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Biomedical subjects

E Rey

Publications and source records attributed to E Rey.

At least 145 records · Page 8Linked to original sources
PubMed1985

Studies on methyl-xanthines in intact and hypophysectomised rats: differences in pharmacokinetics and adrenocortical response.

The effects of caffeine (Cf), theophylline (Tph) and theobromine (Tb) on the adrenal cortex were studied. No direct effect (hypophysectomized: hypo(-) rats) was observed with any of the three methyl-xanthines (MX) after chronic oral administration (5 days). An indirect effect (via the hypothalamo-hypophyseal-adrenal axis) was found for theophylline: plasma and adrenal corticosterone levels were increased in intact rats, after acute or chronic treatment. The high toxicity of MX (mainly Tph) observed in hypo(-) rats prompted the study of pharmacokinetic parameters: the clearance was decreased and the half-life was increased by a factor 3 for Cf and 1.6 for Tph. Thus, the elimination of Cf and Tph was slowed down in hypo(-) rats.

Adrenal Cortex↗
PubMed1984

[Interaction between tiapride and alcohol in man].

Results of a study in nine alcoholic patients designed to investigate the effects on wakefulness of tiapride combined with alcohol are presented. Each patient was given successively alcohol, tiapride, and both. Changes in certain psychomotor performances during each of these three periods are described. In the study patients, the tiapride-alcohol combination produced no detrimental effect on wakefulness; on the contrary, results of one of the tests were improved.

Arousal↗
PubMed1984

[Premedication using intrarectal midazolam. Study of effective dosage in pediatric anesthesia].

The object of this study was to determine the optimal dose of midazolam given per rectum which would produce sedation adequate for inducing inhalational anaesthesia in paediatric practice. Five doses were studied: 0.15, 0.25, 0.30, 0.35 and 0.40 mg X kg-1. The criteria used to appreciate the effectiveness of the sedation at 30 min were the change in the child's behaviour, with a scale of 6 levels, and the acceptance of the mask and anaesthetic vapours. There was a significant correlation between the dose administered and the degree of sedation, as well as between the dose administered and the lack of reaction to the mask. Significantly better results were found with the higher doses of 0.35 and 0.40 mg X kg-1, when compared with the children who had received 0.15 and 0.25 mg X kg-1. Only in the groups who received 0.35 and 0.40 mg X kg-1 were the degrees of sedation and acceptance of induction considered as adequate. The dose of 0.35 mg X kg-1 seemed to be the best dose for adequately premedicating a child.

Age Factors↗
PubMed1984

Pharmacokinetics of buflomedil after intravenous administration in patients with chronic renal failure.

The pharmacokinetics of single intravenous doses of buflomedil were studied in nine patients with chronic renal failure. The mean buflomedil half-life was 5.38 h (range 1.78-11.8 h); the mean buflomedil total clearance was 11.8 l/h (range 2.67-37.2 l/h). Comparisons of buflomedil kinetic parameters between the uraemic patients and healthy subjects revealed significant decreases in the renal elimination percentage u, the renal clearance Clr; significant increase in elimination half-life from the central compartment and no significant differences in the other parameters. Chronic renal failure is associated with a significant alteration in buflomedil elimination. This study suggests to reduce the usual dosage to half its value in the renal disease.

Adult↗
PubMed1983

[Monotherapy with clobazam in epilepsies in children].

Twenty-five epileptic children were treated with clobazam alone for periods of 10 days to 36 months (mean = 9 months and 16 months for children who responded well). Satisfactory results were obtained in 11 patients and marked improvement with a 75% decrease in the initial frequency of seizures in 6 patients. The seizures recurred after a few weeks in 3 other patients. This preliminary study shows that clobazam is well tolerated and remarkably effective, especially in benign partial epilepsy, even in carbamazepine-resistant cases.

Adolescent↗
PubMed1983

Pharmacological interaction between nitroglycerin and aspirin after acute and chronic aspirin treatment of healthy subjects.

The interaction between nitroglycerin (NTG) and aspirin was investigated in 7 healthy subjects in order to test whether aspirin could block the haemodynamic response to NTG; the doses used were NTG 0.8 mg, and aspirin 0.5 g for chronic and 1 g for acute treatment. The plasma levels of NTG and various physiological parameters (heart rate, diastolic arterial pressure, end diastolic diameter, and end systolic diameter) were measured during the 30 minutes after the administration of NTG. An increase in NTG Cmax and AUC was observed after both aspirin treatment. The changes in physiological parameters produced by NTG were enhanced by the two treatments, although the differences were not statistically significant. The results indicate complex pharmacokinetic and pharmacodynamic interactions between NTG and aspirin.

Adult↗
PubMed1983

[Benzodiazepines and pregnancy. Transplacental passage, labor and lactation].

Benzodiazepines (BZD) are lipophilic molecules, undissociated agents which easily penetrate membranes. Pharmacokinetics of BZD arises from these chemico-physical properties. Thus BZD show a rapid placental transfer with significant uptake of the drug, in both early and late pregnancy. The changes in the placental structures and in the circulation of the uterus during pregnancy are responsible in the greater placental passage in late pregnancy. After repeated doses in pregnant women, BZD tend to accumulate on the fetus, and the " flappy infant" syndrome may occur. The disposition of diazepam in women to the end of the pregnancy is altered. The terminal half-life is about twice as in non pregnant control, the distribution volume is increased but the total plasma clearance is not changed. In neonate child and particularly in premature infant, elimination of the BZD is slower in relation with immaturity of the hepatic enzymes systems metabolising drugs. BZD appear in human milk, but only high clinical doses might be expected to exert an effect on the nursing newborn. In the first trimester of pregnancy use of BZD has to be exceptional; the safety of these products in early pregnancy has not yet been definitively established. In the late pregnancy and at the parturition, there are more clear indications. Generally high single doses and repeated and prolonged administrations have to be avoided.

Anti-Anxiety Agents↗
PubMed1983

[Monotherapy with carbamazepine in childhood epilepsies].

68 epileptic children were treated with carbamazepine (CBZ) monotherapy for a mean period of 10 months. The seizures disappeared in 43% and decreased in another 26.5% of cases. The treatment was particularly efficient in partial benign epilepsies (disappearance: 64.7%, reduction: 29.4%) and in partial unclassifiable epilepsies (disappearance: 50%, reduction: 25%). It is sometimes useful to achieve blood levels over 4 micrograms/ml; but over 8 micrograms/ml the frequency of side-effects becomes greater than improvement of fit frequency. The dose-concentration relation is well correlated to age, so that blood level measurements do not need to be systematically performed. In order to obtain mean blood levels of 7 micrograms/ml 3 to 4 hours after morning intake, mean daily dose should range from: 20 mg/kg/24 h before 5 years to 10 mg/kg/24 h after 10 years.

Adolescent↗
PubMed1982

[Comparative pharmacokinetics of benzodiazepines].

The pharmetabolism properties allow to guide the therapeutic use of benzodiazepines. The authors have studied these two aspects in relation with absorption, routes of administration, protein binding, distribution, métabolism, excretion, long-term use. The paper also deals extensively with pharmacokinetics and metabolic modifications under the influence of drug interaction, age, physiologic condition (pregnancy, new-born, elderlies) and pathological condition. These data are useful to guide the choice according to indication and to adapt the dosage.

Adult↗
PubMed1982

Transfer of ritodrine and norepinephrine in human placenta: in vitro study.

The placental transfer from maternal to fetal circulation of ritodrine, a tocolytic agent used in obstetrics and of a structurally related physiologic catecholamine, norepinephrine was studied in vitro using dual perfusion of isolated human placental lobules. The clearances of ritodrine and norepinephrine represent 34 and 24% respectively of tritiated water clearance taken as reference. The relatively low ritodrine clearance may be explained by its small molecular weight and hydrosoluble nature, but not that of norepinephrine. For the latter, a strong membrane limitation and efficient placental catabolism may be implicated. We conclude that some of the fetal effects of maternal infusion of these amines are the result of the method in which the drug is transferred.

Biological Transport, Active↗
PubMed1982

Maternofetal transfer of two benzodiazepines. Effect of plasma protein binding and placental uptake.

The influence of plasma protein binding on the maternofetal transfer of diazepam was studied in the perfused human placental lobule. Substitution of buffered salt perfusate in both maternal and fetal circuits for a perfusate with plasma proteins did not alter diazepam transfer significantly. Diazepam placental uptake was shown to be important in perfusion, with both types of perfusates. Comparison with the less liposoluble and less protein-bound benzodiazepine, fosazepam, revealed a marked difference in placental uptake but not in maternofetal transfer. In incubation studies, the kinetics of placental uptake confirmed this difference.

Blood Proteins↗
PubMed1982

Pharmacokinetics of tiapride and absolute bioavailability of three extravascular forms.

The pharmacokinetic properties of a single 200-mg dose of tiapride were studied in eight healthy volunteers (four males and four females). The drug was administered by i. v., i. m., and p. o. routes (solution and tablets). Plasma and urine concentrations were determined by a high-performance liquid chromatography. The results were compatible with a linear two-compartment model. The half-life in the disposition phase ranged from 2.19 h to 4.55 h (mean 3.23 h). Peak plasma concentrations were always reached within 2 h. The percentage of absorption of the i. m. and the two p. o. formulations varied from 49.3 to 98.9%. The renal clearance varied from 11.8 to 24.9 l/h. The drug was mainly eliminated in unmetabolized form in the urine (75.6%).

Absorption↗
PubMed1981

Opposite effects of lorazepam on two kinds of myoclonus in the photosensitive Papio papio.

The action of lorazepam was studied in photosensitive baboons. Animals were either naturally very photosensitive or rendered photosensitive by a previous injection of allylglycine. Intravenous administration of varying doses, from 0.05 to 0.5 mg/kg, of lorazepam blocked the myoclonus induced by intermittent light stimulation in all the animals. However, in the naturally photosensitive baboon the injection of lorazepam favoured the appearance of spontaneous myoclonus with no important EEG modification. This myoclonus is different from that induced by intermittent light stimulation, which is always preceded by spike-wave cortical discharges. Lorazepam-induced myoclonus appears during the period when the animal is not photosensitive and its origin is probably in the medulla or in the brain stem.

Animals↗