PubMed Health⌕ Search

Biomedical subjects

S N Rasmussen

Publications and source records attributed to S N Rasmussen.

170 records · Page 10Linked to original sources
PubMedDate not supplied

Dicloxacillin and flucloxacillin: pharmacokinetics, protein binding and serum bactericidal titers in healthy subjects after oral administration.

The pharmacokinetics of dicloxacillin and flucloxacillin were studied in 12 healthy volunteers after oral administration. The participants received a single dose of either dicloxacillin (0.5 g, 0.75 g or 1.0 g) or flucloxacillin (0.75 g) in a cross-over fashion. Antibiotic concentrations were determined in serum and urine by bioassay and followed for 8 and 24 h, respectively. The three dicloxacillin dosages showed no significant differences for the serum elimination half-lives (t1/2 beta, median: 72 min). Comparing 0.75 g flucloxacillin with the same dose of dicloxacillin, no significant differences between the values of Cmax, t1/2 beta and AUC were found. Protein binding as determined by ultrafiltration in pooled serum was 94.7-96.2% for flucloxacillin and 96.4-97.2% for dicloxacillin. The serum bactericidal titers were similar for the two drugs. In conclusion, dicloxacillin and flucloxacillin showed similar pharmacokinetic behavior after 0.75 g doses in human volunteers.

Administration, Oral↗
PubMedDate not supplied

Antibiotic activity in serum following single and repeated oral administration of sodium fusidate in volunteers.

The pharmacokinetics of antibiotic activity were investigated in 10 healthy, female volunteers receiving a single oral dose of sodium fusidate (500 mg) followed after 48 h by repeated oral dosing of 250 mg b.i.d. for 5 consecutive days. By use of turbidimetry, drug-related antibiotic activity in serum was determined and expressed as fusidic acid equivalents. After a single dose and repeated dosing, the peak concentrations were (mean +/- SE): 30 +/- 3 micrograms/ml and 27 +/- 3 micrograms/ml, respectively (NS), and the trough concentration at steady state was 8.4 +/- 1.8 micrograms/ml. The experimental and predicted accumulation ratios were 2.1 +/- 0.1 versus 1.6 +/- 0.2, respectively (P < 0.16). By use of a model independent method, the terminal elimination half-lives were estimated to be 11 +/- 1 h and 13 +/- 2 h after a single dose and repeated doses, respectively (NS). The total clearances of antibiotic activity were 2.0 +/- 0.4 l/h after a single dose and 1.6 +/- 0.2 l/h after repeated doses (P < 0.11). Model dependent pharmacokinetic parameters were also obtained by fitting a two-compartment open model to the median serum concentrations which, with respect to half-life and clearance, gave values close to those observed by use of the model independent approach. Safety-wise, biochemical parameters were within the normal range. However, a statistically significant increase in ASAT and a decrease in leucocytes were observed. The tolerability of the drug was good and only minor adverse events were reported.

Administration, Oral↗
PubMedDate not supplied

Tetraethylammonium and p-aminohippurate as clearance markers for renal plasma flow in the rat during saline and glucose infusion.

Renal plasma clearances (C) of 14C-tetraethylammonium (TEA) and p-aminohippurate (PAH) as estimates of arterial renal plasma flow (ARPF) were evaluated in anesthetized rats during control conditions and during intravenous glucose infusion. Venous renal blood flow was measured directly by means of a servo-controlled pump, keeping the renal venous pressure constant. Arteriovenous extraction fractions (E = 1 - P(renal venous)/P(renal arterial)) for PAH averaged 88.3 +/- (SE) 0.8% in control rats and 82.0 +/- 0.9% in glucose-infused rats (p less than 0.001); E(TEA) averaged 92.0 +/- 0.6 and 90.1 +/- 0.6%, respectively (p less than 0.05). Under both experimental conditions, (C/E)PAH did not differ significantly from ARPF, while (C/E)TEA underestimated ARPF; the rate of extraction of TEA exceeded the rate of excretion by 15-20%, probably due to accumulation of TEA in renal tissue. It is concluded that, when corrected for E, C(PAH) is in general a more accurate estimate for ARPF than C(TEA). However, under conditions involving changes in plasma glucose levels C(TEA) may provide a better estimate of the effective renal plasma flow than C(PAH).

Animals↗
PubMedDate not supplied

Disposition of antipyrine and phenytoin correlated with age and liver volume in man.

The half-life and metabolic clearance rate (MCR) of antipyrine and phenytoin were determined in 14 young (mean age: 28.8 +/- 8.3 (SD) years] and in 14 elderly [mean age: 83.5 +/- 7.1 (SD) years] subjects and correlated with liver volume, which was determined by ultrasonic scanning, to see if an age-dependent difference in drug metabolism could be explained by a reduced liver weight with age. The size of the liver was smaller in the elderly subjects even when related to decreased body surface. A significant decrease in serum albumin in the elderly compared with the younger group was also noted. The half-life of antipyrine was significantly longer in the elderly than in the younger group, 756 +/- 318 and 465 +/- 110 minutes, respectively, and the MCR was correspondingly lower in the elderly even when calculated per litre of live volume, 22.8 +/- 7.8 and 36.3 +/- 8.9ml/minute/L liver volume, respectively. No significant differences in the 2 age groups were found in half-life and total clearance of phenytoin, but a reduced free phenytoin clearance was demonstrated in the elderly (240 +/- 92ml/minute/L liver volume) compared with the younger (325 +/- 81ml/minute/L liver volume) group. No significant correlation was found between liver volume and the half-life of antipyrine and phenytoin. However, a significant correlation was demonstrated between liver volume and MCR of antipyrine as well as between total and free clearance of phenytoin. No correlation was found between the half-lives of the 2 drugs, while a significant correlation existed between the clearance values. It is suggested that the age-dependent reduction in drug clearance is due not only to a smaller liver volume, but it also a result of a reduced capacity of the liver microsomes per unit of liver in the elderly. With regard to age-dependent changes in drug metabolism, the protein binding of the actual drug has to be taken into consideration.

Adult↗