PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “THIOPENTAL”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 recordsLinked to original sources
PubMed1996

Pharmacokinetics of thiopental and pentobarbital enantiomers after intravenous administration of racemic thiopental.

We studied the pharmacokinetics of thiopental enantiomers in 14 healthy patients aged 37-73 yr receiving racemic thiopental by intravenous (IV) bolus or IV infusion. Plasma concentration of each enantiomer was measured by chiral high-performance liquid chromatography. After IV bolus, the total plasma clearance (CL) (295 +/- 132 mL/min) and volume of distribution at steady state (Vss) (139 +/- 38.5 L) of R-thiopental were significantly greater than those of S-thiopental (230 +/- 104 mL/min and 114 +/- 47.5 L, respectively). The plasma unbound fraction (fu) was determined by ultrafiltration of plasma from six healthy volunteers. The fu of R-thiopental (12.4% +/- 0.6%) was significantly greater than that of S-thiopental (10.0% +/- 1.0%). When the CL and Vss of the two enantiomers were corrected for the difference in mean fu, there were no significant differences between enantiomers for these variables. As the 20%-30% difference between the enantiomers in total CL and total Vss could be accounted for by stereoselectivity in fu, these differences are not likely to be clinically significant. During 105-180 min IV infusion of racemic thiopental to the other patients, there was no difference between enantiomers in mean plasma concentrations of total or unbound thiopental or total pentobarbital, a major metabolite of thiopental (P > 0.05). Therefore, it is appropriate to relate pharmacodynamic effects to racemic plasma concentrations of thiopental during IV infusion of racemic thiopental.

Adult↗
PubMed1987

Toxicological study on intravenous thiopental anesthesia--interrelation between rate of injection and distribution of thiopental.

A simple, rapid and accurate method to extract and clean thiopental in biological materials rich in fat was developed by using a separation column packed with Extrelut and Florisil. A Quantitative determination of thiopental by means of a gas chromatograph equipped with a flame photometric sulfur detector was attempted. The calibration curve was linear over the range of 5-200 micrograms/ml. Extraction of replicate tissues involving 3 micrograms of thiopental resulted in a recovery of the 99.7-101.8% range and a coefficient of deviation of the 0.3-1.9% range. Replicate extraction of five tissues from rats treated with thiopental resulted in a coefficient of deviation of below 6%. In rats given 40 mg/kg of thiopental and sacrificed after 5 min, the thiopental levels in fat were found to be higher after a slow intravenous injection than after a quick injection. The same tendency, however, was not observed in other tissues. It seems that the rate of intravenous thiopental injections might be estimated by comparison with thiopental levels in fat tissues.

Anesthesia, Intravenous↗
PubMed1996

Growth of microorganisms in propofol, thiopental, and a 1:1 mixture of propofol and thiopental.

To assess and compare the growth of four microorganisms in solutions of intravenous anesthetics, known quanta of Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and Candida albicans were inoculated into propofol, thiopental, a 1:1 mixture of propofol and thiopental, and normal saline. All microorganisms were taken from standard stock cultures and incubated for 24 h (48 h for C. albicans). Growth of microorganism in each drug was compared by counting the number of colony forming units (CFUs) grown from a subculture of each inoculated anesthetic at 0, 3, 6, 12, and 24 h. The study shows that propofol strongly supports the growth of E. coli and C. albicans but is bacteriostatic toward S. aureus and weakly bactericidal toward P. aeruginosa. In contrast, both thiopental and the 1:1 mixture of propofol and thiopental behaved differently, exhibiting markedly bactericidal properties toward E. coli, S. aureus, and P. aeruginosa and a bacteriostatic effect on C. albicans. This finding supports recommendations that a strict aseptic technique should be used when handling propofol and that the contents of an ampoule should be used within 6 h of aspirating. The measured high pH of both thiopental and the 1:1 mixture of propofol and thiopental compared to propofol alone suggests pH to be a major factor in determining whether a given drug will support microbial growth.

Anesthetics, Intravenous↗
PubMed1986

Wakefulness during cesarean section after anesthetic induction with ketamine, thiopental, or ketamine and thiopental combined.

Thirty-six pregnant women (ASA class I or II) at term who underwent general anesthesia and cesarean section received either ketamine, 1 mg/kg (n = 12); thiopental, 4 mg/kg (n = 13); or a combination of ketamine, 0.5 mg/kg, and thiopental, 2 mg/kg (n = 11). A blood pressure cuff inflated to 250 mm Hg isolated one arm from the effects of succinylcholine so that awareness during anesthesia could be assessed by asking the patient to move her hand. Although only one patient receiving ketamine responded to commands during anesthesia, 46% of patients receiving either thiopental or the combination responded to commands intraoperatively. No patient hallucinated, the incidence of dreams was low (11%), and no postoperative dysphoria was noted. Three patients (8%) had postoperative recall of intraoperative awareness; one had received thiopental and two the combination. Maternal intraoperative cardiovascular responses among the groups were similar, as were umbilical blood gas values, newborn Apgar scores, and neonatal neurobehavioral test scores at 4 and 24 hr. Ketamine more effectively blocked maternal responsiveness to commands and strong stimuli during the first few minutes after anesthetic induction for cesarean section than did thiopental or a combination of thiopental and ketamine, each at a lower dose.

Adult↗
PubMed1993

Reinduction of the hypnotic effects of thiopental with NSAIDs by decreasing thiopental plasma protein binding in humans.

The effects of 14 non-steroidal anti-inflammatory drugs (NSAIDs)--naproxen, ibuprofen, mefenamic acid, ketoprofen, indomethacin, fenoprofen, diclofenac sodium, aspirin, salicylic acid, piroxicam, sulindac, fenbufen, flurbiprofen and benzydamine, on the plasma protein binding of thiopental and the clinical consequences of such interactions were studied. Four of them, naproxen, ibuprofen, salicylic acid and aspirin, very significantly decreased the protein binding of thiopental in vitro in human plasma (P < 0.005). Structurally, they were salicylates and propionic acid derivatives among the six classes of NSAIDs studied. The aspirin study demonstrated that the protein-displacing phenomenon was temperature-dependent, and concentration-dependent. Clinically, aspirin administered intravenously resulted in a significant increase in the percentage of plasma free thiopental from 16.01 +/- 3.59% to 22.27 +/- 3.96% (P < 0.001, n = 10) in patients undergoing surgery, and resulted in three of seven patients sleeping again during recovery from thiopental-induced anesthesia. Although the effect of chronic use of NSAIDs before anesthesia is uncertain, studies should be carried out to find out if naproxen, ibuprofen, and aspirin influence the depth of anesthesia, time of recovery and duration of action of thiopental.

Adult↗
PubMedDate not supplied

Hemodynamic stability and patient satisfaction after anesthetic induction with thiopental sodium, ketamine, thiopental-fentanyl, and ketamine-fentanyl.

STUDY OBJECTIVE: To examine three commonly used anesthetic induction regimens (thiopental sodium, ketamine, and thiopental plus fentanyl) and one newly described regimen (ketamine plus fentanyl) with respect to hemodynamic stability and patient satisfaction. DESIGN: Randomized, double-blind study. SETTING: University-affiliated Veterans Administration Hospital. PATIENTS: Forty-eight ASA physical status I and II patients (47 males, 1 female) scheduled for surgery requiring general anesthesia. INTERVENTIONS: Patients were randomized to one of four groups to receive intravenous injections of thiopental 5 mg/kg (Group 1), ketamine 1.5 mg/kg (Group 2), thiopental 3 mg/kg plus fentanyl 4 to 6 micrograms/kg (Group 3), or ketamine 0.5 mg/kg plus fentanyl 4 to 6 micrograms/kg (Group 4) for induction of anesthesia. MEASUREMENTS AND MAIN RESULTS: Heart rate (HR) and mean arterial pressure (MAP) were measured during anesthetic induction. Evaluation of patient satisfaction/dissatisfaction and pleasantness/unpleasantness by the Anesthesia Experience Rating (AER) was carried out the day following surgery. Groups 3 and 4 showed the least increase from their baseline values in both HR and MAP after tracheal intubation, but only Group 4 exhibited no statistically significant change in hemodynamic parameters after induction but before intubation (p < 0.05). AER showed a higher level of pleasantness in Group 3 as compared with Group 2 (p < 0.03) and higher levels of satisfaction in Groups 3 (p < 0.03) and 4 (p < 0.02) as compared with Group 2. CONCLUSION: The combination of ketamine plus fentanyl provides superior hemodynamic stability with excellent patient satisfaction.

Anesthesia, Intravenous↗
PubMedDate not supplied

[The influence of modulators of enzyme activity on the pharmacological effect of thiopental sodium and ketamine and on the pharmacokinetics of thiopental sodium].

The rat experiments studied the impact of inductors and inhibitors of enzymatic activity of xenobiotic metabolism on the pharmacological activity of sodium thiopental and ketamine and on the pharmacokinetics of sodium thiopental. Cocarboxylase, cobalt chloride and cimetidine enhanced the pharmacological action of sodium thiopental, but failed to exert any action on the effect of ketamine. The preparations of vitamin K, particularly vikasol and menadione sodium bisulfite, and phenobarbital attenuated the effects of these anesthetics, but tocopherol unchanged it. Phenobarbital and vikasol accelerated blood elimination of sodium thiopental, whereas cimetidine and cocarboxylase slowed down this process.

Animals↗
PubMed1996

Myocardial pharmacokinetics of thiopental in sheep after short-term administration: relationship to thiopental-induced reductions in myocardial contractility.

The myocardial kinetics and dynamics of thiopental (750 mg over 2 min) were examined in chronically instrumented sheep (five studies in four sheep). The myocardial kinetics were studied by simultaneous rapid sampling of arterial and coronary sinus blood for 30 min. The myocardial kinetics for four of the five studies were best described by a single flow-limited compartment with apparent volumes of between 42 and 113 mL. These volumes equated to half-lives of equilibration between blood and myocardium of between 0.49 and 1.00 min when baseline blood flow was taken into account. The remaining study was better described by a model with a slight membrane limitation (permeability/flow ratio of approximately 2). Myocardial contractility was studied as a measure of myocardial pharmacodynamics and was reduced to 53% of baseline at approximately 2.5 min after the start of the dose. Effect compartment analysis showed that there was hysteresis between the time course of these contractility changes and the time course of the arterial concentrations, with effect compartment half-lives between 0.08 and 0.87 min. There was significantly less hysteresis for the coronary sinus concentrations. It is concluded that thiopental equilibrated rapidly with a component of the myocardium, and that consequently its effects on myocardial contractillity also rapidly equilibrated with both afferent and effluent myocardial blood.

Animals↗
PubMed1988

[Cardiorespirographic parameters in the first 12 hours of life. Influence of the administration of thiopental and diazepam plus thiopental on labor].

Cardiorespirographic parameters undergo a series of evolutionary modifications during first hours of life, becoming stable between the sixth and twelfth. The authors analyse how these parameters are influenced by the administration to the mother of thiopental and diazepam plus thiopental during birth. They observed a significant reduction, during the first hour after birth, in the range and frequency of accelerations in the newborn babies whose mothers had been administered one of the drugs. Also, they observed a greater number of cases of decelerations in the newborns who were given drugs. No significant differences were observed in other parameters, and after the twelfth hour no differences were observed at all.

Diazepam↗
PubMed1987

[Serum thiopental values, spontaneous frontal muscle electromyography activity and compressed EEG amplitudes and frequency values in thiopental infusion anesthesia].

Serum thiopentone (S-Thiop) was estimated every 10 minutes using a new high performance liquid chromatographic method during fentanyl-bolus-complemented (0.01 mg) thiopentone infusion anaesthesia (bolus of 5 mg/kg, infusion dosis 23.7 mg/min) for laryngo-microscopic procedures. Before stopping the infusion after 18/17 min (SD 8/5) (male/female) S-Thiop was (mean (SD) range) 16.0/12.4 (4.6/5.7) 5.9-26.8/5.1-26.6 mg/l; after stop of the infusion 12.8/10.5 (4.5/5.3) 7.6-25.5/4.5-23.4 mg/l. Patients reacted to verbal command after 11.5 (10.3) 11-81 min. There were no clinically relevant correlations between S-Thiop and frontal EMG and compressed 1-channel-EEG (ABM, Datex, Helsinki), nor with data recorded during recovery. Reasons may be: the total depolarisation block caused by succinylcholine; the method of compressing the EEG; subjective influences on the recording of recovery data; sampling in intervals of 10 min instead of at certain points of the anaesthesia course. We still recommend this total i.v.-anaesthesia for the short time endolaryngeal procedures need; before using this method for longer periods additional pharmacokinetic studies should be performed.

Adult↗
PubMed1999

Enantioselectivity of thiopental distribution into the central neural tissue of rats: an interaction with halothane.

UNLABELLED: Thiopental is a racemate. In this study, we examined whether thiopental total body clearance and its distribution into central nervous system (CNS) tissue of rats was enantioselective. Rats, either anesthetized with halothane or conscious and restrained, were infused to stepwise steady-state targets of 5, 10, and 20 microg/mL thiopental by computer-controlled infusions. Serial arterial plasma and steady-state samples of brain and spinal cord were assayed enantiospecifically for thiopental. In both groups, concurrent total and unbound plasma concentrations of S-thiopental were approximately 10%-20% higher than those of R-thiopental, corresponding to its higher clearance. CNS tissue concentrations of S-thiopental were approximately 20% higher than those of R-thiopental. Spinal cord to plasma distribution coefficients were approximately 2 x those in the brain, with relative distribution coefficients approximately 10% greater for R-thiopental in both tissues. Plasma concentrations and distribution coefficients of both enantiomers were approximately 10%-20% lower in the halothane-anesthetized group, with a slightly greater effect on R-thiopental distribution. We conclude that the total body clearance of R-thiopental > S-thiopental, that halothane enantioselectively reduces the relative uptake of R-thiopental into brain tissue, and that composition is important in determining the CNS tissue concentrations of thiopental. The reported higher potency of S-thiopental did not seem to be due to its greater distribution into CNS tissues. IMPLICATIONS: Because thiopental is a mixture of two forms (termed R-and S-enantiomers), correct interpretation of its distribution into, and clearance from, the body requires knowledge about both enantiomers. In this study, performed in rats, we showed that the two enantiomers of thiopental differed significantly, with the R-enantiomer having the preferred profile.

Anesthetics, Inhalation↗
PubMed1989

Myocardial sensitization by thiopental to arrhythmogenic action of epinephrine in dogs.

This study examined the interaction between thiopental and epinephrine in inducing ventricular arrhythmias in dogs. The arrhythmogenic threshold of epinephrine was determined during anesthesia with either halothane alone, thiopental alone, etomidate plus different doses of thiopental, or halothane plus different doses of thiopental. The arrhythmogenic dose and the corresponding plasma concentration of epinephrine during thiopental anesthesia (plasma thiopental concentration: 46-57 micrograms/ml) were 0.77 +/- 0.04 micrograms.kg-1.min-1 and 10.7 +/- 1.5 ng/ml, respectively. During halothane anesthesia (end-tidal: 1.3 MAC) they were 2.59 +/- 0.49 micrograms.kg-1.min-1 and 45.3 +/- 9.2 ng/ml, respectively. The dose-effect relationship for the thiopental action was examined during etomidate plus thiopental and halothane plus thiopental anesthesia. The arrhythmogenic plasma concentration of epinephrine was inversely proportional to the plasma thiopental concentration during both anesthetics. During etomidate plus thiopental anesthesia, at plasma thiopental concentrations of 0, 11.2 +/- 0.83, 20.1 +/- 1.34, and 33.2 +/- 1.95 micrograms/ml, the corresponding epinephrine concentrations were 201.3 +/- 34.3, 142 +/- 19.5, 69.1 +/- 21.2, and 22.7 +/- 4.5 ng/ml. During halothane plus thiopental anesthesia, at plasma thiopental concentrations of 0, 10 +/- 0.86, 18.3 +/- 0.87, and 31.8 +/- 1.05 micrograms/ml, the corresponding epinephrine concentrations were 45.3 +/- 9.2, 34.6 +/- 8.9, 16.2 +/- 1.74, and 15.1 +/- 1.32 micrograms/ml, respectively. These results suggest that thiopental sensitizes the heart to epinephrine in a dose-dependent manner. This sensitizing action of thiopental would in part explain the thiopental potentiation of hydrocarbon anesthetic-epinephrine arrhythmias.

Anesthetics↗