Biomedical subjects

I Nilsson-Ehle

Publications and source records attributed to I Nilsson-Ehle.

58 records · Page 4Linked to original sources

PubMed1976

Quantitation of antibiotics using high-pressure liquid chromatography: tetracycline.

A method for quantitative determination of tetracycline in serum, using high-pressure liquid chromatography, is reported. After extraction of the drug from serum, using methanol-trichloroacetic acid solution, tetracycline was separated by reverse-phase chromatography. Quantitation of tetracycline was based on a linear relationship between peak heights in the chromatograms and known concentrations of the drug in the original serum samples. Serum tetracycline concentrations as low as 0.3 mug/ml could be accurately measured. Serum samples obtained after a single intravenous injection of tetracycline to three human volunteers and six dogs were assayed by microbiological and chemical assays. Correlation coefficients of 0.95 and 0.97, respectively, were found. This chemical method is rapid (less than 30 min), accurate, sensitive, and reproducible, and it seems feasible for routine clinical use.

Biological Assay↗

PubMedDate not supplied

Pharmacokinetics of antimicrobial agents in the elderly.

Many elderly individuals are treated with antibiotics, but knowledge of the pharmacokinetic performance of the compounds in these patients is limited. Advanced age is accompanied by many physiologic alterations that may have secondary effects on absorption, distribution, metabolism, and excretion of drugs. Information on absorption and metabolism in the elderly is scarce and conflicting. Because renal excretion of penicillins and cephalosporins decreases with the physiologic signs of the kidneys, dose reduction is advisable in elderly patients. Monitoring of serum drug levels is recommended for the selection of correct dosages of renally eliminated antibiotics with a narrow therapeutic range--e.g., aminoglycosides and vancomycin. There is a considerable need for additional studies of the influence of age on the kinetics of antimicrobial agents.

Aged↗

PubMedDate not supplied

Gastrointestinal damage induced by cytostatic treatment does not affect the bioavailability of co-trimoxazole.

Twelve lymphoma patients received prophylaxis with co-trimoxazole during cytostatic treatment according to the MACOP-B regimen with cyclophosphamide, doxorubicin, vincristine, methotrexate, bleomycin, folinic acid and prednisone. Gastrointestinal mucosal damage from cytostatic treatment was estimated by WHO toxicity scores. No correlation was found between the degree of gastrointestinal damage and the presumed bioavailability of co-trimoxazole as estimated from serum levels of trimethoprim and sulphamethoxazole. The serum concentrations were above the minimum inhibitory concentration for Escherichia coli, Staphylococcus aureus and coagulase-negative staphylococci irrespective of the degree of toxicity. There is no apparent reason to change the dosing regimen of prophylactic co-trimoxazole when there is clinical evidence of damage to the gastrointestinal mucosa induced by chemotherapy.

Adolescent↗

PubMedDate not supplied

Quinolone disposition in the elderly. Practical implications.

The fluoroquinolones are antibiotics frequently used in infections that affect elderly individuals. The physiological aging process can profoundly affect the pharmacokinetics of drugs, necessitating adjustment of dosage regimens in the elderly. Changes in pharmacokinetics with age are mainly due to the progressive deterioration of renal function, with resultant lower clearance of drugs which are eliminated by the kidneys. Ofloxacin is almost totally renally excreted and elimination is slower in older age groups; a dose reduction is therefore recommended for this quinolone. Unexpected alterations in pharmacokinetics may occur, as exemplified by the increased bioavailability of oral ciprofloxacin in elderly subjects. This is a well-documented phenomenon of such significance that lower oral doses are advisable for the elderly. Renal clearance of ciprofloxacin decreases in old age, but because of substantial nonrenal elimination the total clearance is affected less. Studies of the pharmacokinetics of the other quinolones in old age are scarce. No data exist on the absolute oral bioavailability of norfloxacin, enoxacin and pefloxacin. Renal clearance seems to be reduced, but since no intravenous studies have been reported, the total and nonrenal clearances are unknown in the elderly. No safe conclusions can be drawn regarding the necessity of dose reductions from a pharmacokinetic point of view. However, reports of adverse reactions to quinolones in the elderly, especially concentration-dependent symptoms from the central nervous system, and the risk of interaction with other drugs, suggest the need for caution in determining dosages of all of these compounds in elderly subjects.

4-Quinolones↗