Administration Of Alfaxalone Research Articles

Impact of procedural handling on the physiological effects of alfaxalone anaesthesia in the ball python (Python regius)

To describe the cardiovascular changes following intramuscular (handled) and intravascular (undisturbed, via intraarterial catheter) alfaxalone administration, we studied 20 healthy ball pythons (Python regius) in a randomised, prospective study. The pythons were instrumented with occlusive arterial catheters to facilitate undisturbed, continuous monitoring of heart rate and blood pressure. Six pythons were administered intramuscular (IM) saline, followed by 20 mg/kg IM alfaxalone, and were manually restrained for both injections. Six pythons received intraarterial (IA) saline, followed by 10 mg/kg IA alfaxalone, and remained undisturbed for both injections. Arterial blood samples were taken at 0, 12 and 60 min post-injection, and heart rate and blood pressure were recorded for 60 min. The remaining eight snakes received 20 mg/kg IM or 10 mg/kg IA alfaxalone (n = 4 per treatment) and were not handled for intubation 10 min post-injection, to examine the effects of handling during anaesthesia. IM administration of 20 mg/kg alfaxalone or an equivalent volume of saline elicited a profound tachycardia and hypertension, which recovered to resting values after 20 min. However, when 10 mg/kg alfaxalone or saline were injected IA, mild hypotension and a lower magnitude tachycardia occurred. Arterial PCO2 and PO2, pH and lactate concentrations did not change following IA alfaxalone, but an acidosis was observed during IM alfaxalone anaesthesia. There were no significant changes in plasma catecholamines and corticosterone among treatments. Handling for injection and during anaesthesia associated with intubation significantly affects cardiovascular parameters, whereas alfaxalone per se only elicits minor changes in cardiovascular physiology.

Effects of intramuscular alfaxalone and dexmedetomidine alone and combined on ocular, electroretinographic, and cardiorespiratory parameters in normal cats.

This study aimed to determine the effects of intramuscular (IM) administration of alfaxalone with or without dexmedetomidine on short electroretinography (ERG), ocular parameters and cardiorespiratory in healthy cats. Eight healthy female spayed cats were treated with three sedation protocols: IM administration of 5 μg/kg dexmedetomidine (DEX), 5 mg/kg alfaxalone (ALF), and 5 μg/kg dexmedetomidine plus 5 mg/kg alfaxalone (DEX + ALF). The washout period after each treatment was 2 weeks. Physiological parameters, time metrics, intraocular pressure (IOP), Schirmer tear test 1 (STT-1) and a short ERG protocol were recorded. For age data, weight data, time metrics and ERG data, one-way ANOVA with Bonferroni posterior comparisons were performed. For physiological parameters, IOP and STT-1 data, two-way repeated measures ANOVA with Bonferroni posterior comparisons were performed. Statistical significance was set at a p-value <0.05. IOPs were increased in all three groups compared to baseline and showed no significant differences among three groups at any time point. STT-1 values were decreased significantly during the process. Significant differences were noticed between a-wave amplitude in the dark-adapted response between DEX and ALF, and a-wave amplitude in light-adapted response between ALF and DEX + ALF. This study demonstrates the feasibility of three sedation protocols for short ERG recording in cats. All these treatments resulted in increased IOP values and reduced STT-1 values. But baseline data of ERG was not obtained as a blank control in cats.

COMPARISON OF THREE MIDAZOLAM-BASED SEDATION PROTOCOLS IN BUDGERIGARS (MELOPSITTACUS UNDULATUS) AND BLACK-CHEEKED LOVEBIRDS (AGAPORNIS NIGRIGENIS).

This randomized, crossover study evaluated three sedation protocols administered subcutaneously in nine budgerigars (Melopsittacus undulatus) and nine black-cheeked lovebirds (Agapornis nigrigenis). All protocols included midazolam (5 mg/kg), combined with butorphanol (5 mg/kg) (BM), medetomidine (20 lg/kg) (MM), or alfaxalone (13 mg/kg) (AM). Mortalities from suspected cardiorespiratory arrest were observed when AM was used in lovebirds, even after reduction of alfaxalone dosage to 3 mg/kg, and therefore this protocol was excluded from further use in this species. Induction and recovery times were recorded and their quality assessed. Sedation depth and heart and respiratory rates were measured every 5 min and radiographic positioning was attempted at 10 and 20 min. At 30 min, midazolam and medetomidine were reversed with flumazenil (0.05 mg/kg, SC), and atipamezole (0.2 mg/kg, SC), respectively. MM consistently provided deep sedation in both species, with successful radiographic positioning at every attempt. As expected, heart rate was often lower with MM than with other protocols, but no associated complications were noted. In budgerigars, BM had the lowest radiographic positioning success rate (10 min: 5/9, 20 min: 3/9), whereas in lovebirds it provided significantly deeper sedation (P < 0.001), allowing radiographic positioning in all subjects. In both species, BM provided the shortest recovery times. AM resulted in reliable radiographic positioning of all budgerigars at 10 min, but not at 20 min (5/ 9), and provided consistently poor recoveries. This study highlights how differently two psittacine species of similar size may react to the same sedation protocols. AM sedation cannot be fully reversed and produced significant undesirable effects, several of which have been previously reported with alfaxalone administration to avian species. The authors therefore caution against using alfaxalone-midazolam combinations in budgerigars and black-cheeked lovebirds. Both BM and MM provided reliable sedation in these species, and appear to be suitable alternatives to AM.

Sedation Quality and Cardiorespiratory, Echocardiographic, Radiographic and Electrocardiographic Effects of Intramuscular Alfaxalone and Butorphanol in Spanish Greyhound Dogs.

The quality of sedation and changes in cardiorespiratory variables after the intramuscular administration of alfaxalone and butorphanol in Spanish greyhound dogs were evaluated. Twenty-one adult dogs were included. The dogs received alfaxalone (2 mg/kg) and butorphanol (0.2 mg/kg) intramuscularly. Sedation scoring, cardiorespiratory parameters (including blood gas analysis), echocardiography, thoracic radiography and electrocardiography were performed before sedation and 30 min after drug administration. Moderate sedation was observed, and side effects, such as tremors, nystagmus and auditory hyperesthesia, were noticed. Statistically significant changes in heart rate, invasive blood pressure, pH, arterial saturation of O2 and partial pressure of O2 and CO2 were found. Echocardiographic variables, including end-diastolic volume, left ventricular diameter in diastole, aortic and pulmonic flow, diastolic transmitral flow and left atrial/aortic ratio, and electrocardiography parameters, including PQ interval and QT interval, showed statistically significant changes. In conclusion, the intramuscular administration of alfaxalone and butorphanol to healthy dogs produced moderate sedation with mild cardiorespiratory, echocardiographic and electrocardiographic changes, without alterations in cardiac size on radiographic images.

Anaesthetic induction with alfaxalone in Jungle Carpet Python (Morelia Spilota Cheynei)

The aim of this investigation was to assess the clinical use of alfaxalone as a short-acting anaesthetic agent for induction to inhalation anaesthesia in jungle carpet pythons (Morelia spilota cheynei). Ten healthy, captive, sub-adult jungle carpet pythons (1.1±0.32 kg bw) were anaesthetised using a dose of 10mg/kg of alfaxalone, administered intravenously to the ventral tail vein. Heart rate (HR) and respiratory rate (RR) were recorded before administration (T0), and every 5 minutes until the snakes fully recovered from the anaesthesia. The induction time, time of tail-pinch reflex loss, tracheal tube insertion time, interval of deep anaesthesia, and the time of full recovery were recorded. The induction time occurred within 3.1±0.8 minutes. The tail-pinch reflex loss was lost within 5.6±0.7 minutes. The mean tracheal tube insertion time, the interval of deep anaesthesia, and the time of full recovery were 6.9±0.9 minutes, 18.8±4.7 minutes, and 36.7±11.4 minutes, respectively. A prolonged time of full recovery was recorded in two snakes (61.3 and 62.6 minutes, respectively). Their mean heart rate was statistically higher (P&lt;0.05) at T5, T15 and T20 when compared with the basal HR at T0. The respiratory rate of the snakes dropped at T5 and was statistically lower (P&lt;0.05) from T5 until T20 when compared with RR at all other time points. In two snakes apnoea was recorded at T5. Intravenous administration of alfaxalone proved to be a valuable method of induction, suitable for a subsequent inhalation anaesthesia in jungle carpet pythons.

Prophylactic use of a lidocaine constant rate infusion versus saline in dogs undergoing balloon valvuloplasty for management of pulmonic stenosis: A randomized control trial

ObjectiveTo evaluate the effect of a prophylactic lidocaine constant rate infusion (CRI) on the incidence and malignancy of catheter-induced ventricular ectopic complexes (VECs) during balloon valvuloplasty for management of pulmonic stenosis in dogs. Study designSingle-centre, prospective, randomized study. AnimalsClient-owned dogs (n = 70) with pulmonic stenosis. MethodsDogs were randomly assigned to one of two anaesthetic protocols: administration of lidocaine 2 mg kg–1 bolus followed by a CRI (50 μg kg–1 minute–1; group LD) or a saline placebo (group SL) during balloon valvuloplasty. All dogs were premedicated with methadone (0.3 mg kg–1) intramuscularly and a digital three-lead Holter monitor was applied. Anaesthetic co-induction was performed with administration of alfaxalone (2 mg kg–1) and diazepam (0.4 mg kg–1), and anaesthesia was maintained with isoflurane vaporised in 100% oxygen. CRIs were started on positioning of the dog in theatre and discontinued as the last vascular catheter was removed from the heart. All dogs recovered well and were discharged 24 hours postoperatively. Blinded Holter analysis was performed by an external veterinary cardiologist using commercially available dedicated analysis software; p < 0.05. ResultsOf the 70 dogs enrolled in the study, 61 were included in the final analysis: 31 in group LD and 30 in group SL.There was no significant difference between sinus beats (p = 0.227) or VECs (p = 0.519) between groups. In group LD, 19/31 (61.3%) dogs had a maximum ventricular rate ≥250 units and 20/30 (66.7%) dogs in group SL (p = 0.791). Conclusion and clinical relevanceIn this study, the use of a prophylactic lidocaine bolus followed by CRI in dogs undergoing balloon valvuloplasty for management of pulmonic stenosis did not significantly decrease the incidence nor the malignancy of VECs during right heart catheterization compared with a saline CRI.

Effect of intravenous fentanyl on cough reflex and quality of endotracheal intubation in cats

ObjectiveTo assess the effects of intravenous (IV) fentanyl on cough reflex and quality of endotracheal intubation (ETI) in cats. Study designRandomized, blinded, negative controlled clinical trial. AnimalsA total of 30 client-owned cats undergoing general anaesthesia for diagnostic or surgical procedures. MethodsCats were sedated with dexmedetomidine (2 μg kg–1 IV), and 5 minutes later either fentanyl (3 μg kg–1, group F) or saline (group C) was administered IV. After alfaxalone (1.5 mg kg–1 IV) administration and 2% lidocaine application to the larynx, ETI was attempted. If unsuccessful, alfaxalone (1 mg kg–1 IV) was administered and ETI re-attempted. This process was repeated until successful ETI. Sedation scores, total number of ETI attempts, cough reflex, laryngeal response and quality of ETI were scored. Postinduction apnoea was recorded. Heart rate (HR) was continuously recorded and oscillometric arterial blood pressure (ABP) was measured every minute. Changes (Δ) in HR and ABP between pre-intubation and intubation were calculated. Groups were compared using univariate analysis. Statistical significance was set as p < 0.05. ResultsThe median and 95% confidence interval of alfaxalone dose was 1.5 (1.5–1.5) and 2.5 (1.5–2.5) mg kg–1 in groups F and C, respectively (p = 0.001). The cough reflex was 2.10 (1.10–4.41) times more likely to occur in group C. The overall quality of ETI was superior in group F (p = 0.001), with lower laryngeal response to ETI (p < 0.0001) and ETI attempts (p = 0.045). No differences in HR, ABP and postinduction apnoea were found. Conclusions and clinical relevanceIn cats sedated with dexmedetomidine, fentanyl could be considered to reduce the alfaxalone induction dose, cough reflex and laryngeal response to ETI and to improve the overall quality of ETI.

Effects of alfaxalone on induction quality of inhalation anesthesia in domestic pigeons (Columba livia domestica).

Several studies have documented the effects of anesthesia on pigeons. However, previous studies using pigeons have not examined a combination of injection and inhalation anesthesia. This study aimed to evaluate the effects of intramuscular (IM) administration of alfaxalone in conjunction with mask induction on the quality of isoflurane anesthesia in healthy domestic pigeons (Columba livia domestica). In a randomized, double-blind, crossover study consisting of two phases, six healthy adult pigeons were anesthetized twice with a washout period of 7 days. In each phase, the pigeons were randomly assigned IM administration of either alfaxalone (4 mg/kg) or an equal volume of normal saline. After 20 min, anesthesia was induced with isoflurane through a face mask. Once voluntary movement of the limbs and eyelids ceased, the face mask was removed, and the trachea was intubated. The quality of anesthesia was assessed by scoring sedation prior to anesthetic induction, induction, and recovery. Heart rate, respiratory rate, cloacal temperature, and noninvasive systolic, diastolic, and mean arterial pressure were recorded before the IM injection (baseline) and during the procedure. The minimum anesthetic concentration of isoflurane was determined using the "bracketing" method. Moderate sedation (sedation scores of 2 and 3) was observed only with alfaxalone administration. In the alfaxalone group, the induction score was significantly higher (better induction quality) than in the control group (P=0.041). The combination of alfaxalone and mask induction was effective for inhalation anesthesia in pigeons.

Comparison of alfaxalone and propofol on haematological and serum biochemical variables in cats undergoing radiotherapy with sevoflurane maintenance

ObjectiveTo evaluate effects of repeated alfaxalone or propofol administration on haematological and serum biochemical variables in cats undergoing radiotherapy. Study designProspective, block-randomized, clinical trial. AnimalsA group of 39 client-owned cats. MethodsAfter butorphanol (0.2 mg kg–1) and midazolam (0.1 mg kg–1) sedation, cats were randomly assigned to receive either alfaxalone or propofol for induction of anaesthesia and sevoflurane maintenance. Cats were anaesthetized daily with the same induction agent for 10–12 days. Complete blood counts, reticulocytes, Heinz body score and serum biochemistry were performed before the first treatment (T1), at T6, T10 and 3 weeks after the final treatment (T21). Cumulative induction agent dose for each cat at each time point was evaluated for an effect on Heinz body score. Data are shown as mean ± standard deviation; p < 0.05. ResultsAt baseline there were no significant differences in signalment or blood variables between groups. A significant decrease in haematocrit of 2.3% ± 0.77 (p = 0.02) between T1-T6 and T1-T10 [mean 4.1% (± 0.78, p < 0.0001)] was detected, with a significant increase in haematocrit of 2.1% ± 0.80 (p = 0.046) between T6-T21 and 4.0% ± 0.8 (p < 0.001) between T10-T21. Heinz body score significantly increased by 1.86 ± 0.616 (p = 0.013) between T1-T10. In the propofol group, reticulocytes increased significantly between T1-T6 [mean 23,090 μL–1 ± 7670 (p = 0.02)] and T1-T10 [mean 27,440 μL–1 ± 7990 (p = 0.007)]. Mean cumulative dose at T10 was 19.65 mg kg–1 ± 5.3 and 43.4 mg kg–1 ± 14.4 for alfaxalone and propofol, respectively, with no significant effect on Heinz body formation at any time point. Conclusions and Clinical relevanceHaematocrit decreased in both groups with recovery after 3 weeks. Repeated alfaxalone and propofol administration was not associated with marked haematological or serum biochemistry changes.

A randomized clinical trial on effects of alfaxalone combined with medetomidine and midazolam in preventing stress-related neurohormonal and metabolic responses of isoflurane-anesthetized cats undergoing surgery.

To evaluate the effects of IM and IV administration of alfaxalone alone and in combination with medetomidine, midazolam, or both on key stress-related neurohormonal and metabolic changes in isoflurane-anesthetized cats undergoing ovariohysterectomy or castration. 72 client-owned mixed-breed cats undergoing ovariohysterectomy or castration between October 4, 2018, and January 10, 2020. For each type of surgery, cats were assigned to 1 of 6 premedication protocols groups, with 6 cats/group: physiologic saline (0.9% NaCl) solution (0.5 mL, IM) and alfaxalone (5 mg/kg, IV); physiologic saline solution (0.5 mL, IM) and alfaxalone (5 mg/kg, IM); medetomidine (50 μg/kg, IM) and alfaxalone (5 mg/kg, IV); medetomidine (50 μg/kg, IM) and alfaxalone (5 mg/kg, IM); midazolam (0.5 mg/kg, IM), medetomidine (50 μg/kg, IM), and alfaxalone (5 mg/kg, IV); or midazolam (0.5 mg/kg, IM), medetomidine (50 μg/kg, IM), and alfaxalone (5 mg/kg, IM). Venous blood was taken before pretreatment, pre- and postoperatively during anesthesia with isoflurane and oxygen, and during early and complete recovery. Compared with baseline concentrations, plasma adrenaline and noradrenaline concentrations decreased during anesthesia in cats premedicated with alfaxalone alone and in combination with medetomidine. The combination of medetomidine, midazolam, and alfaxalone prevented an excessive increase in catecholamines during anesthesia and surgery in cats. Postoperative plasma cortisol concentration after ovariohysterectomy was lower for cats premedicated with the combination of medetomidine and alfaxalone or the combination of medetomidine, midazolam, and alfaxalone, compared with cats premedicated with alfaxalone alone. Cats treated with combinations that included medetomidine and midazolam had hyperglycemia during anesthesia. Cats treated with medetomidine or medetomidine and midazolam in combination with alfaxalone, compared with alfaxalone alone, had lower concentrations of nonesterified fatty acids during anesthesia. Behavioral recovery scores were lower (better) for cats that received medetomidine in addition to alfaxalone, compared with alfaxalone alone. Results indicated that pretreatments with medetomidine and alfaxalone or with medetomidine, midazolam, and alfaxalone were useful for preventing stress-related hormonal and metabolic responses, other than hyperglycemia, during isoflurane anesthesia and surgery in cats.

Comparison of subcutaneous sedation with alfaxalone or alfaxalone-midazolam in pet guinea pigs (Cavia porcellus) of three different age groups

To compare the cardiorespiratory effects, quality and duration of sedation of 2 subcutaneous sedation protocols for noninvasive procedures in guinea pigs (GPs). 24 pet GPs (15 females, 9 males) of 3 different age groups: infant (n = 8), juvenile (8), and adult (8). The study design was a randomized, crossover, blinded, clinical trial with a washout period of at least 7 days between protocols. Guinea pigs were sedated SC with alfaxalone (5 mg/kg; group A) or alfaxalone (5 mg/kg) and midazolam (0.5 mg/kg; group A + M) to facilitate blood sampling, radiography, or abdominal ultrasonography. Vital parameters, hemoglobin saturation (SpO2), and sedation scores were recorded every 5 minutes. Mean heart rate was lower in group A than group A + M (P = 0.001), and respiratory rate was significantly (P = 0.001) decreased relative to baseline during sedation in both groups. The SpO2 remained above 95% in both sedation groups. Rectal temperature was significantly (P = 0.001) lower during recovery versus baseline. Onset of sedation was shorter and the duration longer in group A + M than in group A. The duration and depth of the sedation was different between age groups (P = 0.001), being longer and deeper in adults. Bruxism, hectic movements, twitching, and some degree of hyperreactivity were observed during 41 of the 48 sedations. Subcutaneous administration of alfaxalone provided reliable sedation for nonpainful procedures in GPs. When combined with midazolam, alfaxalone provided longer and deeper sedation that was more significant in adults than in younger patients.

Maximum volume of nasal administration using a mucosal atomization device without aspiration in Japanese White rabbits.

Recently, a mucosal atomization device (MAD) has been applied in veterinary medicine. In the present study, the maximum volume of nasal atomization without aspiration using MAD was examined in eight healthy female Japanese White (JW) rabbits. Each rabbit had their head and neck examined by computed tomography before and after nasal atomization with four different doses (0.15, 0.3, 0.45, and 0.6 ml per nostril) of diluted contrast medium (1:2 mixture of iohexol and saline). This was done under general anesthesia by an intramuscular administration of alfaxalone 2.5 mg/kg, medetomidine 40 μg/kg, and butorphanol 0.4 mg/kg, with a 7-day washout period between each treatment. The diluted contrast medium was distributed in the nasal cavity, external nares, and/or oral cavity in all rabbits receiving each treatment. The intranasal distribution volumes of the contrast medium were 287 (250–333) mm3 [median (interquartile range)] for 0.15 ml, 433 (243–555) mm3 for 0.3 ml, 552 (356–797) mm3 for 0.45 ml, and 529 (356–722) mm3 for 0.6 ml of treatment. The intranasal distribution volume for 0.15 ml treatment tended to be lower than that for 0.6 ml treatment (P=0.083). The contrast medium was deposited in the trachea in one rabbit (12.5%) and four rabbits (50%) receiving treatments of 0.45 and 0.6 ml per nostril, respectively. The maximum volume of nasal atomization without aspiration into the trachea was 0.3 ml per nostril for the JW rabbits.

OPTIMIZING THE PHARMACODYNAMICS AND EVALUATING CARDIOGENIC EFFECTS OF THE INJECTABLE ANESTHETIC ALFAXALONE IN PRAIRIE RATTLESNAKES (CROTALUS VIRIDIS)

North American vipers are commonly housed in zoological institutions or studied as free-ranging populations. Because of their venomous predatory and defensive mechanism, sedation or anesthesia is frequently employed to facilitate safe handling and medical procedures, especially of the head. A new formulation of alfaxalone with proprietary preservatives was recently approved and indexed for 28-d use post-vial puncture. Pharmacodynamic effects of alfaxalone in its prior formulation have been researched in nonvenomous species, but the optimal dose and route of administration in vipers have not been reported. In part one, 10 prairie rattlesnakes (Crotalus viridis) participated in a complete four-route crossover study evaluating 20 mg/kg alfaxalone administered intracoelomically (ICo), SC cranial to the heart, IM cranial to the heart, and IV in the ventral coccygeal vein. HR significantly decreased from baseline during IV (P= 0.024), IM (P= 0.024), and SC (P= 0.028) administration. Respiratory rate significantly decreased following alfaxalone delivered IV (P = 0.027). Time to first effects was significantly faster in IV compared with IM (P= 0.01), SC (P= 0.001), and ICo (P= 0.036). All IV and IM administrations resulted in deep sedation, but 70% of the IV and 10% of the IM sedation events resulted in apnea and required intermittent positive ventilation via endotracheal tube. Fifty percent of the ICo sedation events and 10% of the SC sedation events did not result in sedation. One successful SC sedation event resulted in apnea. In part two, echocardiograms were performed in the same rattlesnakes at baseline and at maximum effect of sedation with 20 mg/kg alfaxalone administered IM. Cardiac contractility and output were unaffected. Administration of alfaxalone at 20 mg/kg IM cranial to the heart should facilitate safe handling and minimally invasive procedures in prairie rattlesnakes and related species.

Clinical review of the pharmacological and anaesthetic effects of alfaxalone indogs.

This clinical review summarises the pharmacological and anaesthetic properties of alfaxalone in the dog. Available pharmacokinetic-pharmacodynamic data and factors affecting the induction dose have been reported. Furthermore, quality of induction and recovery after alfaxalone administration, the use of alfaxalone for total intravenous anaesthesia, and its effects on the cardio-respiratory system, on laryngeal motion, on intraocular pressure and tear production have been evaluated. Finally, the use of alfaxalone in dogs undergoing caesarean section and the effect of intramuscular alfaxalone administration have been considered.

Induction of General Anesthesia With Alfaxalone in the Domestic Chicken.

Alfaxalone is a safe and effective anesthetic drug for the induction of general anesthesia in many nonavian companion animal species; however, its efficacy has not been fully evaluated in birds. In premedicated trials, the chickens were sedated with butorphanol 2 mg/kg intramuscularly and midazolam 0.5 mg/kg intramuscularly, 15 minutes before intravenous administration of alfaxalone. The chickens were classified as anesthetized if endotracheal intubation was achieved without eliciting a cough reflex, provoking no patient resistance, and with minimal glottis movement within 15 seconds after the administration of alfaxalone. Qualitative and quantitative data were recorded, including duration of anesthesia, quality of induction, quality of recovery, reflexes, time to sternal recumbency, time to standing, and time to normal behaviors. Survival analysis was used to analyze the association between alfaxalone dosage and premedication with time-related variables. Out of the evaluated doses, the lowest intravenous alfaxalone dose required to achieve anesthetic induction and endotracheal intubation in unpremedicated and premedicated chickens was 7.5 and 4 mg/kg, respectively. The duration of anesthesia for all dose rates within the study ranged from 51 seconds to 4 minutes 45 seconds. Premedication generally improved the quality of induction and recovery, but significantly (P < .001) increased the time required for the chickens to stand after being anesthetized and to return to normal behaviors. Most chickens exhibited varying degrees of hyperactivity on anesthetic induction and recovery. No postinduction apnea or deaths of the subject birds occurred during this investigation.

Alfaxalone Successfully Immobilizes Small Indian Mongooses (Urva auropunctata): A Field Report

ABSTRACTWe investigated intramuscular administration of alfaxalone (5.3–10.0 mg/kg) as an immobilizing agent in free‐ranging small Indian mongooses (Urva auropunctata) on the island of St. Kitts, West Indies. From 5–11 January 2020, we successfully immobilized 10 of 11 mongooses. Alfaxalone provided rapid onset (median = 3 min) of immobilization. Mean duration of immobilization was 16.8 ± 3 min. Mean recovery time was 5.6 ± 1 min. There was no effect of dose administered on induction, anesthesia, or recovery times at the dose range used. We concluded that alfaxalone represents an effective alternative to dissociative agents for the immobilization of free‐ranging mongooses. Further studies are necessary to quantify alfaxalone effects on mongoose vital rates and blood parameters. © 2021 The Wildlife Society.

Difference between Cranial and Caudal Intravenous Alfaxalone Administration in Yellow-Bellied Sliders (Trachemys scripta scripta)

Difference between Cranial and Caudal Intravenous Alfaxalone Administration in Yellow-Bellied Sliders (Trachemys scripta scripta)

The Effect of Xylazine Premedication on the Dose and Quality of Anesthesia Induction with Alfaxalone in Goats.

Goats have been used as animal models in research and are increasingly kept as companion animals. However, information about effective anesthetic drugs is scarce in this species. The objective of this study was to evaluate the effect of xylazine premedication on alfaxalone induction. Twelve clinically healthy goats weighing 18.5 ± 2 kg were randomly assigned to two groups. Induction was performed with alfaxalone alone intravenously (ALF group) or with xylazine premedication before alfaxalone administration (XYL-ALF group). The quality of induction was scored, induction doses of alfaxalone were determined, and cardiorespiratory parameters and nociceptive thresholds were measured before any treatment(s) (baseline) and at 5, 15, 25 and 35 min after alfaxalone administration. The mean dose of alfaxalone required for induction in the ALF group was greater than that in the XYL-ALF group (p < 0.001). There were no significant changes in diastolic arterial pressure (DAP), mean arterial pressure (MAP) or systolic arterial pressure (SAP) compared to baseline in either group, while hemoglobin oxygen saturation (SpO2) was lower from 5 to 25 min (p < 0.5) in the XYL-ALF group. The nociceptive threshold was significantly higher at 5 min in the XYL-ALF group than in the ALF group (p = 0.0417). Xylazine premedication reduced the required dose of alfaxalone for anesthetic induction and produced better antinociception than alfaxalone alone. In addition, the combination of xylazine and alfaxalone allowed for successful induction; however, oxygen supplementation is necessary to counteract xylazine-associated hypoxemia.

Sedation Characteristics of Intranasal Alfaxalone in Adult Yucatan Swine.

Compared with intravenous and intramuscular methods, intranasal administration of sedatives is a less invasive and nonpainful technique. In this prospective, randomized, crossover study, we evaluated the sedative characteristics of 2 doses (1 and 2 mg/kg) of alfaxalone administered intranasally to 7 adult Yucatan swine. We compared sedation scores before and after administration of alfaxalone and between groups by using a composite sedation scoring system (range, 0 to 12, with 12 being the highest level of sedation)). Pigs were randomly assigned to receive 2 doses of intranasal alfaxalone (1 mg/kg [A1]); 2 mg/kg [A2]) as 2 separate events in a crossover design with a 60-d washout period. Categories scored were posture, palpebral droop, uninhibited behavior, drowsiness, and acceptance of anesthetic facemask. Sedation scores were collected before sedation was administered and then every 3 min for 30 min afterward. Instilled volumes (mean ± 1 SD) were 5.7 ± 0.5 and 11.3 ± 0.8 mL for A1 and A2, respectively. Both alfaxalone doses produced significant increases in sedation scores compared with baseline. Median sedation scores for A1 (6; range, 4-12) were not different from those for A2 (6; range, 6 to 12). Intranasal administration of alfaxalone as the sole sedative agent increased sedation scores from baseline, achieving peak sedation at 6 to 9 min after instillation of A2. However, sedation scores were similar between the 2 groups, and neither dose produced sufficient sedation to facilitate handling or the performance of any clinical procedures. Given the concentration of alfaxalone solution currently available, volume is the major limiting factor regarding testing higher doses of this drug for its use as a sole sedative agent in swine.

Evaluating the efficacy of alfaxalone in corn snakes (Pantherophis guttatus)

ObjectiveAlfaxalone is a popular veterinary anesthetic; however, research on this anesthetic in snakes has been limited to ball pythons, garter snakes and several Australian species. The objective was to evaluate the anesthetic effects of alfaxalone in corn snakes (Pantherophis guttatus), a popular pet snake. Study designProspective, randomized crossover study. AnimalsA total of eight corn snakes. MethodsIn phase I, snakes were subcutaneously administered three doses of alfaxalone (5, 10 and 15 mg kg–1) in the cranial third of the body to determine the most effective dose. In phase II, a dose of 15 mg kg–1 was administered in the cranial and caudal thirds of the snakes to determine if injection site affected anesthesia duration. Heart rate (HR), respiratory rate (fR), righting reflex, escape response, tail pinch, needle prick and tongue flick were monitored at baseline and 5 minute intervals until the snakes fully recovered. ResultsDuration of anesthesia differed significantly, with higher doses lasting longer than lower doses: 5 mg kg–1 [23.8 ± 4.4 (15–30) minutes]; 10 mg kg–1 [40.6 ± 9.4 (25–55) minutes]; and 15 mg kg–1 [56.9 ± 8.4 (50–70) minutes], mean ± standard deviation (range). The tail pinch reflex was not completely lost in phase 1. There was a significant change in fR over time, but this was not related to dose. HR was not different by time or dose. Duration of anesthesia was not different after administration of alfaxalone (15 mg kg–1) in the cranial third versus the caudal third of the body; however, there was a significant decrease in HR and fR at this dose, regardless of injection site. Conclusions and clinical relevanceBased on these results, alfaxalone (15 mg kg–1) provides adequate anesthesia for brief procedures or intubation; however, additional analgesia is required for painful procedures.