thiopental and alphaxalone

Alfaxalone, a synthetic neuroactive steroid, has been attributed with properties including sedation, anaesthesia and analgesia. The clinical relevance of any analgesic properties of alfaxalone has not been demonstrated. This study was a prospective, blinded, randomized, negative control clinical trial in 65 healthy dogs presented for ovariohysterectomy. Anaesthesia was induced and maintained, for Group 1 (TIVA) dogs (n = 30) with intravenous alfaxalone alone and for Group 2 dogs (n = 35) with thiopental followed by isoflurane in 100% oxygen inhalation. After ovariohysterectomy, quantitative measures of pain or nociception were recorded at 15 min intervals for 4 hr using three independent scoring systems, a composite measure pain scale (CMPS), von Frey threshold testing and measures of fentanyl rescue analgesia. The mean CMPS scores of Group 2 (THIO/ISO) dogs remained higher than Group 1 (TIVA) dogs from 15 to 135 min post-surgery but this difference was not statistically significant. There were no significant differences between groups in the proportions of dogs requiring rescue fentanyl analgesia, the total fentanyl dose used or the time to first fentanyl dose. The Von Frey threshold testing was found to be unsuitable for measurement of pain in this experimental model. When administered as total intravenous anaesthesia, alfaxalone did not provide analgesia in the postoperative period.

Topics: Anesthesia, Inhalation; Anesthesia, Intravenous; Anesthetics; Anesthetics, Combined; Anesthetics, Inhalation; Animals; Dogs; Female; Isoflurane; Male; Postoperative Care; Pregnanediones; Random Allocation; Thiopental

To compare the effect of chemical and mechanical stimulation on arytenoid cartilage motion during anaesthetic induction with alfaxalone, thiopentone or propofol.. Masked, randomized, crossover study.. A group of eight adult Beagle dogs.. Anaesthesia was induced with thiopentone (7.5 mg kg. The duration of examination time was shorter among treatments combined with chemical stimulation (p=0.001). Examination time during induction was longer for alfaxalone-chemical (8.9 minutes) and -mechanical (10.9 minutes) compared to both induction with thiopentone-chemical (3.8 minutes) and propofol-chemical (4.0 minutes). The median number of arytenoid motions for both thiopentone (67) and propofol (59) induction combined with chemical stimulation was significantly higher in comparison to that of alfaxalone (1), thiopentone (2) and propofol (2), when combined with mechanical stimulation at 3 minutes after induction.. Among the regimens for assessing laryngeal motion assessed in the present study, combinations of thiopentone or propofol with doxapram are the most effective means of stimulating arytenoid motion and could improve the accuracy of diagnosis of laryngeal paralysis in dogs.

Topics: Anesthesia; Anesthetics; Anesthetics, Intravenous; Animals; Cross-Over Studies; Dog Diseases; Dogs; Larynx; Pregnanediones; Propofol; Random Allocation; Thiopental; Vocal Cord Paralysis

To compare the effects of thiopentone, propofol and alfaxalone on arytenoid cartilage motion and establish the dose rates to achieve a consistent oral laryngoscopy examination.. Randomised crossover study.. Six healthy adult Beagle dogs.. Each dog was randomly administered three induction agents with a 1-week washout period between treatments. Thiopentone (7.5 mg kg. The median (range) induction and examination times were 2.8 (2.0-3.0), 2.7 (2.0-3.3) and 2.5 (1.7-3.3) minutes (p = 0.727); and 14.1 (8.0-41.8), 5.4 (3.3-14.8) and 8.5 (3.8-31.6) minutes (p = 0.016) for thiopentone, propofol and alfaxalone, respectively. The median dose rates required to achieve an adequate anaesthetic depth were 6.3 (6.0-6.6), 2.4 (2.4-2.4) and 1.2 (1.2-1.2) mg kg. The number of arytenoid motions were similar among the induction agents. However, at the dose rates used in this study, propofol provided adequate conditions for evaluation of the larynx with a shorter examination time which may be advantageous during laryngoscopy in dogs.

Topics: Animals; Arytenoid Cartilage; Cross-Over Studies; Dogs; Hypnotics and Sedatives; Laryngoscopy; Larynx; Movement; Pregnanediones; Propofol; Thiopental

In a double-blind study, 57 patients were anaesthetized with either Althesin, thiopentone, or fentanyl combined with diazepam for cystoscopies. One and a half and four hours after the administration of anaesthesia, the patients were investigated with an objective neuropsychological method, continuous Reaction Time, and with a subjective rating scale. Beecher's Mood Scale. One week later the patients answered a questionnaire about side-effects experienced during the days following anaesthesia. At the 1 1/2 h investigation, the patients were cerebrally affected, both subjectively and objectively. The CNS-dysfunction was different for the three anaesthetics. After administration of thiopentone, the patients experienced the highest degree of subjective effects but had the smallest reaction time prolongation. Fentanyl-diazepam gave the least subjective effects, but the highest degree of cerebral affection in the reaction time measurements. The effects of Althesin were intermediate. Four hours after anaesthesia, the reaction time prolongations had disappeared, except for Althesin, and only patients who had thiopentone registered subjective effects. The number of side-effects was greatest and most prolonged following thiopentone. About 25% of the patients reported that side-effects had persisted more than 1 day after anaesthesia.

Topics: Adult; Aged; Alfaxalone Alfadolone Mixture; Anesthetics; Clinical Trials as Topic; Cognition Disorders; Diazepam; Double-Blind Method; Female; Fentanyl; Humans; Male; Middle Aged; Mood Disorders; Postoperative Period; Pregnanediones; Thiopental

Topics: Anesthetics; Desflurane; Pregnanediones; Thiopental

Topics: Anesthesia, General; Anesthetics; Animals; Arytenoid Cartilage; Diazepam; Dogs; Drug Combinations; Laryngoscopy; Pregnanediones; Propofol; Thiopental; Video Recording

There is limited information on clinical use of the new injectable anaesthetic agent alfaxalone in Thoroughbred horses.. To compare anaesthetic induction and recovery characteristics and cardiopulmonary responses between alfaxalone, ketamine and thiopental in Thoroughbred horses premedicated with medetomidine and midazolam.. Randomised blinded experimental cross-over study.. Six Thoroughbred horses were anaesthetised 3 times with alfaxalone 1 mg/kg bwt, ketamine 2.5 mg/kg bwt or thiopental 4 mg/kg bwt after premedication with medetomidine 6 μg/kg bwt and midazolam 20 μg/kg bwt. Qualities of anaesthetic induction and recovery were scored on a scale of 1 (poor) to 5 (excellent). Induction time and recovery time were recorded. Cardiopulmonary values (heart rate, respiratory rate, arterial blood pressures, and arterial blood gases) were recorded throughout anaesthesia. Data were analysed with nonparametric methods.. The anaesthetic induction (P = 0.2) and recovery (P = 0.1) quality scores (median, range) were not different amongst protocols and were 4.0, 3-5; 5.0, 4-5; 4.5, 3-5; and 4.5, 3-5; 3.5, 2-5; 4.0, 2-5 for alfaxalone, ketamine and thiopental, respectively. Induction time for ketamine (67, 53-89 s) was significantly longer than that for alfaxalone (49, 40-51 s, P = 0.01) and thiopental (48, 43-50 s, P = 0.01). Time to standing for alfaxalone (44, 40-63 min, P = 0.01) and thiopental (39, 30-58 min, P = 0.01) was significantly longer than that for ketamine (25, 18-26 min). Cardiovascular values were maintained within the clinically acceptable level throughout anaesthesia. Respiratory rate significantly decreased during anaesthesia for all 3 drugs; however, spontaneous breathing did not disappear, and PaCO. All 3 drugs showed similar effects in relation to anaesthetic induction and recovery qualities and cardiopulmonary responses. However, alfaxalone and thiopental prolonged recovery time compared with ketamine.

Topics: Anesthetics; Animals; Drug Therapy, Combination; Horses; Hypnotics and Sedatives; Ketamine; Medetomidine; Midazolam; Pregnanediones; Premedication; Thiopental

To compare the growth of Staphylococcus aureus and Escherichia coli in alfaxalone with that in propofol and thiopental and to evaluate contaminant microbial growth in these agents under two different conditions of storage and handling.. Known quanta of S aureus and E coli were inoculated into separate 5 ml samples of propofol, thiopental and alfaxalone. Quantitative bacterial analysis was performed at intervals over a 14 day period. Commercial preparations of propofol, thiopental and alfaxalone were stored and handled using "dirty" or "clean" techniques. Microbial quantification and identification was performed over a 14 day period.. S aureus and E coli grew rapidly in propofol after six hours. Both bacteria were killed by thiopental. S aureus numbers slowly declined in alfaxalone; E coli growth was rapid after 24 hours. In "dirty" and "clean" groups of intravenous anaesthetics, 9.3 and 7.4 per cent of samples, respectively, were positive for microbial growth; none were considered to represent colonisation of bottles.. Alfaxalone supports growth of some microorganisms but less readily than propofol. Bacterial colonisation of intravenous anaesthetic bottles is uncommon, but contamination as syringes are prepared for injection occurs regardless of storage and handling technique.

Topics: Anesthetics; Anesthetics, Intravenous; Colony Count, Microbial; Dose-Response Relationship, Drug; Drug Combinations; Escherichia coli; Kinetics; Microbial Sensitivity Tests; Pregnanediones; Propofol; Specimen Handling; Staphylococcus aureus; Thiopental; Treatment Outcome

Prolonged, stable, non-recovery anaesthesia is required for the assessment of the effects of novel compounds on the cardiovascular system. A comparison of injectable anaesthetic agents and combinations (thiobarbital, fentanyl-fluanisone and midazolam, propofol, fentanyl-fluanisone and propofol, and alphaxalone/alphadolone) was made in laboratory rats and the following parameters assessed over 3 h: blood pressure, heart rate and rhythm, respiration rate and depth, analgesia, ease of induction and maintenance of anaesthesia. It was found that propofol, with fentanyl-fluanisone premedication, provided stress-free induction, easily controlled anaesthesia, good analgesia and muscle relaxation for surgery, for up to 3 h duration. Heart rate, blood pressure and respiration remained stable and within normal limits during this time. The other anaesthetics/combinations assessed did not rate as highly in these respects. Propofol, following fentanyl-fluanisone premedication, would appear to be a useful and safe anaesthetic for use in rodents, which avoids significant effects on heart rate or blood pressure.

Topics: Anesthesia, Intravenous; Anesthetics; Animals; Blood Pressure; Butyrophenones; Female; Fentanyl; Heart Rate; Male; Midazolam; Pentobarbital; Pregnanediones; Propofol; Rats; Respiration; Thiopental

The anaesthetic induction agents thiopentone, propofol and alphaxalone-alphadolone were administered to cats intravenously and ketamine and xylazine-ketamine-atropine were administered intramuscularly in order to determine their effects on gastric pressure, lower oesophageal sphincter pressure, and barrier pressure. Manometric measurements were made with a non-perfused catheter tip pressure transducer. All the anaesthetic induction agents decreased the tone of the lower oesophageal sphincter but the reduction was least with ketamine. Lower oesophageal sphincter tone was significantly higher in cats anaesthetised with either xylazine-ketamine-atropine or propofol than in cats anaesthetised with either thiopentone or alphaxalone-alphadolone. Despite a higher gastric pressure in the cats anaesthetised with ketamine rather than with the other drugs except propofol, the barrier pressure was also significantly higher in cats anaesthetised with ketamine than in cats anaesthetised with any of the other drugs except xylazine-ketamine-atropine. The risk of gastrooesophageal reflux seemed to be higher with alphaxalone-alphadolone than with thiopentone if the lower oesophageal sphincter pressure and gastric pressure are used as indicators of likely reflux.

Topics: Anesthetics; Animals; Cats; Esophagogastric Junction; Female; Ketamine; Male; Pregnanediones; Pressure; Propofol; Random Allocation; Stomach; Thiopental; Xylazine

Testosterone and androstenedione were measured in the plasma of mature tom-cats before, during and after anesthesia with thiopentone, ketamine, xylazine and alphaxolone/alphadolone. Samples were collected via an indwelling jugular catheter at 30 min intervals before anesthesia (5 samples) and during the recovery phase (8 samples), and at intervals of 15 min during anesthesia (7 samples). Thiopentone and ketamine anesthesia significantly depressed testosterone and androstenedione concentrations during and after anesthesia. Xylazine significantly increased testosterone concentrations during anesthesia but they returned to pre-anesthetic concentrations during recovery. Androstenedione concentrations were significantly depressed during the recovery phase from xylazine anesthesia. Alphaxolone/alphadolone anesthesia had no significant effect of testosterone concentrations but significantly increased and androstenedione concentrations during anesthesia and recovery. Testosterone and androstenedione concentrations in cats were significantly altered by these 4 commonly used anesthetics and this must be taken into account if hormone concentrations are measured while cats are anesthetised.

Topics: Androstenedione; Anesthesia, Intravenous; Anesthetics; Animals; Animals, Domestic; Cats; Ketamine; Male; Pregnanediones; Testosterone; Thiopental; Time Factors; Xylazine

Topics: Adolescent; Anesthetics; Brain; Brain Injuries; Coma; Drug Therapy, Combination; Electroencephalography; Humans; Intracranial Pressure; Male; Monitoring, Physiologic; Pregnanediones; Thiopental

A group of intravenous anaesthetic drugs was compared with methohexitone sodium for their ability to potentiate tetraethylammonium induced contractures of the chick biventer cervicis muscle (TEA test). The equipotent concentrations in the TEA test were: methohexitone 8.8 X 10(-5) M, propanidid 1.78 X 10(-4) M, althesin 3.58 X 10(-5) M (in terms of alphaxalone), etomidate 1.6 X 10(-4) M, thiopentone 2.13 X 10(-5) M and valium 4.95 X 10(-5) M. There was no relation between activity in the TEA test and excitatory muscular activity reported clinically. The central depressant drugs ethyl alcohol and urethane also potentiated TEA but they were only active in high concentrations (10(-1) - 10(-2) M). alpha-Chloralose was inactive but paraldehyde (3.8 X 10(-3) M) actually reduced TEA induced contractures. Lipophilicity is only one factor in determining activity in the TEA test, the ability to block Ca2+ reuptake may also be important.

Topics: Alfaxalone Alfadolone Mixture; Anesthetics; Animals; Central Nervous System Depressants; Chickens; Chloralose; Diazepam; Drug Synergism; Ethanol; Etomidate; In Vitro Techniques; Methohexital; Muscle Contraction; Neck Muscles; Paraldehyde; Pregnanediones; Propanidid; Tetraethylammonium; Tetraethylammonium Compounds; Thiopental; Urethane

The selective actions of intravenous anesthetics on the cholinergic nicotinic and muscarinic responses of adrenal medullary cells were studied using isolated dog adrenals perfused with modified Locke's solution. Log-probit dose-response curves of the inhibitory effects of the anesthetics on the catecholamine releases induced by acetylcholine, nicotine, and muscarine were determined. Percentage inhibition by the anesthetics at clinically relevant concentrations were 98% of nicotine- and 31% of muscarine-induced releases by alphaxalone 2.6 microM, 76% of nicotine and 13% of muscarine by thiopental 23.9 microM, 86% of nicotine and no inhibition of muscarine by ketamine 17.0 microM, and no inhibition of either response by diazepam 5.0 microM. The ratio of IC50 (concentration for 50% inhibition), which was calculated by dividing IC50 for muscarine by IC50 for nicotine, showed a variety of values ranging from 3.9 for diazepam to 38.0 for ketamine. The results suggest that each anesthetic has characteristic selective inhibitory effects on nicotinic and muscarinic cholinergic responses. The differing effects on the muscarinic responses might be one of the factors contributing to the characteristic properties of each anesthetic, whereas the inhibition of nicotinic responses might reflect a common property for many anesthetics.

Topics: Adrenal Medulla; Anesthetics; Animals; Catecholamines; Diazepam; Dogs; In Vitro Techniques; Ketamine; Pregnanediones; Receptors, Muscarinic; Receptors, Nicotinic; Thiopental

Topics: Anesthetics; Animals; Blood Pressure; Carbon Dioxide; Cats; Heart Rate; Ketamine; Oxygen; Pregnanediones; Respiration; Thiopental

Repeated bolus doses of thiopentone or Althesin were administered to 10 patients every 240 s while cerebral electrical activity was recorded with the Cerebral Function Monitor (CFM). Peripheral venous blood samples were collected at 60 and 225 s after each bolus dose for the measurement of plasma concentrations of the drugs. Significant correlations in the range r = 0.56-0.96 (P = 0.02-0.00001) between plasma thiopentone or alphaxalone concentrations and the upper and lower edges of the CFM trace were found. For the patients with relatively poor correlations, better correlations were obtained when 60- and 225-s sample were analysed separately.

Topics: Alfaxalone Alfadolone Mixture; Anesthesia, Intravenous; Anesthetics; Cerebral Cortex; Drug Administration Schedule; Electroencephalography; Female; Humans; Pregnanediones; Thiopental