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At least 631 records · Page 35Linked to original sources
PubMed1978

Guide to oral theophylline therapy for the treatment of chronic asthma.

Theophylline, when used appropriately, seems to be the most effective noncorticosteroid prophylactic medication for chronic asthma. Dosage, however, requires consideration of the relationship between serum concentration, efficacy, and toxicity, in addition to the variability in rates of elimination. Therapy is initiated with 16 mg/kg/day or 400 mg/day (whichever is less) in divided doses at appropriate intervals depending on the rate of absorption of the product used. If side effects are absent, the dosage is increased at three-day intervals until the age-related mean dosage necessary to produce a therapeutic level, is reached. Final dosage adjustment is generally based on a single determination of serum concentration; dosage requirements generally then remain constant for six to 12 months depending upon the child's growth rate. Dosage adjustment in this manner optimizes benefit, minimizes risk of toxic effect, and avoids excessive numbers of serum theophylline measurements.

Administration, Oral↗
PubMed1978

Increased tyrosine phenol-lyase activity in mice following pyridoxal phosphate administration.

A limiting factor in the depletion of plasma tyrosine following tyrosine phenol-lyase injection into normal mice was found to be the availability of an essential cofactor, pyridoxal phosphate. Because of the extremely short half-life of this cofactor, adequate elevation of circulating cofactor levels for prolonged periods by injection of a pyridoxal phosphate solution was not practical. Similarly, long-term diets enriched with pyridoxine and pyridoxal phosphate did not significantly improve the efficiency of the injected holoenzyme. A repository dosage form was devised that consisted of an s.c. implant of pyridoxal phosphate suspended in a spermaceti and peanut oil mixture. Under these conditions a sustained increase in holoenzyme activity levels and a significant resulting decrease in plasma tyrosine levels were obtained.

Animals↗
PubMed1978

Sustained-release theophylline therapy for chronic childhood asthma.

The efficacy of continuous, around-the-clock sustained-release (S-R) theophylline therapy, adjusted to approximate serum or plasma steady state theophylline concentrations (Tc) of 15 microgram/ml three hours following the last dose, was assessed in 18 children suffering from moderately severe chronic asthma. Two of the three formulations studied, Slo-Phyllin Gyrocaps and Theo-Dur, had excellent bioavailability and produced stable therapeutic Tc throughout an eight-hour dosing interval, using average doses of 8.7 +/- 0.5 and 8.4 +/- 0.6 (SE) mg/kg/dose, respectively. Pulmonary function responses paralleled Tc and were also stable throughout the dosing interval. Aerolate provided comparatively less stability, and higher doses (11.3 +/- 0.7 mg/kg) were necessary to produce therapeutic Tc. Toxicity was not evident when dosage was adjusted to avoid Tc exceeding 20 microgram/ml. S-R theophylline therapy, with the use of formulations of acceptable bioavailability, provides excellent control of chronic childhood asthma, offers the advantage of extended dosing intervals, and encourages improved patient cooperation in drug compliance.

Adolescent↗
PubMed1976

[Drug-drug interactions (author's transl)].

This short outline of drug-drug interactions does not claim to cover the entire field. The task of this paper is to illustrate the most important principles of drug-drug interactions by paradigms taken from the experience of the practitioner. One consequence of drug-drug interactions is the change in pharmacolinetic parameters important for the therapeutical effect of drugs in the organism. Very often the elucidation of the mechanisms of drug-drug interactions in man is impossible; therefore, for clinical pharmacologists experiments on animals remain the tool in order to gain more knowledge in this field.

Age Factors↗
PubMed1976

[Galenical possibilities and problems in protraction of drug effects (author's transl)].

In recent years, dosage forms with sustained release have obtained a significant importance. The technological possibilities for manufacturing are described as coating, embedding and matrix procedures. The range of auxiliary substances, which are responsible for the retardation of drug activity, reaches from lipophilic compounds as lipoids, fatty alcohols and compounds which are forming hydrogels as cellulose derivatives and natural polysaccharides to synthetic polymers derived from acrylic acid. The formulation of the dosage forms requires particular care in respect to the amount of initial and maintenance doses. On account of technological processes, for example during manufacturing of tablets, under certain circumstances the liberation rate is altered. In vitro test methods allow comparisons only then when the results can be counter-checked by in vitro experiments. The release of drug follows different mechanisms, which are described, entirely or in part, to be reactions following the time law of zero or first order. In special cases, a linear correlation is observed as a function of square root of time. The calculation of given special equations for events within the dosage form is feasible from blood-level values.

Biological Availability↗
PubMed1976

[The influence of neuroleptic drugs on urinary excretion of non-protein nitrogen (author's transl)].

During treatment with thioxanthenes or phenothiazines of schizophrenic patients non-protein nitrogen in urine was measured. The values were calculated in relation to the excretion of creatinine. a) Flupentixol or fluphenazine applied in optimal dosage, increased the excretion of urea and the amino acids asp, glu + gln, and gly. b) Moreover, if the drug induced a parkinsonoid (thioridazine) the excretion of ser and thr was increased, too. The usual desalting procedure by ion-exchanging resins before chromatography increases the contents of several amino acids, e.g. asp, asn, ala, gly, cys, ser, thr, indicating a breakdown of some instable products.

Amino Acids↗