Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    ISSN: 1432-1041
    Keywords: thiopentone ; anaesthesia ; intravenous anaesthesia ; multi-stage infusion ; exponential infusions ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Several multi-stage infusion regimens and a computer controlled exponentially decreasing infusion regimen were evaluated in twelve patients undergoing head and neck surgery or neurosurgery. Thiopentone dosage was based on the mean of pharmacokinetic parameter values from the literature and adjusted for each patient's lean body mass in order to rapidly achieve a predetermined plasma thiopentone concentration of 15 or 20 µg/ml in the period following the initial bolus dose to induce anaesthesia. Anaesthesia was satisfactory in all cases. Plasma thiopentone concentrations were maintained between 10–20 µg/ml during infusion in the five patients who received either a four or five stage infusion and in the six patients who received the exponential infusion, but not in the single patient who received a two-stage infusion. The mean recovery time was 111 min. The plasma concentrations of total and unbound thiopentone at awakening showed little intersubject variability, despite considerable differences in total dose and duration of infusion, suggesting the absence of acute tolerance to the drug. Plasma clearance of total thiopentone correlated strongly with calculated lean body mass and to a lesser extent with total body weight suggesting that lean body mass, in particular, should be an accurate predictor of thiopentone maintenance dose requirements. This study shows that it is feasible to use thiopentone as a primary anaesthetic agent during surgery by administering the drug either as an exponentially decreasing infusion or as an infusion comprising 4 or 5 stepwise decreasing rates.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 2
    ISSN: 1432-1041
    Keywords: Etidocaine ; epidural ; total blood clearance ; metabolism ; plasma protein binding ; placental transfer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Following epidural administration of etidocaine hydrochloride to non-pregnant and pregnant patients, a similar rate of absorption was observed and there was no significant difference in total systemic blood clearance (Clsb) of etidocaine in the two groups. There were no major differences in the urinary excretion of etidocaine and metabolites in 48 h urine in both groups. The ability of pregnant women to form the N-glucuronide of the metabolite ABX (2-amino-2′-butyroxylidide) was similar to that of non-pregnant individuals. In vitro experiments showed that the blood/plasma concentration ratio (λ) of etidocaine was significantly higher in pregnant females than in males, presumably due to the lower haematocrit in females. The fraction unbound in plasma (fp) of etidocaine was low in control subjects (mean 0.057) and was not significantly different in pregnant women of 35 to 37 weeks gestation. A marked increase in fp was observed in pregnant women during delivery (mean 0.264). This finding has potentially serious clinical implications because it is the unbound drug in blood which is pharmacologically important. Placental transfer of etidocaine was rapid and the cord/maternal venous blood concentration ratio at delivery (CMb) was, with one exception, always less than unity (mean 0.342). Following epidural administration of etidocaine to pregnant women in labour, measurable concentrations of mono-dealkylated metabolites of etidocaine, PABX (2-N-propylamino-2′-butyroxylidide) and EABX (2-N-ethylamino-2′-butyroxylidide) were detectable in maternal blood within 5 min and cord blood within 30 min. The CMb for PABX and EABX was 0.401 and 0.658 respectively.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 3
    ISSN: 1432-1041
    Keywords: etidocaine ; protein binding ; pregnancy ; alpha1-acid glycoprotein ; labour ; free fatty acids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Preliminary studies of the ultrafiltration method for measuring the extent of plasma protein binding of etidocaine showed that etidocaine binding was both pH and concentration dependent. Etidocaine (1 µg/ml) was found to bind avidly to a physiological concentration (74 mg/dl) of α1-acid glycoprotein (α1-AGP) (7.23±0.64%, mean ± SD, unbound). In vitro investigation of etidocaine binding in plasma obtained from blood bank donors and from 19 pregnant women prior to induction of labour, during early labour, mid-labour and delivery showed no difference in etidocaine binding (10.3±3.3%, 7.06±2.66%, 8.15±2.57%, 7.84±3.74% and 9.28±6.06% unbound respectively). There was a significant increase in the mean plasma total free fatty acid (FFA) concentration from pre-labour (0.535±0.240 mM) to delivery (0.948±0.28 mM), while plasma albumin and β-lipoprotein concentrations remained constant. α1-Acid glycoprotein concentration tended to increase slightly from pre-labour to early labour (p〈0.1) but was still within the normal physiological range. There was no correlation between etidocaine binding ratio and the concentrations of FFA or plasma proteins except for a poor correlation with the α1-AGP concentration (r=0.361, p〈0.05). Storage of plasma and inadequate control of plasma pH during ultrafiltration appeared to give spurious binding values. These studies with the extensively bound basic drug etidocaine suggest that unlike many acidic drugs which are bound predominantly to serum albumin, the binding of α1-AGP — bound basic drugs may be unaffected by pregnancy and labour.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 4
    ISSN: 1432-1041
    Keywords: cimetidine ; intravenous infusion ; pharmacokinetics ; peptic ulcer ; duration of infusion ; acute dose
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The use of cimetidine administered by bolus intravenous injection to critically ill patients has been associated with serious cardiac arrhythmias, due presumably to high initial plasma concentrations. The aim of this study was to determine the range of infusion times of a single 200 mg dose of cimetidine which would avoid high initial drug concentrations while maintaining a duration of effective concentrations no less than that resulting from bolus injection. Computer simulations of both maximum plasma cimetidine concentrations and duration of effective plasma cimetidine concentrations versus duration of infusion were based on mean pharmacokinetic date from 6 peptic ulcer patients who had received cimetidine 200 mg i.v. over 5 min. The simulations indicated that to reduce maximum plasma cimetidine concentrations by at least 50%, while maintaining the duration of effective plasma concentrations, the infusion time should be at least 30 min and no longer than 4.5 h. The validity of the simulations was subsequently tested in 4 of the patients, who received cimetidine 200 mg i.v. over 30 min. The mean maximum plasma concentration for the 30 min infusion (4.57±0.53 µg/ml) was, as predicted, approximately half that corresponding to bolus administration in these patients (8.97±1.96 µg/ml). Moreover, the duration of effective concentrations for the infusion (1.43±0.28 h) was significantly greater than that for the 5 min infusion (1.21±0.31 h). We suggest that where an acute intravenous dose of cimetidine (200 mg) is indicated, it should be administered over at least 30 min rather than as a bolus.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 5
    ISSN: 1432-1041
    Keywords: alfentanil ; plasma protein binding ; cardiopulmonary bypass ; intravenous infusion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The effect of cardiopulmonary bypass (CPB) on plasma concentration and protein binding of alfentanil was studied during continuous infusions in five cardiac surgical patients. Patients were given a loading infusion of 10 µg·min−1·kg−1 lean body mass (LBM) over 30 s followed by a fixed rate maintenance infusion of 1 µg·min−1·kg−1 LBM for the duration of surgery. Prior to the commencement of CPB the total plasma alfentanil concentration was 177 µg·l−1. This fell to 92 µg·l−1 2 min after commencement of CPB and rose to 155 µg·l−1 at the end of CPB 2.01 h later. During the same period the unbound fraction of alfentanil rose from 0.16 to 0.35 two min after the start of CPB and fell gradually to 0.22 at the end of CPB. The unbound concentration prior to CPB was 29 µg·l−1 and was essentially unchanged by the onset of CPB, being 35 µg·l−1 at two min and then 31 µg·l−1 at the end of CPB. There was a good correlation between alfentanil bound/unbound concentration ratio and plasma albumin concentration (r=0.57) and plasma α1-acid glycoprotein concentration (r=0.80), indicating that the decrease in binding during CPB was due primarily to haemodilution. In assessing the effects of CPB on plasma drug concentrations, it is therefore necessary to monitor unbound as well as total concentrations because the effects on these differ greatly.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 6
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 286 (1980), S. 248-249 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Fig. 1 CO2 evolution profiles obtained from: a, 0.2%; b, 500 p.p.m.; and c, 50 p.p.m. nominal concentrations of carbonate minerals in alumina. Evolution profiles in a and b were obtained using a carrier gas flow rate of 300 ml min"1 and in c with a flow rate of 100 ml min"1. Fig. 2 Plot of ...
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 7
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 218 (1968), S. 1177-1178 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] A study of the urinary excretion of iodide after inhalation of labelled ethyl iodide was also carried out on the same subject during a period of 4-5 h. As shown in Fig. 1, excretion of the labelled inorganic iodide occurred at a somewhat slower rate than after he had inhaled methyl iodide. It is ...
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 8
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 207 (1965), S. 1310-1311 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] In the present investigation an apparatus has been designed for the accurate determination of percentage retention of radioactive vapours when inhaled by human subjects. The first compound chosen for investigation was methyl iodide, which is of interest because it could constitute the major hazard ...
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 9
    Electronic Resource
    Electronic Resource
    [S.l.] : International Union of Crystallography (IUCr)
    Acta crystallographica 32 (1976), S. 926-926 
    ISSN: 1600-5724
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 10
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    The @journal of organic chemistry 27 (1962), S. 4646-4649 
    ISSN: 1520-6904
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...