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Biomedical subjects

G C van der Aa

Publications and source records attributed to G C van der Aa.

5 recordsLinked to original sources
PubMed1997

[An uneasy balance].

Impairment of mobility is common in older people. Early detection of this impairment can identify persons at risk of a decrease in the ability to perform activities of daily living, recurrent falls and deconditioning. Using only standard neuromuscular and orthopedic examinations physicians may overlook important deficits in mobility. Direct assessment is necessary to identify such deficits. Several formal gait assessment instruments are available, such as the Tinetti performance-based mobility assessment. In order to illustrate the additional value of functional assessment the medical history of two patients is described.

Accidental Falls↗
PubMed1991

Comparison of steady-state serum concentrations of digoxin in tablets (Lanoxin) and capsules (Lanoxicaps) in the elderly.

The bioavailability of digoxin in solution (Lanoxicaps, 90-100 percent) is superior to that of Lanoxin tablets (60-80 percent) in young healthy volunteers. The alleged bioequivalence of digoxin in tablets (Lanoxin 0.25, 0.125 mg) and capsules (Lanoxicaps 0.2, 0.1 mg) was studied in 20 elderly inpatients (14 women, 6 men, aged 84 +/- 5 years), treated with digoxin for atrial fibrillation. In a crossover design, steady-state digoxin concentrations were measured in 16 patients after once-daily administration of Lanoxin 0.125 mg or Lanoxicaps 0.1 mg, each for at least ten days. Four other patients took Lanoxin 0.25 mg and Lanoxicaps 0.2 mg successively. The steady-state digoxin concentrations were statistically significantly different, being 1.3 +/- 0.5 nmol/L for Lanoxin and 0.9 +/- 0.4 nmol/L for Lanoxicaps (p = 0.003). Whereas in young healthy volunteers the bioavailability of digoxin from Lanoxicaps (90-100 percent) exceeds that from Lanoxin (80 percent), in elderly patients the absorption appears to be similar. This suggests a lower than expected bioavailability of Lanoxicaps, which may result in subtherapeutic serum concentrations.

Aged↗
PubMed1984

[A patient with depression due to digitalis poisoning].

A 85 year old lady suffering from depression is described. The depression was caused by digoxin intoxication. At first this was not recognized because of the low level of creatinine in the serum. This was the result of the decreased lean body mass, the patient weighing only 40 kilo!

Aged↗
PubMed1984

[Pharmacokinetics of digoxin in the aged].

Many elderly are treated with digitalis preparations. Both over- and under-dosage occur often. To obtain better dosage the pharmacokinetics of digoxin are discussed, as well as changes in it in the process of ageing. The body composition changes with ageing: the fat content increases and the lean body mass decreases. Moreover there is an important sex difference for all age categories. The decrease in lean body mass causes a decrease in distribution volume of digoxin. Furthermore it causes a decrease in creatinine production, masking the (physiological) decrease in glomerular filtration rate by 'normal' plasma creatinine levels. To estimate the renal function, determining digoxin elimination, with the plasma creatinine level, a formula is discussed with other parameters (weight, age, sex), that enables a reliable estimate. The renal function thus found enables estimation of the daily eliminated fraction. Combination of this estimate with a loading dose, reduced regarding the decreased distribution volume , results in a daily dose.

Aged↗