Hematologic changes associated with Adderall toxicity in a dog

A 1-year-old intact male Boxer was presented to the Texas Veterinary Medical Center for emergency treatment following suspected ingestion of a large number of tablets of Adderall, a pharmaceutical amphetamine. The dog had a temperature of 41.7 degrees C, heart rate of 192 beats per minute, and a respiratory rate of 100 breaths per minute. The dog was anxious and agitated with bilaterally dilated pupils, and shortly thereafter became recumbent and incontinent. Initial CBC results included mild leukopenia and mild thrombocytopenia. The dog was not anemic (HCT 39.9%) and had only slight polychromasia, but had 48 nucleated RBCs/100 WBC (7500/microL). Moderate numbers of neutrophils had hypersegmented nuclei and several pyknotic cells were noted. The metarubricytosis persisted for approximately 56 hours while hypersegmentation and pyknotic cells were no longer found at 8 hours after presentation. The dog received supportive care and recovered uneventfully. We hypothesized that hyperpyrexia associated with Adderall toxicity resulted in inappropriate metarubricytosis due to damaged bone marrow endothelium, and resulted in hypersegmentation and pyknosis due to damaged or accelerated aging of neutrophils in peripheral blood. Metarubricytosis has been reported previously in dogs with heat-induced illness, such as heat stroke.     

Cardiovascular and pulmonary effects of atropine reversal of oxymorphone-induced bradycardia in dogs.

Oxymorphone was administered intravenously (IV) to 10 dogs (0.4 mg/kg initial dose followed by 0.2 mg/kg three times at 20-minute intervals). Four hours after the last dose of oxymorphone, heart rates were less than 60 bpm in six dogs. After atropine (0.01 mg/kg IV) was administered, heart rate decreased in five dogs and sinus arrhythmia or second degree heart block occurred in four of them. A second injection of atropine (0.01 mg/kg IV) was administered 5 minutes after the first and the heart rates increased to more than 100 bpm in all six dogs. Ten minutes after the second dose of atropine, heart rate, cardiac output, left ventricular minute work, venous admixture, and oxygen transport were significantly increased, whereas stroke volume, central venous pressure, systemic vascular resistance, and oxygen extraction ratio were significantly decreased from pre-atropine values. The PaCO2 increased and the PaO2 decreased but not significantly. The oxymorphone-induced bradycardia did not produce any overtly detrimental effects in these healthy dogs. Atropine reversed the bradycardia and improved measured cardiovascular parameters.     

Treatment of virulent footrot with lincomycin and spectinomycin

A mixture of lincomycin and spectinomycin was investigated as a treatment for footrot in sheep. In a controlled clinical trial 92.5% of acute and chronic cases of virulent footrot were cured following a single intramuscular injection of a mixture containing 50 mg lincomycin and 100 mg spectinomycin/ml at a dose rate of 1 ml/10 kg bodyweight. No improvement in clinical response was observed in groups of sheep treated on 3 successive days with this dose rate nor in another group treated once at a dose rate 1 ml/3.3 kg bodyweight. Cure effectiveness of each of the 3 treatment groups relative to untreated controls was 89%, 95% and 95%. Efficacy of lincomycin/spectinomycin was compared with that of penicillin/streptomycin in the treatment of footrot on 2 farms in south western New South Wales. Assessments made 14 to 17 d after treatment showed that on one farm all 122 ewes treated with lincomycin/spectinomycin had recovered while 170 of 175 ewes treated with penicillin/streptomycin recovered in the same period. On the second farm 87 of 90 ewes treated with lincomycin/spectinomycin recovered, compared with 184 of 190 sheep in the same flock treated with penicillin/streptomycin. Supportive footbathing did not seem to improve the clinical response in either treatment group and the paring done was sufficient only to establish diagnosis and to remove grossly overgrown horn.     

Cardiorespiratory Effects of the Intravenous Administration of Tiletamine-Zolazepam to Dogs

The anesthetic, hemodynamic, and respiratory effects of an intravenously administered 1:1 combination of tiletamine and zolazepam were evaluated in dogs. Each dog received tiletamine-zolazepam (6.6, 13.2, 19.8 mg/kg) on two occasions, once when awake and a second time with residual isoflurane anesthesia while instrumented for the recording of hemodynamic data. Tiletamine-zolazepam administered to conscious dogs resulted in good, rapid induction of anesthesia. Time to sternal recumbency (recovery) was dose-dependent. Character of recovery tended to be better with the lower dose. Tiletamine-zolazepam caused significant increases in heart rate after all doses and significant increases in cardiac output after the two larger doses. All doses caused significant decreases in arterial blood pressure at 1 minute. Arterial blood pressures returned to baseline and then increased significantly above baseline values. The rate of development of left ventricular pressure was significantly decreased 1 minute after the two higher doses, returned to normal, and then was significantly increased above baseline for all doses. Peripheral vascular resistance increased transiently 1 minute after the 6.6 mg/kg dose. Peripheral vascular resistance decreased significantly after the 13.2 and 19.8 mg/kg doses. Minute ventilation was significantly decreased only after the 19.8 mg/kg dose.     

The Effects of Atropine and Glycopyrrolate on Heart Rates in Conscious Mature Goats

The effects of intravenously administered atropine (0.2 mg/kg) and glycopyrrolate (0.01 mg/kg) on heart rate were studied in 10 conscious mature goats. In a drug cross-over fashion, either atropine, glycopyrrolate, or 0.9% saline solution was administered using the same volume (0.05 mL/kg). Atropine and glycopyrrolate caused a significant increase in heart rate ( P <.05), whereas saline solution (0.09%) did not. The mean percent changes in heart rate from baseline were similar for atropine and glycopyrrolate up to 14 minutes after administration. Thereafter, glycopyrrolate had a significantly greater mean change in heart rate than atropine, ie, up to 29 minutes ( P <.05). Within the atropine group, the mean percentage changes in heart rate became significantly lower compared with the initial increase (1 minute) starting at 11 minutes. For the glycopyrrolate group, the mean percent changes became significantly lower starting at 27 minutes. Glycopyrrolate and atropine had a mean percentage change in heart rate of greater than 1.0%, up to 31 and 22 minutes, respectively. At the doses used, glycopyrrolate had longer duration of action than atropine but the magnitude of increase was similar.     

Pharmacokinetics and clinical efficacy of a cinchophen and prednisolone combination in the dog

The kinetics and efficacy of a cinchophen prednisolone combination preparation (PLT) were assessed in the dog. Cinchophen administered at a dose rate of 12-5 mg/kg intravenously had a volume of distribution (Vd area) of 0–13 litres/kg, a clearance rate (Cl) of 0–15 litres/h and a half-life (t _1/2β of 7–92 hours. Following oral administration the bioavailability was 87-21 per cent. Prednisolone administered at a dose rate of 0–15 mg/kg intravenously had a Vd area of 2–7 litres/kg, a CI of 0–116 litres/h and a t_1/2β of 1–11 hours. PLT given to dogs with osteoarthritis at a dosage range of between 25 and 44 mg/kg per day cinchophen and between 0–125 and 0–220 mg/kg per day prednisolone for a maximum of 14 days significantly improved lameness (P<0–001), weight bearing (P<0–005), joint mobility (P<0–01) and stiffness (P<0–001) scores and was similar in clinical efficacy to phenylbutazone.     

Total intravenous anaesthesia with propofol or propofol/ketamine in spontaneously breathing dogs premedicated with medetomidine

The cardiorespiratory parameters, the depth of anaesthesia and the quality of recovery were evaluated in six spontaneously breathing dogs that had been premedicated with medetomidine (40 microg/kg, supplemented with 20 microg/kg an hour later), administered with either propofol (1 mg/kg followed by 0.15 mg/kg/minute, intravenously), or with ketamine (1 mg/kg followed by 2 mg/kg/hour, intravenously) and propofol (0.5 mg/kg followed by 0.075 mg/kg/minute, intravenously). The dogs' heart rate and mean arterial blood pressure were higher and their minute volume of respiration and temperature were lower when they were anaesthetised with propofol plus ketamine, and a progressive hypercapnia leading to respiratory acidosis was more pronounced. When the dogs were anaesthetised with propofol/ketamine they recovered more quickly, but suffered some unwanted side effects. When the dogs were anaesthetised with propofol alone they recovered more slowly but uneventfully.     

Ketamine as a part of anaesthetic management in a dog with twiddler's syndrome

An 11‐year‐old male German shepherd dog was referred for possible pacemaker implantation. A routine 6‐lead electrocardiogram revealed a third‐degree atrio‐ventricular block with a heart rate of 40 to 45 beats/minute. A transvenous pacemaker implantation procedure was scheduled. The dog was premedicated with 10 µg/kg acepromazine and 5 mg/kg pethidine. A dose of 5 mg/kg ketamine and 0·2 mg/kg diazepam were used for induction and isoflurane in O₂ and a constant rate infusion of ketamine (20 to 30 µg/kg/minute) were administered for maintenance of general anaesthesia. Due to a twiddler's syndrome, the pacemaker had to be repositioned. For the second procedure, the same protocol was employed except for a lower dose of ketamine both for induction (3 mg/kg) and constant rate infusion (10 to 15 µg/kg/minute). Ketamine appeared to be useful for both management of anaesthesia and cardiac pacemaker implantation in the absence of a temporary pacemaker.     

The use of intraoperative fentanyl in spontaneously breathing dogs undergoing orthopaedic surgery

Nineteen dogs were assigned randomly to one of three groups. Animals in Group 1 were pre-medicated with acepromazine, 50 μg/kg bodyweight (bwt) intramuscularly (im) and received 10 ml of 0.9 per cent saline intravenously (iv) at the time of skin incision. Dogs in Group 2 were pre-medicated with acepromazine, 50 μg/kg bwt im, and received fentanyl 2 μg/kg bwt iv at skin incision. Dogs in Group 3 were pre-medicated with acepromazine, 50 μg/kg bwt and atropine, 30 to 40 μg/kg bwt, im and received fentanyl, 2 μg/kg bwt iv at skin incision. Pulse rate, mean arterial blood pressure, respiratory rate and end tidal carbon dioxide were measured before and after fentanyl or saline injection. Fentanyl caused a short-lived fall in arterial blood pressure that was significant in dogs premedicated with acepromazine, but not in dogs pre-medicated with acepromazine and atropine. A significant bradycardia was evident for 5 mins in both fentanyl treated groups. The effect on respiratory rate was most pronounced in Group 3, in which four of seven dogs required intermittent positive pressure ventilation (IPPV) for up to 14 mins. Two of six dogs in Group 2 required IPPV, whereas respiratory rate remained unaltered in the saline controls. The quality of anaesthesia was excellent in the fentanyl treated groups; however, caution is urged with the use of even low doses of fentanyl in spontaneously breathing dogs under halothane-nitrous oxide anaesthesia.     

Spontaneous resolution of hypothermia-induced atrial fibrillation in a dog

Objective: To report a case of spontaneous resolution of atrial fibrillation secondary to hypothermia in a dog without detectable heart disease. Case summary: An 8‐year‐old female spayed mixed breed dog presented with a history of prolonged exposure to below freezing environmental temperatures. The dog presented hypothermic (<32°C or <90°F) and minimally responsive to stimuli. The heart rate was 80 beats per minute (bpm) and irregular. Atrial fibrillation was diagnosed. The dog had pale mucous membranes, absent femoral pulses, and no obtainable blood pressure via indirect Doppler technique. Resuscitation fluids were administered and active external warming was instituted. Peripheral edema was observed during the rewarming phase and the irregular heart rate was noted to increase. The atrial fibrillation spontaneously resolved with no specific anti‐arrhythmic therapy. No underlying myocardial disease was found. The recovery of this dog was complete with a subsequent repeat of the echocardiogram and electrocardiogram (ECG) 8‐months later found to be within normal limits.     

Pharmacokinetics and pharmacodynamics of butorphanol in llamas after intravenous and intramuscular administration.

OBJECTIVE: To evaluate disposition of butorphanol after i.v. and i.m. administration, effects on physiologic variables, and analgesic efficacy after i.m. administration in llamas. DESIGN: Nonrandomized crossover study. ANIMALS: 6 healthy adult male llamas. PROCEDURE: Butorphanol (0.1 mg/kg [0.045 mg/lb] of body weight) was administered i.m. first and i.v. 1 month later. Blood samples were collected intermittently for 24 hours after administration. Plasma butorphanol versus time curves were subjected to pharmacokinetic analysis. Two months later, butorphanol (0.1 mg/kg) was administered i.m., and physiologic variables and analgesia were assessed. RESULTS: Extrapolated peak plasma concentrations after i.v. and i.m. administration were 94.8 +/- 53.1 and 34.3 +/- 11.6 ng/ml, respectively. Volume of distribution at steady state after i.v. administration was 0.822 +/- 0.329 L/kg per minute and systemic clearance was 0.050 +/- 0.014 L/kg per minute. Slope of the elimination phase was significantly different, and elimination half-life was significantly shorter after i.v. (15.9 +/- 9.1 minutes) versus i.m. (66.8 +/- 13.5 minutes) administration. Bioavailability was 110 +/- 49% after i.m. administration. Heart rate decreased and rectal temperature increased. Somatic analgesia was increased for various periods. Two llamas became transiently sedated, and 2 became transiently excited after butorphanol administration. CONCLUSIONS AND CLINICAL RELEVANCE: Although i.v. administration of butorphanol results in a short half-life that may limit its analgesic usefulness, the elimination half-life of butorphanol administered i.m. is likely to be clinically useful. The relationship among plasma butorphanol concentration, time, and analgesia differed with the somatic analgesia model; clinically useful analgesia may occur at lower plasma concentrations than those reported here.     

Clinical investigation of remifentanil and propofol for the total intravenous anaesthesia of dogs

Fifteen adult dogs underwent elective ovariectomy. They were premedicated with 0.5 mg/kg methadone and 0.05 mg/kg(-1) atropine administered intramuscularly, and anaesthesia was induced with propofol and maintained with intravenous infusions of remifentanil at 0.6 microg/kg/minute and propofol; the mean (sd) rate of infusion of propofol throughout the period of anaesthesia was 0.33 (0.03) mg/kg/minute. The dogs were ventilated continuously with oxygen while they were anaesthetised. Their haemodynamic parameters were clinically acceptable during the period of anaesthesia. Two dogs received additional atropine to correct bradycardias of less than 60 bpm and several dogs received additional boluses of remifentanil or propofol to maintain an adequate depth of anaesthesia, as determined by a clinical assessment. The mean (range) time to the return of spontaneous respiration after stopping the remifentanil infusion was 11.1 (6.0 to 17.0) minutes, and the mean (range) time to the dogs standing was 38.0 (20.0 to 80.0) minutes. The quality of recovery was good in 12 of the dogs, two showed mild excitation in the immediate postoperative period and the other dog required additional analgesia with methadone.     

Cardiopulmonary effects of romifidine and detomidine used as premedicants for ketamine/halothane anaesthesia in ponies

The cardiopulmonary effects of romifidine at 80 microg/kg (R80) or 120 pg/kg (R120), and detomidine at 20 pg/kg (D20) when used as premedicants for ketamine/halothane anaesthesia were investigated in six ponies. Using a blinded crossover design, acepromazine (0-04 mg/kg) was administered followed by the alpha-2 agonist. Anaesthesia was induced with ketamine at 2.2 mg/kg and maintained with halothane (expired concentration 1.0 per cent) in oxygen for three hours. During anaesthesia, arterial blood pressure, cardiac index, PaO2 and PmvO2 decreased, and systemic vascular resistance and PaCO2 increased. The cardiac indices for R80, R120 and D20 were, respectively, 39, 39 and 32 ml/kg/minute at 30 minutes and 29, 29 and 26 ml/kg/minute at 180 minutes. The alpha-2 agonists had similar cardiovascular effects, but PaO2 was significantly lower with R120. The quality of anaesthesia was similar in all three groups.     

Effect on pulse rate and blood pressure of premedication and epidural anaesthesia in the sow

Three groups of adult, healthy sows were given (i) azaperone 2 mg/kg intramuscularly (im), (ii) azaperone 2 mg/kg with atropine 0.02 mg/kg im, and (iii) azaperone 4 mg/kg im, while a fourth group was given epidural anaesthesia (lignocaine 2% with adrenaline) after premedication with azaperone 2 - 4mg/kg with or without atropine 0.02 mg/kg im. Pulse rate (P) and systolic (SBP), mean (MBP) and diastolic (DBP) arterial blood pressures were measured using an automatic oscillometric method. Systolic (SBP), mean (MBP) and diastolic (DBP) blood pressures were reduced to 65–70% of control values in all the first three premedication groups, but there was a marked individual variation; the larger azaperone dose seemed to give a faster decline, and atropine did not prevent the fall. Pulse rate (P) showed a transitory rise in the two groups not given atropine. There were no other significant differences between these three groups. Epidural anaesthesia had no significant additional effect on any of the parameters measured.     

Analgesia in Dogs After Intercostal Thoracotomy: A Clinical Trial Comparing Intravenous Buprenorphine and Interpleural Bupivacaine

We prospectively studied 26 dogs that presented for intercostal thoracotomy. Dogs were pre-medicated with oxymorphone, induced with diazepam and etomidate, and anesthesia was maintained with isoflurane in oxygen. Preoperatively, animal patients were randomly assigned to one of two groups. Group 1 (n = 13) received buprenorphine (10 μg/kg intravenously [IV]) every 6 hours for 24 hours starting 10 minutes before tracheal extubation. Group 2 (n = 13) received 0.5% bupivacaine (1.5 mg/kg) administered interpleural (IP) by slow injection through a pediatric feeding tube fixed to the most dorsal aspect of the thoracotomy incision. Interpleural injections were administered with each dog placed in lateral recumbency with the incision positioned ventrally; IP injections were administered every 4 hours for 24 hours starting 10 minutes before tracheal extubation. All cases were monitored in the intensive care unit for 24 hours postoper-atively. The analgesic efficacy of each regimen was evaluated using a pain scoring system that included a subjective pain score, heart rate, and respiratory rate. Arterial blood pressure, arterial blood gases, oxygen saturation, body temperature, and changes in the electrocardiogram or neurological status were also noted. Significant increases in mean heart rate, respiratory rate, and total pain score occurred after surgery in dogs in the buprenorphine group. In contrast, dogs in the bupivacaine group had no significant changes when compared with their preoperative values. Dogs in the bupivacaine group had significantly decreased total pain scores and better PaO₂ and oxygen saturation values when compared with the dogs receiving buprenorphine. Hypoventilation did not occur in either group.     

Anesthesia of bulls undergoing surgical manipulation of the vas deferentia.

Twelve bulls ranging from 341 to 545 kilograms in body mass were successfully anesthetized for either vasectomy or prosthetic vas deferens implantation with a combination of thiopental sodium, glyceryl guaiacolate, nitrous oxide, halothane and oxygen. Duration of anesthetic administration was 119.2 plus or minus 24.2 (S.D.) minutes. Righting reflexes returned 15.0 plus or minus 8.0 minutes after cessation of anesthetic administration and the bulls were capable of standing within 46.6 plus or minus 17.8 minutes. Interpretations of pulse rate, respiratory rate and eye reflexes were related to anesthetic depth and maintenance. A control mean respiratory frequency of 28.8 plus or minus 3.6 per minute compared to minimum and maximum frequencies of 26.8 plus or minus 5.1 and 37.6 plus or minus 6.3, respectively, during anesthetic maintenance. A control mean pulse frequency of 91.6 plus or minus 15.9 per minute compared to minimum and maximum frequencies of 84.8 plus or minus 13 and 102.3 plus or minus 13.4, respectively, during maintenance of anesthesia. Methods for avoiding complications related to anesthetic induction, maintenance and emergence were described. Specific pharmacological aspects of atropine, halothane and nitrous oxide were emphasized in light of their application to ruminant anesthesia.     

An improved microbiological procedure for detection of streptomycin residues in milk and animal tissues.

A method is described which allows detection of 0.025 µg streptomycin sulfate per ml. This represents an improvement of sensitivity by 8 times when compared with the currently used method. By adding penicillin to the assay medium in subinhibitory concentrations, a synergistic effect of streptomycin and penicillin is exerted towards the test organism, Bacillus subtilis, resulting in an increased sensitivity to streptomycin.     

Use of sedation and ropivacaine‐morphine epidural for femoral head and neck ostectomy in a dog

A five‐year‐old male German shepherd dog presented with traumatic craniodorsal luxation of the right coxofemoral joint with pre‐existing moderate hip dysplasia. A femoral head and neck ostectomy was performed. The patient was sedated with acepromazine and morphine administered intramuscularly. A lumbosacral epidural was performed using a combination of morphine and ropivacaine. Intraoperatively, an infusion of medetomidine, morphine, lidocaine, and ketamine was administered intravenously, and oxygen was administered via facemask. Heart rate, respiratory rate and oscillometric arterial blood pressures were monitored. Postoperatively, carprofen was administered once subcutaneously. On the day of hospital discharge, carprofen and tramadol were administered orally every 12 hours. Twenty‐one days later, the dog was doing well and the surgical staples were removed. Sedation with acepromazine and morphine, administration of an epidural containing morphine and ropivacaine, and intraoperative sedation with medetomidine, morphine, lidocaine and ketamine were suitable for femoral head and neck ostectomy .     

Thirteen-week dose-intensifying simultaneous combination chemotherapy protocol for malignant lymphoma in dogs

This prospective study aimed to record the toxicity profile of a dose-intensifying simultaneous chemotherapy (DISC) protocol for lymphoma in dogs. Remission rates and the duration of the protocol were also evaluated. Twenty-one dogs were studied. Diagnosis was based on cytological or histological assessments. The DISC protocol is a 13-week maintenance-free protocol. L-Asparaginase (400 iu/kg) was administered subcutaneously on day 1, followed by weekly simultaneous intravenous administration of vincristine (0.7 mg/m(2) = 100 per cent), cyclophosphamide (200 mg/m(2) = 100 per cent) and doxorubicin (30 mg/m(2) = 100 per cent) at a starting dose level of 33 per cent. Dose levels were given twice and then increased by 5 to 7 per cent if grade 0 or I toxicities were seen, to a maximum dose level of 60 per cent. Two dogs experienced a grade IV toxicity (asymptomatic neutropenia in one dog and sepsis in the other). Two episodes of asymptomatic grade III thrombocytopenia and one episode of neutropenia were recorded. Other toxic events were infrequent and mild. Only one dog required hospitalisation for less than 72 hours. Seventeen dogs (80.9 per cent) achieved complete remission, one (4.8 per cent) achieved partial remission, two (9.5 per cent) had stable disease and in one (4.8 per cent) disease progressed.     

Collection of bronchoalveolar lavage fluid in cats, using an endotracheal tube

Bronchoalveolar lavage fluid was collected from 12 anesthetized cats by use of an endotracheal tube and syringe adapter. The safety of the technique was evaluated by monitoring mucous membrane color, capillary refill time, pulse rate, respiratory rate, ECG, and arterial blood gas tensions and by necropsy findings. Group A consisted of 3 cats that were administered (by lavage) 4 aliquots of 20 ml of saline solution during anesthesia for placement of femoral artery catheters. Group B consisted of 4 cats that were administered a smaller total volume of saline solution (3 aliquots of 5 ml/kg of body weight) during a separate anesthetic period, other than the one for placement of catheters. Group C consisted of 5 cats administered 3 aliquots (5 ml/kg) of saline solution during a separate anesthetic period and administered supplemental oxygen for 5 to 10 minutes before and for 20 minutes after the lavage procedure. Group-A cats had a prolonged recovery period that was attributed to the lengthy anesthetic period required for placement of femoral catheters. The effect was eliminated in the cats of the other groups in which the lavage procedure itself accounted for only 5 to 10 minutes of anesthetic time. Evaluation of mucous membrane color, capillary refill time, ECG, pulse, and respiratory rate revealed no persistent abnormalities. Transient increase in pulse and respiratory rate was seen in some cats. Blood gas analysis revealed noticeable decrease in arterial oxygen pressures (Pao2) after the lavage procedure. In group-C cats, oxygen supplementation allowed the maintenance of normal or above normal Pao2.(ABSTRACT TRUNCATED AT 250 WORDS)