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Biomedical subjects

J P McCormack

Publications and source records attributed to J P McCormack.

24 records · Page 2Linked to original sources
PubMed1987

Potential impact of quantitative susceptibility tests on the design of aminoglycoside dosing regimens.

Therapeutic drug monitoring of aminoglycosides currently applies pharmacokinetic principles to maintain peak concentrations between 4 and 10 micrograms/ml and troughs less than 2 micrograms/ml. These predetermined concentrations are based on statistical rates of cure and incidences of adverse effects. At present, recommended serum concentration ranges for aminoglycosides (as with other antibiotics) do not specifically target the susceptibility of the individual organism, but compensate only for altered clearance due to diseases. The design of antibiotic regimens based on both pharmacokinetics and pharmacodynamics is called dual individualization. Logically, the pharmacodynamic parameters, the minimum inhibitory concentration (MIC) of the organism and the postantibiotic effect (PAE), should also play a significant role in design of the dosing regimen. Simulations were performed to examine the consequences of designing aminoglycoside regimens considering both disease effects on excretion and bacterial susceptibility (MIC and PAE). The application of dual individualization concepts to aminoglycosides argues for a wider range of dosage requirements than observed with regimens that maintain desired peaks and troughs. If these concepts are accepted, some patients will clearly require more aminoglycoside than is currently used, and others can be managed with substantially less. The aminoglycoside therapeutic window, as it is now conceived, could be markedly different in the future.

Aminoglycosides↗
PubMed1986

Interference of digoxin-like immunoreactive substances with three digoxin immunoassays in patients with various degrees of renal function.

The effect of renal function and digoxin use in adult patients on interference from digoxin-like immunoreactive substances (DLIS) with three digoxin immunoassays was studied. Hospital patients entered into the study were categorized into the following groups according to renal function: group I (serum creatinine less than 1.5 mg/dL), group II (serum creatinine 1.5-2.5 mg/dL), group III (serum creatinine greater than 2.5 mg/dL, not on hemodialysis), and group IV (serum creatinine greater than 2.5 mg/dL, on maintenance hemodialysis). Medical records were reviewed to determine whether or not patients were receiving digoxin. Excess sera for analysis of serum digoxin concentrations (SDCs) was collected from routine laboratory tests. Serum samples were assayed singly by fluorescence polarization immunoassay (FPIA, Digoxin I, Abbott), radioimmunoassay (RIA, Micromedic), and affinity-column-mediated immunoassay (ACMIA, aca, E.I. du Pont). Correlation of SDCs obtained by RIA and ACMIA with FPIA results was determined using linear-regression analysis. A total of 177 patients met the study criteria; 98 were receiving digoxin. In patients on digoxin, SDCs by RIA were significantly higher than those obtained by FPIA in group II and III patients. SDCs obtained by ACMIA correlated well with and were not significantly different from those obtained by FPIA in any of the patient groups. Maximum differences and mean absolute differences in SDCs obtained by RIA were greater than those for ACMIA when compared with FPIA values in all patient groups. Over 40% of patients with renal dysfunction not on digoxin had false-positive SDCs by RIA; the highest of these values was seen in groups II and III.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗