The role of on-site drug analysis within supervised injecting facilities: A case presentation of an adverse event highlighting need.

INTRODUCTION: The Sydney Medically Supervised Injecting Centre provides a safe, non-judgemental space where people can inject pre-obtained substances under the supervision of trained staff. This article describes an unusual incident occurring at the Medically Supervised Injecting Centre in January 2023. CASE PRESENTATION: Two regular male clients attending the Medically Supervised Injecting Centre injected a substance they believed to be cocaine. Both clients experienced adverse reactions; one was transported to hospital, while the other became extremely distressed and agitated. Paraphernalia sent for testing returned a result of tiletamine (a dissociative used in veterinary medicine) and no cocaine, 30 h after the incident. DISCUSSION AND CONCLUSIONS: Where substances are novel or unknown, adverse events are often unexpected and may be more difficult to prepare for. Substance-induced acute agitation can be alarming and hazardous for people consuming drugs and those around them and may pose challenges for staff. There is a substantial evidence base for the benefits of on-site drug analysis and drug checking in reducing harms related to drug use, and in enhancing drug market monitoring. This incident was successfully managed by Medically Supervised Injecting Centre and hospital staff, with no major consequence, however clinical management could have been improved using point of care drug testing.

Retrospective Comparison of the Anesthetic Effects of Tiletamine-Zolazepam with Dexmedetomidine and Ketamine with Dexmedetomidine in Captive Formosan Serow (Capricornis swinhoei).

Formosan serows are endemic to the mountainous regions of Taiwan. This crossover study aimed to assess and compare the anesthetic induction and recovery using either dexmedetomidine-tiletamine-zolazepam (DZ) or dexmedetomidine-ketamine (DK) by intramuscular injection from a blow-dart in a zoo environment. Ten anesthetic procedures were performed with five adult Formosan serows. Each participant was anesthetized with both combinations at least once with a minimal 12-month washout. The average dosages were 22.6 ± 8.3 µg/kg and 35.8 ± 2.5 µg/kg for dexmedetomidine and 185.6 ± 123.6 and 357.8 ± 25.2 µg/kg for atipamezole for the DZ and DK groups, respectively. The doses of tiletamine-zolazepam and ketamine were 2.1 ± 0.25 mg/kg and 3.6 ± 0.3 mg/kg, respectively, in the DZ and DK groups. All participants were induced within 10 min (median: 8 min for both groups), except one serow in the DK group with an induction time of 22 min. Serows in the DZ group had a lower respiratory rate (p = 0.016) and lower rectal temperature (p = 0.008) than those in the DK group. The quality of recovery was poor for DZ because of paddling, prolonged recovery, and ataxia after antagonism of dexmedetomidine with atipamezole. The induction of anesthesia with dexmedetomidine-tiletamine-zolazepam was uneventful and rapid. However, recovery from this combination was not smooth.

EVALUATION OF A COMBINATION OF TILETAMINE-ZOLAZEPAM, MEDETOMIDINE, AND AZAPERONE WITH NASAL OXYGEN SUPPLEMENTATION FOR THE IMMOBILIZATION OF CAPTIVE CHACOAN PECCARIES (CATAGONUS WAGNERI) IN THE CHACO REGION OF PARAGUAY.

A combination of tiletamine-zolazepam, medetomidine, and azaperone was used to immobilize captive Chacoan peccaries (Catagonus wagneri) for health assessments and biological sample collection at the Centro Chaqueño para la Conservación e Investigación (CCCI) in the Paraguayan Chaco during July in 2017 and 2018. In total, 83 peccaries kept in 0.25-1.50 hectare enclosures were immobilized via dart-administered anesthetic. Mean animal weight was 33.89±3.74 kg (standard deviation; n=77). The mean intramuscular (IM) anesthetic drug and dosages were 0.03±0.00 mg/kg of medetomidine, 0.91±0.10 mg/kg of Zoletil 50 (tiletamine-zolazepam), and 0.30±0.03 mg/kg azaperone. The mean time to recumbency after darting was 6.07±2.65 min. The mean time to reach the anesthetic plane postdarting was 10.00±2.00 min. Muscle relaxation was adequate to allow minor veterinary procedures. A mean dosage of 0.15±0.02 mg/kg of atipamezole was given IM to reverse the medetomidine. Recoveries were smooth and animals were standing by 59.17±30.18 min postreversal. Full recovery and release back to enclosures occurred 90±30 min postreversal. A single dose of this drug combination provided adequate anesthesia for 88% of adult Chacoan peccaries; 12% needed a supplemental dose of tiletamine-zolazepam because of failure to receive the full dose from the anesthetic dart. Sex and age did not impact the dosage required to achieve immobilization. Confinement during recovery from anesthesia is required with this protocol. Aside from mild hypoxemia, no adverse effects from anesthesia were observed. However, oxygen supplementation as a part of this protocol is recommended to support circulatory and respiratory capacity.

Effects of tiletamine-zolazepam vs. propofol on peri-induction intraocular pressure in dogs: A randomized, masked crossover study.

Introduction: Anesthesia induction agents have the potential to cause severe ocular side effects, resulting in lasting damage to the eye. Objectives: The purpose of this study is to determine the effects of tiletamine-zolazepam on IOP compared to propofol when they are used as an induction agent in normal healthy dogs. Methods: Twenty healthy adult client owned dogs weighing 22.2 ± 7.6 kg were selected for the study. In a randomized order, all dogs received tiletamine-zolazepam 5 mg/kg IV or propofol 8 mg/kg IV titrated to effect without premedication. Washout between each treatment was at least seven days. IOP measurements were obtained at four time points: baseline, post-induction, post-intubation, and after recovery using applanation tonometry. No additional procedures were performed. After normality of the data was determined, a linear mixed model was built with time, eye, treatment and all interactions of those variables as fixed effects and subject as a random effect. Results: There was no significant difference for age, body weight, drug dose, baseline IOP, and recovery IOP between treatments. Average IOP measurements remained within the normal range of 15-25 mmHg at these time points. However, IOP was significantly less elevated by the tiletamine-zolazepam treatment vs. propofol at the post-induction (mean difference: -4.7 ± 4.6 [95%CI -6.8 to -2.5]) and the post-intubation (mean difference: -4.4 ± 4.6 [95%CI -6.5 to -2.2]) time points. Clinical significance: Dogs receiving tiletamine-zolazepam for anesthetic induction had a significantly less elevated IOP at induction and intubation compared to dogs receiving propofol.

Evaluation of Anesthetic and Cardiorespiratory Effects after Intramuscular Administration of Three Different Doses of Telazol® in Common Marmosets (Callithrix jacchus).

Marmosets' small body size makes anesthesia challenging. Ideally, small volumes of drugs should be administered intramuscularly (i.m.). In addition, dose-dependent sedation and anesthesia are desirable properties for sedatives and anesthetics in marmosets. Telazol® (tiletamine and zolazepam) is highly concentrated, allowing the use of small injection volumes and dose-dependent sedation and anesthesia. A randomized, blinded study with crossover design in ten healthy adult common marmosets (Callithrix jacchus) was performed to evaluate the anesthetic and cardiorespiratory effects of three doses of i.m. Telazol® (respectively, 5, 10, and 15 mg/kg). Depth of anesthesia, cardiorespiratory effects, and induction, immobilization, and recovery times were determined. A significant difference was observed in immobilization time between 5 and 15 mg/kg of Telazol®. In addition, 15 mg/kg of Telazol® resulted in increased recovery times compared to 5 mg/kg. The cardiorespiratory effects during the first 45 min of immobilization were within clinically acceptable limits. The pedal withdrawal reflex was the best indicator of the anesthetic depth.

Changes in spontaneous and odorant-induced single-unit activity of mitral/tufted neurons of the rat olfactory bulb during xylazine-tiletamine-zolazepam anesthesia.

The nature and severity of mitral/tufted (M/T) cells reactions to odorants presented in anesthesia depend on various factors, and, above all, the nature and concentration of the odor, anesthesia, and the functional state of the olfactory bulb (OB). Compared to wakefulness, under anesthesia, the intensity of OB M/T cells responses to the odorants presented increases. However, the influence of anesthesia dynamics on the intensity of such responses has not been studied. To address this problem in rats, the activity of M/T cells and the local field potentials (LFP) in OB were recorded in the course of xylazine-tiletamine-zolazepam (XTZ) anesthesia. It has been shown that in the course of the anesthesia, the average frequency of background and odorant-induced single-unit activity of M/T cells increases, while the dominant frequency value of LFP in the gamma frequency range (90-170 Hz), on the contrary, decreases. The observed effects are assumed to be associated with changes in the functional state of the OB and systems for processing olfactory information in anesthesia.

Field Evaluation of Tiletamine-Zolazepam-Medetomidine for Immobilization of Raccoons (Procyon lotor) and Striped Skunks (Mephitis mephitis).

The effectiveness of tiletamine-zolazepam (1.7 mg/kg) plus medetomidine (0.07 mg/kg; TZM) as an immobilizing combination in raccoons (Procyon lotor; n=43) and striped skunks (Mephitis mephitis; n=7) was evaluated during October 2019. Mean (±SD) induction time for raccoons was 15.0±6.6 min. First signs of recovery (head up) occurred 12.9±6.0 min after receiving atipamezole reversal (0.35 mg/kg) and animals were standing in 30.3±16.1 min. Mean induction time for skunks was 11.7±5.8 min. Following reversal, skunks first raised their heads in 6.7±4.3 min and stood in 17.1±12.9 min. Recovery in skunks and female raccoons was not related to length of time immobilized, but male raccoons that were immobilized for longer periods of time stood faster after reversal. Raccoon heart rate (HR) remained steady during immobilization, but respiration rate (RR) and rectal temperature (RT) declined. The HR and RR were similar among males and females, but RT of male raccoons were, on average, 0.5 C higher than those of females, and rate of temperature decline was slower for males. The HR, RR, and RT of skunks declined during immobilization. Although induction times for both raccoons and skunks were longer than expected, induction and recovery were smooth, side effects were few, analgesia was adequate for nonsurgical procedures, and reversal reduced time in captivity.

Clinical Usefulness of the Anaesthetic Protocol Using Low Doses of Tiletamine - Zolazepam Combination in Continuous Rate Infusion as a Partial Intravenous Anaesthesia in Bitches Undergoing Laparoscopic Surgery.

The objective of this study was to evaluate the clinical usefulness of the combination of tiletamine-zolazepam used in low doses as a continuous rate infusion in a partial intravenous anesthesia protocol. Fifteen clinically healthy, different breed bitches weighing 25.08 ± 10.39 kg was used in this study. After a food fast for at least 12 hours and water fast for 4 hours, the animals were premedicated with dexmedetomidine. After 15 minutes, the bolus of tiletamine-zolazepam combination was given as an. Induction of general anesthesia, immediately followed by continuous intravenous infusion. The following parameters were measured immediately after the induction of general anesthesia and lasted until the end of the surgery: electrocardiography, heart rate, systolic arterial blood pressure, diastolic arterial blood pressure, mean arterial blood pressure, body temperature respiratory rate end tidal of CO2. During the recovery period, pain level was evaluated as well as sedation assessment. Time for successful intubation after administration of the tiletamine-zolazepam combination was within 3 minutes. Heart rate was within reference values. Systolic, diastolic, and mean arterial blood pressure were also within the reference values. Internal body temperature showed a downward trend for a whole procedure time. During recovery, only 1 patient showed symptoms of pain and signs of dissociation. In summary, the partial intravenous protocol with the use of tiletamine-zolazepam combination and low anesthetic gases concentration is clinically useful because of ensuring the correct level of anesthesia and stability of intraoperative parameters as well as a good recovery period.

Intraocular pressure and cardiovascular effects of dexmedetomidine premedication and tiletamine-zolazepam for anesthetic induction in dogs.

Background and Aim: The effect of anesthetic drugs on intraocular pressure (IOP) is an important concern in ophthalmic surgery. The impact of dexmedetomidine (DEX) combined with tiletamine-zolazepam on IOP is scarcely studied. This study aimed to evaluate IOP and cardiovascular effects in dogs after premedication with 5 µg/kg (DEX5) or 10 µg/kg (DEX10) of intramuscular DEX followed by intravenous tiletamine-zolazepam administration for induction of anesthesia in healthy dogs. Materials and Methods: Eighteen dogs, American Society of Anesthesiologists I or II, without ocular abnormality were investigated. All dogs were randomly divided into the DEX5 (n = 9) and DEX10 groups (n = 9). The IOP, heart rate (HR), systolic blood pressure (SBP), oxygen saturation, and sedation scale were measured before premedication (baseline), after premedication at 5, 10, 15, and 20 min, after tiletamine-zolazepam administration, after endotracheal intubation, and post-operative. Results: There were no significant differences between the groups at any time point. The DEX5 and DEX10 groups had significantly decreased HR values at 10 min compared with baseline. The IOP at 20 min was significantly lower compared to the baseline in the DEX10 group. Moreover, the DEX10 group showed increased IOP, HR, SBP, and sedation scale values after induction and intubation compared with 20 min, but these values did not differ significantly from baseline. All parameters of both groups did not change significantly between post-operative and baseline. Conclusion: Intramuscular DEX (10 µg/kg) is an appropriate premedication in ophthalmic examination or surgical procedures. Moreover, it could be combined with tiletamine-zolazepam for generalized anesthesia in dogs with an ophthalmic problem, as it had no clinically significant effects on IOP or cardiovascular values.

Dissociative anaesthesia in dogs and cats with use of tiletamine and zolazepam combination. What we already know about it.

This article is an attempt to gather available literature regarding the use of tiletamine and zolazepam combination in anaesthesia in dogs and cats. Although tiletamine and zolazepam mixture has been known in veterinary practice for a long time, the increased interest in these drugs has been observed only recently. Tiletamine, similarly to ketamine, is a drug which belongs to the phencyclidine group. Ketamine has considerable popularity in veterinary practice what suggests that other dissociative anaesthetic drugs, such as tiletamine, could also prove effective in cats' and dogs' anaesthetic care. Zolazepam is a widely used benzodiazepine known for its muscle relaxant and anticonvulsant properties. While conducting an electronic search for articles regarding the use of tiletamine-zolazepam combination in dogs and cats, it has been discovered that the literature on the subject (tiletamine-zolazepam combination in dogs and cats) is quite scarce. Very few articles were published after 2010. Databases used were: Google Scholar, Scopus, PubMed. Most of the adverse effects, including those affecting the cardiovascular, nervous, and respiratory systems, were strictly dose-dependent. Tiletamine-zolazepam combination can be safely used as a premedication agent, induction for inhalation anaesthesia, or an independent anaesthetic for short procedures. Contraindications using tiletamine-zolazepam mixture include central nervous system (CNS) diseases such as epilepsy and seizures, head trauma, penetrative eye trauma, cardiovascular abnormalities (hypertrophy cardiomyopathy in cats, arrythmias or conditions where increase of heart rate is inadvisable), hyperthyroidism, pancreatic deficiencies or kidney failure.

Voluntary Oral Ingestion of a Sedative Prior to Euthanasia with CO2: Behavioural Responses of Mice.

Laboratory mice are commonly euthanised with carbon dioxide (CO2); however, there is ample evidence that this gas is aversive. Previous work suggests that sedation achieved via injection with benzodiazepines prior to CO2 administration could reduce aversive behaviours during euthanasia. We explored the potential of using a voluntarily ingested sedative (tiletamine-zolazepam, Zoletil®) prior to euthanasia. Male and female C57BL/6 mice were allocated into one of the five experimental groups, which differed in the dose of Zoletil: 0, 10, 20, 40, 80 or 100 mg/kg. A dose of 20 mg/kg was found to achieve mild sedation prior to euthanasia; mice which received this dose numerically reared and walked on the cage lid less, and showed ataxia, immobility and recumbency for longer than mice that received a lower dose. During euthanasia, mice that received 20 mg/kg showed fewer aversive responses to CO2. Doses of 40 to 100 mg/kg were associated with signs of moderate to severe sedation, but resulted in an incomplete intake of the sedative, which made the interpretation of the aversiveness to CO2 difficult. Voluntary oral administration of a sedative is an effective, affordable, and easy way to minimize the stress of mice to euthanasia with CO2.

Cardiopulmonary (No Ventilation) and Anesthetic Effects of Dexmedetomidine-Tiletamine in Dogs.

The aim of the present study was to evaluate the anesthetic and cardiopulmonary effects of dexmedetomidine in combination with tiletamine (without zolazepam) as a general anesthetic. The study was divided into two phases. In Phase 1, 18 adult healthy mixed-breed dogs were randomly allocated into three groups: Group TD8 (4.5 mg kg-1 tiletamine and 8 µg kg-1 dexmedetomidine), Group TD10 (4.5 mg kg-1 tiletamine and 10 µg kg-1 dexmedetomidine), or Group TD12 (4.5 mg kg-1 tiletamine and 12 µg kg-1 dexmedetomidine). After drug administration, the heart rate (HR), respiratory rate (f R), mean arterial pressure (MAP), systolic arterial pressure (SAP), diastolic arterial pressure (DAP), peripheral hemoglobin oxygen saturation (SpO2), behavioral score, quality of induction and recovery, extent of ataxia, the time taken for induction, and the duration of anesthesia were recorded. The recovery time and quality were recorded after administration of atipamezole (50 µg kg-1) after 60 min. In phase 2, the feasibility of combining dexmedetomidine (10 µg kg-1) and tiletamine (4.5 mg kg-1) as general anesthetics for orchiectomy was evaluated in dogs (n = 6). HR, f R, MAP, SAP, DAP, temperature, SpO2, behavioral scores, and adverse reactions were recorded during each surgical procedure. In phase 1, the dogs were anesthetized for 5 min after administration of drugs and achieved a maximum behavioral score in TD10 and TD12 after 10 min. Although HR, MAP, SAP, DAP, and NIBP decreased in all three groups, they still maintained within the normal range. In phase 2, orchiectomy was completed smoothly in all dogs with little fluctuation in the physiological variables. We found that a combination of tiletamine (4.5 mg kg-1) and dexmedetomidine (10 µg kg-1) intramuscularly induced moderate anesthesia in dogs and could be utilized for short-term anesthesia and minor surgery.

Intravenous zoletil administration for the purpose of suicide.

Zoletil is a combination of tiletamine hydrochloride and zolazepam hydrochloride used as a veterinary anesthetic. Although zoletil abuse is widely known, zoletil poisoning for the purpose of suicide is very rare. We present a case of a 39-year-old man who attempted suicide by intravenously injecting a large amount of zoletil, resulting in decreased mental status and severe respiratory depression. Intubation and mechanical ventilation were applied. After 30 hours in the hospital, all symptoms of poisoning improved. Because zoletil can cause severe respiratory depression, close observation and aggressive securement of an airway is mandatory.

Evaluation of intramuscular anesthetic protocols in healthy domestic horses.

OBJECTIVE: To assess anesthetic induction, recovery quality and cardiopulmonary variables after intramuscular (IM) injection of three drug combinations for immobilization of horses. STUDY DESIGN: Randomized, blinded, three-way crossover prospective design. ANIMALS: A total of eight healthy adult horses weighing 470-575 kg. METHODS: Horses were administered three treatments IM separated by ≥1 week. Combinations were tiletamine-zolazepam (1.2 mg kg-1), ketamine (1 mg kg-1) and detomidine (0.04 mg kg-1) (treatment TKD); ketamine (3 mg kg-1) and detomidine (0.04 mg kg-1) (treatment KD); and tiletamine-zolazepam (2.4 mg kg-1) and detomidine (0.04 mg kg-1) (treatment TD). Parametric data were analyzed using mixed model linear regression. Nonparametric data were compared using Skillings-Mack test. A p value <0.05 was considered statistically significant. RESULTS: All horses in treatment TD became recumbent. In treatments KD and TKD, one horse remained standing. PaO2 15 minutes after recumbency was significantly lower in treatments TD (p < 0.0005) and TKD (p = 0.001) than in treatment KD. Times to first movement (25 ± 15 minutes) and sternal recumbency (55 ± 11 minutes) in treatment KD were faster than in treatments TD (57 ± 17 and 76 ± 19 minutes; p < 0.0005, p = 0.001) and TKD (45 ± 18 and 73 ± 31 minutes; p = 0.005, p = 0.021). There were no differences in induction quality, muscle relaxation score, number of attempts to stand or recovery quality. CONCLUSIONS AND CLINICAL RELEVANCE: In domestic horses, IM injections of tiletamine-zolazepam-detomidine resulted in more reliable recumbency with a longer duration when compared with ketamine-detomidine and tiletamine-zolazepam-ketamine-detomidine. Recoveries were comparable among protocols.

Comparison of two injectable anaesthetic techniques on induction and subsequent anaesthesia in pigs.

Pig experiments often require anaesthesia, and a rapid stress-free induction is desired. Induction drugs may alter the subsequent anaesthesia. Therefore, the aim of the present study was to compare, in pigs, the effects of two different injectable anaesthetic techniques on the induction and on the physiological variables in a subsequent eight hours of total intravenous anaesthesia (TIVA). Twelve domestic castrates (Swedish Landrace/Yorkshire) 27‒31 kg were used. The pigs were randomly assigned to different induction drug combinations of zolazepam-tiletamine and medetomidine intramuscularly (ZTMe) or midazolam, ketamine intramuscularly and fentanyl intravenously (MiKF). Time from injection to unconsciousness was recorded and the ease of endotracheal intubation assessed. The TIVA infusion rate was adjusted according to the response exhibited from the nociceptive stimulus delivered by mechanically clamping the dewclaw. The time from injection to unconsciousness was briefer and intubation was easier in the ZTMe group. Results from the recorded heart rate, cardiac index and arterial blood pressure variables were satisfactorily preserved and cardiovascular function was maintained in both groups. Shivering was not observed in the ZTMe group, but was observed in four of the pigs in the MiKF group. The requirement of TIVA was lower in the ZTMe group. In conclusion, ZTMe had better results than MiKF in areas such as shorter induction time, better intubation scoring results and less adjustment and amount of TIVA required up to six hours of anaesthesia. The results may have been due to a greater depth of anaesthesia achieved with the ZTMe combination at the dose used.

Physiologic and blood gas effects of xylazine-ketamine versus xylazine-tiletamine-zolazepam immobilization of white-tailed deer before and after oxygen supplementation: a preliminary study.

OBJECTIVE: To compare oxygenation and ventilation in white-tailed deer (Odocoileus virginianus) anesthetized with two treatments with and without oxygen supplementation. STUDY DESIGN: Randomized, blinded, crossover study. ANIMALS: A total of eight healthy adult white-tailed deer weighing 49-62 kg. METHODS: Each deer was anesthetized twice intramuscularly: 1) treatment XK, xylazine (2 mg kg-1) and ketamine (6 mg kg-1) and 2) treatment XTZ, xylazine (2 mg kg-1) and tiletamine-zolazepam (4 mg kg-1). With the deer in sternal position, arterial and venous blood was collected before and at 30 minutes during administration of oxygen at 1 L minute-1 through a face mask. PaO2 and heart rate (HR) were compared using two-way repeated measures anova. pH, PaCO2 and lactate concentration were analyzed using mixed-effects linear models, p < 0.05. RESULTS: When breathing air, PaO2 was < 80 mmHg (10.7 kPa) in six and seven deer with XK and XTZ, respectively, and of these, PaO2 was < 60 mmHg (8.0 kPa) in three and five deer, respectively. With oxygen supplementation, PaO2 increased to 128 ± 4 and 140 ± 5 mmHg (17.1 ± 0.5 and 18.7 ± 0.7 kPa), mean ± standard error, with XK and XTZ, respectively (p < 0.001). PaO2 was not significantly different between treatments at either time point. HR decreased during oxygen supplementation in both treatments (p < 0.001). Lactate was significantly lower (p = 0.047) with XTZ than with XK (2.2 ± 0.6 versus 3.5 ± 0.6 mmol L-1) and decreased (p < 0.001) with oxygen supplementation (4.1 ± 0.6 versus 1.6 ± 0.6 mmol L-1). PaCO2 increased in XTZ during oxygen breathing. CONCLUSIONS AND CLINICAL RELEVANCE: Treatments XK and XTZ resulted in hypoxemia, which responded to oxygen supplementation. Both treatments are suitable for immobilization of white-tailed deer under the study circumstances.

Comparison of anesthetic effects of tiletamine-zolazepam-medetomidine or ketamine-medetomidine in captive Amur leopard cats (Prionailurus bengalensis euptailurus).

OBJECTIVE: To evaluate the effects and utility of tiletamine-zolazepam-medetomidine (TZM) and ketamine-medetomidine (KM) for anesthesia of Amur leopard cats (Prionailurus bengalensis euptailurus). STUDY DESIGN: Prospective, randomized experimental trial. ANIMALS: A total of six female (3.70 ± 0.49 kg) and six male (5.03 ± 0.44 kg; mean ± standard deviation) Amur leopard cats aged 2-6 years. METHODS: Each animal was administered four protocols separated by ≥3 weeks. Each protocol included medetomidine (0.05 mg kg-1) combined with tiletamine-zolazepam (1 mg kg-1; protocol MTZLO); tiletamine-zolazepam (2 mg kg-1; protocol MTZHI); ketamine (2 mg kg-1; protocol MKLO); or ketamine (4 mg kg-1; MKHI) administered intramuscularly. At time 0 (onset of lateral recumbency) and 30 minutes, heart rate (HR), respiratory rate (fR), rectal temperature, noninvasive mean arterial pressure (MAP) and hemoglobin oxygen saturation (SpO2) were recorded. Times to onset of lateral recumbency, duration of anesthesia and time to standing were recorded. RESULTS: Overall, animals were anesthetized with all protocols within 10 minutes, anesthesia was maintained ≥57 minutes, and recovery (time from the first head lift to standing) was completed within 5 minutes. During anesthesia with all protocols, HR, fR, rectal temperature, SpO2 and MAP were 99-125 beats minute-1, 33-44 breaths minute-1, 37.6-39.4 °C, 90-95% and 152-177 mmHg, respectively. No adverse event was observed. CONCLUSIONS AND CLINICAL RELEVANCE: TZM and KM at various dosages resulted in rapid onset of anesthesia, duration of >57 minutes and rapid recovery without administration of an antagonist. Accordingly, all these combinations are useful for anesthetizing Amur leopard cats and for performing simple procedures. However, the low doses of the anesthetic agents are recommended because there was no difference in duration of anesthesia between the dose rates studied.

Long-term deep sedation using Zoletil and haloperidol for the treatment of streptococcal pneumonia in an orangutan (Pongo pygmaeus).

A 13-year-old Bornean orangutan diagnosed with life threatening Streptococcus pyogenes broncho-pneumonia was kept in a state of deep sedation for 20 days via continuous intra-venous (IV) infusion of zolazepam -tiletamine and IV haloperidol to allow consistent IV administration of ceftazidime and gatifloxacine. The use of long-term deep sedation allowed carrying out a particularly demanding treatment not generally associated with zoological patients. The treatment was ultimately successful.

Field Anesthesia of the Maned Wolf (Chrysocyon brachyurus) in Bolivia.

Fifteen maned wolves (Chrysocyon brachyurus) were anesthetized a total of 43 times as part of a long-term ecology and health study in a remote region of northeastern Bolivia. We administered tiletamine-zolazepam (TZ) to wolves in box traps or free-ranging, from blinds or on foot, at a mean dosage of 4.6 mg/kg intramuscularly. Detailed anesthetic information was recorded in 24 of these events in 11 wolves (six males, five females), and wolves were monitored closely post procedure with very high frequency or global positioning system telemetry collars. Anesthetic induction was smooth and rapid in all cases, with a mean 6.4 min from injection to recumbency. Vital parameters were stable during the majority of procedures. As expected with this drug combination, recovery was long (mean time to standing 163 min [range: 80-235 min]) but smooth, and animals were monitored in most cases in box traps until stable for release. One case of apnea and prolonged recovery is reported. In two cases, wolves recovered normally but were found to move minimally in the 2.5-4 d postprocedure before resuming normal movements. Overall, TZ provided safe, stable immobilization of free-ranging maned wolves in remote and extreme field conditions, although postanesthesia monitoring via telemetry is recommended.

Tiletamine/zolazepam and dexmedetomidine with tramadol provide effective general anesthesia in rats.

Background: Tiletamine/zolazepam is a dissociative anesthetic combination commonly used in small animals but information is limited in rats. The alpha-2 agonist, dexmedetomidine, has gained popularity in laboratory animal anesthesia. Tramadol is a weak opioid mu agonist. The aim of this study was to assess whether the tiletamine/zolazepam/dexmedetomidine (ZD) combination effectively provides a surgical anesthesia plane comparable to tiletamine/zolazepam/dexmedetomidine with tramadol (ZDT) in a minor procedure in rats. Methods: Rats were induced with ZD or ZDT. After the loss of paw withdrawal, a small incision was made on the rats' left thighs as a surgical stimulus. Rats were maintained under a surgical anesthesia plane by assessing the loss of the paw withdrawal reflex for 45 minutes, then atipamezole was administered. Monitored anesthesia parameters included: (a) physiological parameters - pulse rate (PR), respiratory rate (RR), tissue oxygen saturation (%SpO2), and body temperature; (b) duration parameters - induction time, onset and duration of surgical anesthesia plane, onset of recovery, and recovery time. Results: PR was significantly lower at 10 minutes in ZD and 5 minutes in ZDT groups. No difference was observed for RR, %SpO2, and body temperature. Likewise, there were no differences for duration parameters: induction time was less than 3 minutes; onset and duration of surgical anesthesia plane were approximately 5 and 45 minutes, respectively; onset of recovery (time to move) was 51 minutes; and recovery time was 52 minutes, respectively. Conclusion: These data suggest the ZD combination provides a surgical anesthesia plane comparable to ZDT in a rat incisional pain model.