PubMed Health⌕ Search

Biomedical subjects

H Choisy

Publications and source records attributed to H Choisy.

At least 19 recordsLinked to original sources
PubMed1995

Imputability of heparin in heparin induced thrombocytopenia: a 10 year experience of the Centre Regional de Pharmacovigilance of Reims-Champagne Ardenne.

The imputability of heparin in heparin induced thrombocytopenia (HIT) was analysed retrospectively in the chart records of 86 cases documented by the Centre Regional de Pharmacovigilance (CRPV) of Reims-Champagne Ardenne over a period of 10 years. Considerable difficulties are encountered in evaluating the degree of imputability. Chronological criteria seem to be determinant in the final imputability score, whereas semiological criteria are particularly difficult to interpret, especially as it is not yet clearly established whether biological tests should be taken into account. The method of assessment requires more precise adaptation to the specific case of HIT and could be improved by redefinition of the criteria in collaboration between pharmacologists and haematologists.

Adult↗
PubMed1994

Comparative pharmacokinetics of two diastereoisomers dexamethasone and betamethasone in plasma and cerebrospinal fluid in rabbits.

The two diastereoisomers dexamethasone (DXM) and betamethasone (BTM) were infused at two different doses (2, 10 mg.kg-1) in anesthetized rabbits. Samples of plasma and cerebrospinal fluid were collected over a 180-min period. Steroid concentrations were measured by high performance liquid chromatography. The terminal half life (85.7 +/- 20.8 min and 102.2 +/- 29.6 min for DXM; 117.6 +/- 19.8 min and 118.5 +/- 15.8 min for BTM) and the mean residence time (121.4 +/- 27.7 min and 146.1 +/- 41.3 min for DXM; 168.6 +/- 28.1 min and 172.2 +/- 20.6 min for BTM) were unchanged between the doses. Dose-dependent changes in the area under the curve normalized by the dose, then volume distribution and clearance were observed. The average percentage of DXM and BTM bound to plasma proteins were 78.1 +/- 11.5% and 88.3 +/- 5.1% respectively at the lower dose, and decreased significantly with 10 mg.kg-1. DXM appeared more rapidly in the CSF, the highest concentrations of DXM were obtained within 15 min after the end of the injection. The CSF levels were lower than that of plasma unbound and the passage through the blood-brain barrier was saturable. These results will complicate pharmacokinetic and pharmacodynamic analysis.

Animals↗
PubMed1994

Pharmacokinetics and brain distribution of zolpidem in the rat after acute and chronic administration.

The pharmacokinetics of zolpidem were studied after single dose, administered for either 7 or 28 days to rats. Thirty minutes after the last dose, animals were killed and the brain removed. The highest concentrations in plasma, which were observed at the first sampling time (0.5 h) were 2341 +/- 540 (day 0), 1956 +/- 325 (day 7) and 2908 +/- 1369 ng mL-1 (day 28). Corresponding AUC values of 1742 +/- 488, 1583 +/- 422 and 2683 +/- 1249 ng mL-1 h were found. MRT increased significantly from 0.46 +/- 0.06 h on day 0 to 0.67 +/- 0.02 h on day 28. The cerebral levels showed no significant change during the chronic administration (766 +/- 285, 685 +/- 171 and 887 +/- 264 ng g-1, respectively). No modification of the principal kinetic parameters was detected up to the 28th day of treatment.

Animals↗
PubMed1993

Sensitive high-performance liquid chromatographic method for the determination of coumarin in plasma.

A high-performance liquid chromatographic method was developed for the determination of coumarin in plasma at low concentrations. The method involves a single-step extraction of the alkalinized sample with hexane and subsequent evaporation of the organic phase in the presence of hydrochloric acid to collect and concentrate the coumarin. Analysis of the acidic phase was performed on a C8 column and coumarin was detected by measuring the UV absorbance at 275 nm. The limit of detection was 0.3 microgram l-1. The assay was used to study the evolution of concentrations of coumarin in one volunteer after oral administration of a single 10-mg dose.

Calibration↗
PubMed1993

Gas chromatographic determination of meprobamate in human plasma.

A simplified and rapid gas chromatographic method has been developed for the determination of meprobamate in human plasma. The procedure includes a single-step extraction of alkalinized sample with chloroform, and chromatography on a non-polar fused-silica capillary column with flame ionization detection. The method is accurate (97.7 +/- 5.7% at 20 mg/l) and precise (maximum coefficient of variation of 9.5%). It provides an alternative to existing methods and is particularly suitable for toxicological studies.

Aged↗
PubMed1992

[The risks of pyrimethamine-sulfadoxine combination in the prenatal treatment of toxoplasmosis].

Some of the alternative treatments to avoid termination of pregnancy in cases where the fetus is affected by toxoplasmosis is to treat it as soon as the diagnosis has been made. The authors who already have experience of using pyrimethamine with sulfadoxoine (Fansidar) in the post-natal treatment of congenital infection, thought after reviewing the literature that this association of drugs would be harmless if applied during pregnancy. The principal risk that arises in the fetus is the teratogenicity of each of the components of pyrimethamine and sulfadoxine and also their associations. In animals pyrimethamine can increase the frequency of cleft palates probably because of its antifolinic action but there is no formal proof that it is teratogenic in human beings. Furthermore, the theoretical risk of karnicerus in the new born using the Sulfonamide has not been demonstrated. In the mother the main but rare risk (1 in 75,000) seems to be for the production of severe skin lesions such as Lyell and Stevens-Johnson which could be brought about by sulfonamides, but not particularly sulfadoxine.

Antimalarials↗
PubMed1991

Influence of sex and oestrogen replacement on the disposition of dexamethasone in rats.

The disposition of dexamethasone (DXM, 2 mg/kg, iv) was studied in ovariectomized female rats treated with oestrogen (0.1 mg and 1 mg of oestradiol benzoate) and in male rats. Oestradiol replacement had no effect on body or liver weights or on the DXM pharmacokinetic parameters (CL, Vdss, AUC, MRT and t1/2) of the female groups. If the Vdss seemed slightly greater in male than in female rats, this difference disappeared after normalization based on body weight. In contrast, CL was greater in the male rats even after normalization. For all the animals, significant correlations were observed between body weight and Vdss (r = 0.731, P less than 0.001) or CL (r = 0.639, P less than 0.001). Terminal half life and MRT were negatively correlated with CL (r = -0.481, P less than 0.01 and r = -0.575, P less than 0.01, respectively) but not with Vdss. Although oestrogen replacement did not seem to affect the pharmacokinetics of DXM, the increase in the CL in male rats should be the main determinant observed between the sexes. These results are consistent with a slower metabolism found for various drugs metabolized by the cytochrome P-450 in female rats.

Analysis of Variance↗
PubMed1990

Lack of interaction between disulfiram and alprazolam in alcoholic patients.

Certain interactions between disulfiram and benzodiazepines, especially diazepam and chlordiazepoxide, have previously been reported. The influence of disulfiram on the pharmacokinetics of alprazolam, a triazolobenzodiazepine, metabolized by hepatic microsomal oxidation, has been evaluated in 11 chronic alcoholic patients (6 males, 5 females) undergoing treatment for the alcohol withdrawal syndrome. Each patient received alprazolam 2 mg on the first day (control) followed by two weeks of treatment with disulfiram 0.5 g/d, and then further oral dose of alprazolam 2 mg. No significant change was found in any of the kinetic parameters. Thus, a therapeutic dose of disulfiram did not significantly alter the clearance or half-life of alprazolam in chronic alcoholic patients.

Adult↗
PubMed1989

[Value of determining dexamethasone in the rapid adrenal suppression test].

During the dexamethasone suppression test (DST), we evaluated the relationship between the 8 a.m. dexamethasone (DXM) level and the pharmacokinetics of this corticoid after the oral administration of a single dose at midnight of DXM (1 mg) in 7 healthy subjects. The half-life time of the terminal phase for DXM was 283 min +/- 132 min (mean +/- s.d.). The 8 a.m. DXM level, which is positively correlated with the DXM half-life time, is useful for the interpretation of the DST. On the other hand, no correlation was observed between the 8 a.m. plasma cortisol and DXM levels in 21 healthy subjects. However, the negative correlation between the dose of DXM/kg and post-DXM cortisol level suggests the possibility of adjusting the dose of DXM in obese patients.

Administration, Oral↗
PubMed1989

[Psychotropics and pregnancy. Apropos of 2 case reports: the dose of triazolam].

In this paper the authors report on two term-birth newborn infants who were exposed to long-term maternal treatment with benzodiazepines. They emphasize the free interval before the onset of respiratory pauses in these newborns, since triazolam is classified as belonging to the class of benzodiazepines with ultra-rapid elimination and especially the severity of these disorders.

Apnea↗
PubMed1986

[Plasma levels of clomipramine and declomipramine in patients with depression: a study of its correlation with therapeutic efficacy].

Twenty four in-patients with an endogenous or non endogenous depressive syndrome (9 and 15, respectively) were treated in hospital for 21 days with various dosages regimens of clomipramine. Plasma concentrations of clomipramine and demethylclomipramine were determined once a week in blood samples. Therapeutic effects were assessed with Hamilton Rating Scale. At day 21, optimal therapeutic effect was observed when the sum of clomipramine and demethylclomipramine plasma levels was situated between 200-400 ng/ml.

Adolescent↗
PubMed1984

[Bone and blood levels of azlocillin after intra-arterial injection in the dog].

Pharmacokinetic values of azlocillin--a semisynthetic penicillin of the ureidopenicillin family--were determined in dogs after injection of the drug into the right femoral artery by measuring plasma concentrations in the right femoral artery and left femoral vein and tissue concentrations in ipsi- and contralateral bones. Two different doses of azlocillin were administered, one group of dogs receiving 100 mg X kg-1 by fast (1 min) bolus injection and the other group receiving 250 mg X kg-1. The drug was assayed by high performance liquid chromatography in reverse phase, which proved to be the simplest, most rapid and most sensitive method. Changes in plasma and bone tissue concentrations after intra-arterial injection were interpreted as order one kinetics with a two-compartment open model. Following the 100 mg/kg dose, concentrations versus time corresponded to the following equations: --Arterial blood (mg/l) = 7570 e-0.15 t (min) + 240 e-0.017 t --Venous blood (mg/l) = 553 e-0.13 t + 222 e-0.016 t --Bone tissue (micrograms/g) = 15 e-0.0115 t (elimination phase). Distribution and elimination constants were identical in arterial and venous blood. Distribution half-life was 5 +/- 1 min in arterial blood and biological half-life was 42 +/- 11 min. However, bioavailability was comparatively lower in veins due to higher levels in arteries during the distribution phase. Bone tissue concentrations were much lower than plasma concentrations and were identical on both sides despite high arterial levels on the ipsilateral side during the distribution phase. Bone concentrations diminished rapidly and elimination kinetic values were the same in bone and in plasma. It is concluded that bone tissue concentrations of azlocillin after intra-arterial injection are highest during the distribution phase.

Animals↗