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Biomedical subjects

J Prandota

Publications and source records attributed to J Prandota.

At least 37 records · Page 2Linked to original sources
PubMed1986

Pharmacodynamic determinants of furosemide diuretic effect in children.

The pharmacodynamics of 1 or 2 mg/kg of furosemide administered as a single dose orally or intravenously were studied in 34 hospitalized children (ranging in age from 9 days to 16.5 years) with normal renal function. These patients were divided into 3 groups: infants (furosemide 1 mg/kg, intravenously); children with steroid-responsive nephrotic syndrome (furosemide 2 mg/kg, orally and intravenously); patients with urinary tract infections and mild hypertension (furosemide 2 mg/kg, orally). A statistically significant positive linear relationship was found in these groups between the furosemide urinary excretion rate and urine flow rate, but log dose-response curves to furosemide were found to vary between the groups of patients studied. This variability reflects differences in the relationship between the amounts of furosemide reaching active sites and the pharmacodynamic effect of the drug. No sigmoid-shaped log dose-response curve (i.e., one approaching a zero response at very low furosemide urinary excretion rates, and a maximum response at very high excretion rates) was attained in this study. This suggests that the capacity of the kidney tubules to respond diuretically to the administered doses of furosemide was not exceeded in the studied patients. However, in the infants, a very steep log dose-response curve to a 1 mg/kg intravenous dose of furosemide suggests that higher doses may not result in a significant increase in diuretic response in infants with reasonably normal renal function. The lowest mean furosemide urinary excretion rate associated with significant diuresis was 0.58 +/- 0.33 micrograms/kg/min. Also, a significant correlation was found between the amount (in milligrams), of furosemide excreted in the urine during the first 6 h after administration and the urine volume collected during that time (r = 0.71; p less than 0.001; number of measurements = 43).

Administration, Oral↗
PubMed1985

Clinical pharmacokinetics of changes in drug elimination in children.

This review mainly summarizes selected aspects of the present knowledge of drug elimination kinetics independent of developmental changes, with special attention given to clinical situations. The effects of different disease states, drug interactions, changes in urinary pH, induction of microsomal enzymes, competition for renal excretory mechanisms, possible enterohepatic recirculation, binding of drugs to tissues, effects of a drug on another drug's metabolizing organ, and dose-dependent elimination, on increase or decrease of drug elimination rates in children, have been presented. Based on the available data it seems that one may postulate the following conclusions: (1) that the distribution factors as well as changes in drug elimination capacities seem to play a role, perhaps with differing relative importance, during each of the maturational periods; (2) that the physicochemical properties of a drug and its dosage, as well as changes in the volume of distribution in children, in the course of certain disease states may have a significant effect on kinetics of drug disposition in the body; (3) that systemic clearance, a model independent parameter, rather than elimination half-life, a hybrid pharmacokinetic parameter, more accurately reflects elimination of some drugs from the body; (4) that each drug and every clinical situation may require the evaluation of the direct effect on pharmacokinetic processes, since general principles may not always apply; (5) that drug disposition studies should also be performed, if possible, on patients under actual clinical situations and receiving the usual therapeutic regime, and (6) that the half-life of colistin is independent of postnatal age which should serve as a warning not to generalize about drug excretion in the young infant.

Adult↗