either ketamine HCI or sodium thiopental were administered to dogs. Cardiac rhythm was evaluated before as well as 15, 30, 45, and 60 minutes and 3 days after induction of anesthesia.Results: Sinus arrest/block and first degree atrioventricular (A-V) block were the most common arrhythmias observed after ketamine administration. During thiopental-induced anesthesia, ventricular premature beats with bigeminy pattern and sinus bradycardia were also recorded.Conclusion and Clinical Relevance: Concerning the documented effects of the aforementioned drugs on cardiac rhythm, arrhythmias might be induced by the combination of Xylazine with both anesthetic drugs.

Objective: To compare the time of onset, duration of action and the extent of analgesia produced by a lidocaine/Xylazine combination with that produced by lidocaine and Xylazine alone after injection into the caudal extradural space of the Iranian river buffalo.Design: Observer-blind prospective descriptive trial, Latin square design.Animals: Eleven adult (aged over 2 years) female non-gravid healthy Iranian river buffaloes (Bubalus bubalis), weighing from 450 to 650 kg.Procedure: Caudal extradural analgesia was achieved in buffaloes on 3 occasions at 14-day intervals by injection of 2% lidocaine (L; 0.22 mg kg-1), 2% Xylazine (X; 0.05 mg kg-1), and a combination of 2% lidocaine(0.22 mg kg-1) / 2% Xylazine (LX; 0.05 mg kg-1) in a Latin square design. Analgesia was determined by the lack of response to pin-prick and haemostat pressure in the skin of the caudal areas.Results: Onset of analgesia for X was significantly longer (5.5±0.7 minutes) than that for L or LX. Duration of analgesia was significantly longer for LX (172.3±17.7 minutes) than for either drug used alone (lidocaine, 79.5±5.7 minutes; Xylazine, 136.4±11.4 minutes). In X and LX groups, the level of analgesia ascended to thoracic segments; however, in lidocaine-treated buffaloes thighs, flank, and udders remained sensitive. In all buffaloes, Xylazine, administered either alone or with lidocaine, induced mild to moderate ataxia.Conclusions: The LX combination provided a more rapid onset, a longer duration of analgesia, and a more cranial spread of analgesic effect compared with either drug alone. Clinical relevance: The LX combination may offer a fast and long lasting anesthesia/analgesia to perform obstetrical and surgical procedures without the need for reinjection.

Objective: This study was performed to investigate the analgesic effects of lidocaine, Xylazine and lidocaine/Xylazine combination in eye regional anesthesia.Design: Experimental Study.Animals: Twenty adult goats were randomly designed in 4 groups.Procedures: In group L: 10 ml mixture of lidocaine 2% (5 mg/kg bw) and normal saline, In group LX: 10 ml mixture of lidocaine 2% (5 mg/kg bw), Xylazine 2% (0.05 mg/kg bw) and normal saline, In group X: 10 ml mixture of Xylazine 2% (0.05 mg/kg bw) and normal saline and In group C: 10 ml of normal saline were injected into the retrobulbar space of left eyes via four point method. Onset and duration of eyelids analgesia and glob analgesia/akinesia were compared between the groups. The images were studied serially and compared anatomically with two dissected head and intact goat skulls.Results: The results of this study demonstrated that eye regional anesthesia have not been observed in group C. In group X, sedative effect of Xylazine without complete loss of eyelids and glob anaesthesia was observed. There was no significant difference in onset of eyelids and glob anaesthesia between groups L and LX (p>0.05). Duration of eye regional anesthesia in group LX was significantly more than group L (p<0.05). The animals in groups X and LX were sedated during the study but in group L the animals were alert and nervous.Conclusion and Clinical Relevance: According to results of present study, addition of Xylazine to lidocaine for retrobulbar block causes a sedative effect and increased duration of eye regional anesthesia.

Background & Aim: The major application of tramadol is for the control of chronic pain and management of postoperative pain in humans. The purpose of this study was to evaluate the influence of premedication with tramadol on Xylazine-ketamine anesthesia in animal models.Methods: In this experimental study which was conducted at The Veterinary Medicine School, Islamic Azad University, Karaj Branch, in 2011, 10 dogs from mixed breeds from both sexes, with the mean weight of 20±2 kg were selected and randomly assigned into two groups. In the first group, atropine (0.04 mg/kg), Xylazine (0.55 mg/kg) and ketamine (10 mg/kg) were administered by intramuscular (IM) injection, 5 minutes after either tramadol (2 mg/kg, IV) while in the other group an equal volume of normal saline (IV) used instead of tramadol. Analgesic period and recovery times and physiological parameters were measured and recorded. Data analysis was conducted by using independent sample t-test.Results: Duration of analgesia was 17.2 minutes in tramadol group and 36.4 minutes in saline group. This difference was statistically significant (P=0.02).Conclusion: Based on the findings of this study, addition of tramadol to Xylazine/ketamine reduces the duration of analgesia.

This study aimed to compare the effects of Xylazine or propofol before intrathecal (IT) bupivacaine administration in dogs. The study was conducted in two groups of 10 dogs each. In group I (XG), intrathecal injection of 20 mg bupivacaine was administered into the subarachnoid space in the lumbosacral area after treatment with 1 mg/kg intravenous (iv) Xylazine. In group II (PG), 4 mg/kg iv propofol was administered before IT bupivacaine administration. The onset, duration, and magnitude of sensory block (scale 0– 3) were determined using the pin-prick test throughout the anesthesia. Duration of surgery (XG: 47. 20 ± 5. 01 min, PG: 50. 85 ± 6. 97 min) and duration of anesthesia (XG: 92. 20 ± 7. 02 min, PG: 94. 50 ± 7. 26 min) were not significantly different between the groups. This study concludes that propofol administration before IT anesthesia with bupivacaine maintains safe levels of IT anesthesia and can therefore be used as an alternative to Xylazine treatment.

The effects of Xylazine hydrochloride and ketamine hydrochloride as potential anesthetic compounds were examined intravenously on two species of sturgeon: Acipenser stellatus and Acipenser persicus. The induced stress was determined by tracing plasma glucose and cortical as stress indicators. It was found that injection of 10 mg ketamine per kilogram of fish weight causes anesthesia in two minutes which lasts for 30-60 minutes. Also injection of 10 and 11mg Xylazine per kilogram of fish weight causes anesthesia in three minutes which lasts for 40-120 minutes. Analysis of data of tracing glucose and cortisol indicated these two compounds as stressive.

The objective of this study was to evaluate the analgesic, sedative and cardiopuhnonary effects of epidurally administered ketamine and Xylazine combination in the horse. Ten healthy horses (3 stallions and 7 mares) weighing 300 - 350 kg and aged between 6 - 12 years selected and the skin of sacrococcygeal region prepared for needle placement. Ketamine with the dose Xylazine with the dose of 0.5 mg / kg prepared in a syringe and injected in caudal epidural region (C1- C2). The onset, duration and extent of analgesia evaluated after injection. Heart and respiratory rates and also rectal temperature were recorded on 0, 5, 15, 30, 60 minutes after injection. This combination caused excellent analgesia of the tail, perinea region, anus and vulva within 9±2.3 minutes and lasted for more than 120 minutes observation period. Evaluation of analgesia was carried out by pin prick test. Heart rate decreased significantly from baseline after 15 minutes. Respiratory rate also reduced significantly after 30 minutes in comparison to baseline. Rectal temperature did not change significantly. In conclusion the results of this study indicate that caudal epidural administration of the combination of ketamine and Xylazine with the above mentioned doses could produce good analgesia of the caudal region with minimal cardio - respiratory effects.

The possibility of using ketamine hydrochloride and combination of ketamine and Xylazine hydrochloride were studied in common carp. The study was carried out on about 300 carps weighting 10-30 grams, in 24-26c water temperature, ketamine dissoved in water at different concentration (15: 200 mg/l). Ec50 and Lc50 in 15 min. for this drug were 35 and 170 mg/l respectively. For using ketamine and Xylazine in combination, the fishes were placed in a solution of 15 mg/I Xylazine for 15 minutes as a pre anaesthetic agent, then in different concentrations of ketamine (20-250 mg/l), in 1 min. In this situation, Ec50 and Lc50 for ketamine were 36.3 and 230 mg/l respectively as the result ketamine and combination of ketamine and Xylazine could be used as an immobilization and anaesthetic agent in common carp but for their commercial use research need to do further research.