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W Mühlberg

Publications and source records attributed to W Mühlberg.

28 records · Page 2Linked to original sources
PubMed1982

[Elimination of desacetyl cefotaxime in geriatric patients with multiple diseases].

Plasma concentrations of cefotaxime and desacetyl cefotaxime were determined by HPLC in geriatric patients with multiple diseases. Comparison with a younger control group of healthy volunteers showed a prolongation of half-life of CTX and dCTX in the older patients. A significant correlation between pharmacokinetic parameters of dCTX and other clinical and chemical parameters was found. Half-life of dCTX was positively correlated with age of the geriatric patients (P less than 0.05). There was also a significant relationship between CHE in serum and plasma peak concentrations of dCTX. Time until reaching plasma peak concentrations correlated closely with total bilirubin (P less than 0.01), CHE (P less than 0.001), cholesterol (P less than 0.01), and urea (P less than 0.01). Accumulation of the pharmacologically active metabolite dCTX could not be excluded in one patient with kidney disease. In accordance with other investigators it is recommended to reduce the dose of cefotaxime in geriatric patients with kidney diseases.

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PubMed1982

[Drug treatment in the elderly: special aspects of diuretics (author's transl)].

Age-dependent changes in the pharmacokinetics of two diuretics, spironolactone and triamterene, were investigated in 20 geriatric patients with multiple diseases. Average plasma concentrations of canrenone (both determined by High-Performance-Liquid-Chromatography (HPLC) and a fluorimetric method) were significantly higher in geriatric patients compared with a younger control group of healthy volunteers (p less than 0,002). There was also a significant positive correlation between age (of the geriatric patients) and the area under the plasma concentration curve of canrenone. Plasma concentrations of canrenone (measured by HPLC after 120 hours) were closely correlated with number of red cells in the geriatric patients (p less than 0,01). Maximum plasma concentrations of triamterene and its pharmacologically active phase-II-metabolite were clearly higher in the geriatric patients when compared with a younger control group of healthy volunteers. Maximum plasma concentrations of the phase-II-metabolite were inversely correlated with diastolic blood pressure (p less than 0,01). Plasma levels of triamterene and its phase-II-metabolite in the older patients seem to be influenced not only renal perfusion pressure but also by uric acid levels.

Age Factors↗
PubMedDate not supplied

Pharmacokinetics of diuretics in geriatric patients.

Pharmacokinetics of three diuretics (furosemide, spironolactone, and triamterene) were investigated in 70 geriatric patients. Comparing the data with the corresponding values of young healthy volunteers, mean plasma concentrations of furosemide and spironolactone (and peak concentrations of triamterene) were markedly higher in the geriatric patients. Different concomitant diuretic therapy (hydrochlorothiazide vs. piretanide) seems to influence the kinetic parameters of triamterene and its active metabolite in the geriatric patients. In elderly patients reduction or correction of the dosage seems to be necessary for all three diuretics investigated in our studies.

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PubMedDate not supplied

Pharmacokinetics of alprazolam in elderly patients with multiple diseases.

The pharmacokinetics of alprazolam (1 mg p.o.) were investigated (using a new developed HPLC-assay) in 10 multimorbid elderly patients (five female, five male; mean age 72.8 +/- 8.2 years, creatinine clearance 63.6 +/- 25.9 ml/min, weight 68.9 +/- 13.9 kg). Compared with young and elderly volunteers from other studies peak plasma concentrations of alprazolam were decreased while peak time and elimination half-life were increased. 'Second peak' plasma levels (correlated with age and creatinine clearance) occurred in eight of 10 elderly patients. The variability associated with the pharmacokinetic parameters in the multimorbid elderly patients was far greater than that observed in young and old healthy volunteers. Mean alprazolam concentrations in multimorbid patients aged 72 years or more were elevated as compared to 'younger' patients (age range: 63-71 years). Dose reduction should be considered in the older multimorbid patients.

Journal Article↗
PubMedDate not supplied

Age-dependent changes of the kidneys: pharmacological implications.

About 40% of the intoxications after drug administration occur in the elderly. A significant proportion of the disease states in elderly patients is related to adverse reactions to prescribed drugs. Declining renal function, a reduction in both renal blood flow and glomerular filtration rate, is a major contributor to drug toxicity in the elderly. Therefore, a review (based on newer papers from Medline) of age-dependent changes of the kidneys and their consequences for drug therapy in geriatric patients is presented. Renal changes that occur with aging are: a decrease of renal weight, a thickening of the intrarenal vascular intima, sclerogenous changes of the glomeruli, and infiltration of chronic inflammatory cells and fibrosis in the stroma. Altered renal tubular function, including impaired handling of water, sodium, acid, and glucose, is also frequently present in old age. Impaired 'endocrinologic' functioning manifested by changes of the renin-angiotensin system, vitamin D metabolism, and antidiuretic hormone responsiveness has been reported. The aging kidney is constantly exposed to the effects of a variety of potential toxic processes, i.e., drugs and chronic illnesses including hypertension, diabetes, and atherosclerotic disease. Renal changes that occur with aging also consist of impairment in the ability to concentrate urine and to conserve sodium and water. These physiological changes increase the risks of volume depletion and prerenal type of acute renal failure. A frequent cause of acute renal failure in the elderly is drug-induced nephropathy. Nonsteroidal anti-inflammatory drugs, antibiotics, and diuretics are most often involved. Due to the age-dependent decline of renal function, the pharmacokinetics of many drugs are altered in elderly patients. Therefore, the most important renal function to monitor with aging is the creatinine clearance. Changes in pharmacokinetics of many drugs and most decisions on drug dosage can be based on this information alone, as tubular functions of the kidney decrease at rates paralleling the age-dependent decrease in glomerular filtration rate (which is approximately measured by the creatinine clearance). As a conclusion, age-dependent changes of renal function are not only responsible for changes in pharmacokinetics and pharmacodynamics. In many cases, the kidneys are the target organ of adverse drug reactions too.

Aging↗
PubMedDate not supplied

[Pharmacokinetics of naftidrofuryl in multimorbidity in geriatric patients].

The present pharmacokinetic study of a drug used in geriatric patients with multiple diseases reveals that the half-life in the elderly was extended for about three times as long as in the corresponding control group. There are significant positive as well as negative correlations between the kinetic data and routine parameters of the metabolism. These statistical correlations should be controlled by experimental studies.

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PubMedDate not supplied

[Furosemide--pharmacokinetics in geriatric patients with multimorbidity].

20 geriatric patients with multiple diseases were administered a single intravenous dose of 40 mg furosemide. Furosemide plasma and urine concentrations were measured using a thin-layer chromatography method (25) and were fitted to an open 2-compartment model. Furosemide half-life was prolonged twofold in the elderly patients compared with a control group of younger adults. In the same way renal clearance and total clearance were markedly reduced in the geriatric group. The nonrenal clearance and the volume of distribution (beta) were not significantly altered. There were many significant correlations between clinical and biochemical data and pharmacokinetic parameters, especially between blood pressure and the area under the curve (AUC 0-infinity), total clearance and nonrenal clearance of furosemide. Our data suggest a special function of alpha-2-globulins in binding of furosemide. Renal function (i.e. creatinine clearance) was shown to be an important parameter for estimating the elimination rate of furosemide.

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