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D Reinhardt

Publications and source records attributed to D Reinhardt.

At least 163 records · Page 9Linked to original sources
PubMed1983

Pharmacokinetics of dexamethasone in children.

A pharmacokinetic data analysis of plasma level data for dexamethasone obtained from children with various diseases and healthy adults was performed. A total of 33 subjects participated in the study. The results show: The pharmacokinetics of dexamethasone can be described satisfactorily within the frame of classic linear pharmacokinetic theory. The variance of important pharmacokinetic parameters is large. Therefore, if a close relationship between drug levels and therapeutic and adverse effects exists, which still has to be proved, optimal individual dosage regimens have to be calculated, guided by drug-level monitoring. When treating newborns, one should be aware that high drug levels are likely to occur, possibly necessitating a dose reduction.

Adolescent↗
PubMed1983

[Developing a dose-administration schedule for drug therapy in childhood].

For the application of a target concentration strategy for the assessment of dosage regimens pharmacokinetic parameters and their variances must be known. Since pharmacokinetic parameters like the elimination constant or the volume of distribution undergo considerable changes during the perinatal period until early childhood, the application of standard dosage regimens may lead to serious under- or overtreatment. Based on kinetic data of children from the literature and own studies, it is demonstrated, how changes of the volume of distribution and of the elimination constant influence the optimal dosage regimen. The optimal dosage regimen is evaluated using a special criterion of optimality.

Age Factors↗
PubMed1983

[Pharmacokinetics of drugs from the breast-feeding mother passing into the body of the infant, using theophylline as an example].

In order to find out whether theophylline medication during the lactation period would produce hazards in the suckling infant or not, the following investigations were performed: 1. After oral application of theophylline to 12 nursing mothers the pharmacokinetics of the translactal passage was determined by simultaneous measurements in serum and milk. 2. For predicting the drug uptake by the suckling infant a pharmacokinetic model was designed allowing estimations of drug uptake by the infant on the basis of the kinetics of the translactal passage and the kinetics of the drug in the infant. The following results were obtained: 1. Theophylline passes the blood milk barrier with a certain delay. The time courses of theophylline in the milk thus were depressed when compared to those in the serum. The milk/plasma-quotient varied within a range of 0.6 to 0.89 and was less when maxima of theophylline in plasma were reached. Elimination half-lifes did not differ, but the apparent volume of distribution was greater in milk. This difference showed a good correlation to the divergent areas under the curves for milks and serum concentrations. 2. The kinetic data of the translactal passage of theophylline and the kinetic data of theophylline in infants were fitted into the kinetic model presuming constant dosage intervals as well as constant amounts and intervals of drinking. Theophylline accumulation occurred highly dependent upon the half-life in the infant. This accumulation reached therapeutic levels and even could surpass these when long half-lifes were assumed. For the estimation of drug transfer from breast feeding mothers to their infants via breastmilk, several pharmacokinetic criteria should be considered.

Breast Feeding↗
PubMed1982

Kinetics of the translactal passage of digoxin from breast feeding mothers to their infants.

In order to find out whether digoxin therapy of nursing mothers might produce discomfort in suckling infants we have investigated the kinetics of the transfer of digoxin from plasma to milk in 11 nursing mothers. After intravenous or oral application of a single dose of 0.5 mg or 0.75 mg digoxin simultaneous serum, fore- and hindmilk samples were taken. Obviously, a rapid equilibrium occurred between the serum and the milk compartments and there was no difference between fore- and hindmilk. All three digoxin concentration profiles ran parallel with a milk to serum ratio of 0.6 to 0.7. The curves could best be fitted by the sum of two exponential functions. For predicting the digoxin intake into the suckling infant, simulations were carried out on the basis of two coupled compartment models. When the kinetic milk data as well as the kinetic data obtained in infants were fitted by this model it could be shown that even in the case of long half-lives only about 3% of the therapeutic drug levels were reached in the baby. Thus, one can conclude that digoxin accumulation to toxic concentrations should not occur in infants of women treated with appropriate doses of digoxin.

Adult↗
PubMed1982

Lymphocyte capping in muscular dystrophies.

Since reports of lymphocyte capping in muscular dystrophies of various authors revealed controversial results, we investigated 47 patients and carriers with Duchenne or Becker-Kiener muscular dystrophy according to different methods. There was no significant reduction of cap formation compared to 64 healthy controls, both groups showing a mean of about 75% caps. Reduced numbers of caps, however, could be demonstrated in three otherwise healthy probands aged 70 years or more, two patients under interferon treatment, four patients under high dose methotrexate therapy as well as one patient with untreated chronic myeloic leukemia. Thus lymphocyte capping in our experience is far from being a valid method for carrier detection or prenatal diagnosis of muscular dystrophies.

Adolescent↗
PubMed1982

[Parathormone and vitamin d3-metabolites in healthy children and children with chronic renal failure before and after kidney transplantation].

Immunoreactive parathyroid hormone (iPTH), 25(OH)D3, 24,25(OH)2D3, 1.25(OH)2D3, creatinin, phosphate and calcium were determined in 33 children suffering from chronic renal failure as well as in 7 healthy children serving as a control group. In 9 children with preterminal renal insufficiency and in 13 children who had to undergo hemodialysis iPTH and creatinin were closely related. In the hemodialysed children's group serum phosphate was significantly elevated whereas calcium did not different from the control group. Treatment with vitamin D3 showed in those children undergoing hemodialysis increased 25(OH)D3 in normal 1.25(OH)2D3 plasma levels. Nevertheless, in the children with preterminal renal insufficiency as well as the children under hemodialysis iPTH was significantly increased. Thus, it is suggested that a negative feed back regulation controls the synthesis of 1.25(OH)2D3. After kidney transplantation the serum levels of iPTH, the vitamin D3 metabolites and creatinin became normal. There was no correlation between iPTH and 25(OH)D3 or 1.25(OH)2D3, but the correlation with creatinin (P less than 0.05, r = 0.7) before and after transplantation was statistically significant. Thus, the alterations in vitamin D metabolism and the hyperparathyroidism in chronic renal osteodystrophy appear to be largely independent of each other.

Adolescent↗
PubMed1982

Linear elimination kinetics but non-linear pharmacodynamics in theophylline intoxication in a child.

In an infant's acute theophylline intoxication following a medication error, plasma levels above 80 micrograms/ml were not associated with repetitive seizures, but also with heart rates above 200 bpm. The serum elimination kinetics were characterized by a first-order elimination process with a half-life of 15 h. Despite the exponential decay of plasma levels the heart rate remained at a high level during the first 20 h. This behavior is explained by a saturation phenomenon familiar in receptor and enzyme kinetics.

Female↗
PubMed1982

[The differential diagnosis of the unilateral by hyperlucent lung. Two case reports (author's transl)].

The "unilateral hyperlucent lung" is a roentgenologic diagnosis based on an increased radiolucency of one lung. Aetiology and pathogenesis of this clinical syndrome are discussed together with two own case reports about a 9-year-old girl and a 3-month old boy. Anamnesis, bronchography, scintigraphy and angiocardiography in the girl revealed a Swyer-James syndrome, where typically only one lung is damaged by obliterating bronchiolitis. In the patient the pulmonary changes developed subsequently to a measles-pneumonia, possibly enhanced by an additional pollinosis. The 3-month old infant had a left-sided pulmonary artery hypoplasia and obstructive bronchitis in both lungs. Up to its 7th month of life the child developed sufficiently under conservative therapy, but then a life threatening pneumonia with obstructive bronchitis and respiratory failure occurred, 3 weeks of artificial respiration were without success. The subsequent pneumectomy revealed a hypoplasia of the left lung and a big tracheal cyst as cause of the severe obstruction.

Age Factors↗
PubMed1982

Methods for evaluating optimal dosage regimens and their application to theophylline.

For a certain class of drugs blood levels can be used to monitor therapy. Based on the concept of a target concentration strategy criteria for optimal treatment schemes are given. The goal of these criteria is to define dose regimens that lead to concentrations within the target concentration range. The performance indices of these criteria are evaluated and applied to the dose regimen assessment for theophylline.

Administration, Oral↗
PubMed1981

[Drug effects on embryo and fetus. 2. Diaplacental transport of drugs].

Drugs administered in pregnancy have primarily as their target the mother, and the embryo or fetus is an unwanted recipient. Only in a few cases therapy of the growing child via the mother is intended. Thus the knowledge of the risk-benefit ratios of various drug regimens during pregnancy is a matter of utmost concern to each physician. Experimental and clinical data show that there is no direct relationship between the chemical structure, the pharmacological activity or the toxicity of a drug in the adult and its specific action on the embryo. Nevertheless, the considerations presently known to be involved in determining whether a drug will be teratogenic and toxic or not mainly depend upon the type of drug, duration of dosage, access to the conceptus, developmental embryonic stage at time of dosage, disposition within the fetus and individual susceptibility. We have attempted to summarize the present knowledge concerning drug disposition in the embryo and fetus. In addition, based upon the mathematical evaluation of some new experimental results the pharmacokinetics of diaplacental drug transfer is demonstrated.

Biotransformation↗