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Biomedical subjects

O Paulsen

Publications and source records attributed to O Paulsen.

At least 55 records · Page 3Linked to original sources
PubMed1988

No effect of oral N-acetylcysteine on the bioavailability of erythromycin and bacampicillin.

In vitro studies with N-acetylcysteine (NAC) solutions used for inhalation treatment have demonstrated inactivation of some antibiotics by NAC. Oral NAC treatment is increasingly common for long-term prophylaxis in chronic bronchitis. During exacerbations, treatment with oral antibiotics will often be given simultaneously. We assessed the effect of simultaneous oral administration of NAC on the bioavailability of two antibiotics in ten healthy volunteers. No effect of NAC was found on the bioavailability of ampicillin, after administration of the prodrug bacampicillin. A slight, but not significant statistical increase in erythromycin serum levels was seen with NAC. Acetylator phenotype did not influence the absorption of NAC, which seemed slightly reduced by bacampicillin, but significantly increased by erythromycin. No decrease of antibacterial activity of sera was found in vitro after the addition of NAC or the related thiol glutathione, employing micrococcus luteus and staphylococcus aureus as indicator organisms.

Acetylcysteine↗
PubMed1987

Determination of erythromycin in human plasma, using column liquid chromatography with a polymeric packing material, alkaline mobile phase and amperometric detection.

A method based on column liquid chromatography was developed for determination of plasma concentrations of erythromycin. PRP-1, a polymeric type of packing material suitable for chromatography and amperometric detection at high pH, was used. The effect of pH on the column performance and on the electrochemical response was studied. A pH of ca. 10 was found to be optimal. After extraction with tert.-butyl methyl ether, plasma concentrations down to 0.2 mumol/l could be measured, using automated sample injection. Oleandomycin was used as internal standard. The method was used for determination of plasma concentrations in a pharmacokinetic study under steady-state conditions.

Chromatography, Liquid↗
PubMed1987

The interaction of erythromycin with theophylline.

We have studied the interaction of erythromycin with theophylline. We gave ten healthy volunteers theophylline as an intravenous loading dose (5 mg X kg-1) over 1 h, followed by a maintenance infusion (0.5 mg X kg-1 X h-1) for 5 h. A second infusion of theophylline was given after 9 days of treatment with 1 g erythromycin base daily, and the concentrations of theophylline were determined during the infusion periods. The concentrations of erythromycin were measured for 8 h, after one week of treatment, and also after the last erythromycin dose, simultaneously with the second theophylline infusion. Concentrations within the therapeutic range were obtained with both drugs. A significant increase in both AUC and mean plasma concentrations of theophylline was seen during erythromycin treatment. The plasma clearance of theophylline was reduced in 9 of the 10 subjects. Renal clearance increased correspondingly, but the change was not statistically significant. Serum concentrations of erythromycin fell significantly, by more than 30%, with concurrent theophylline medication. We conclude that an interaction between theophylline and erythromycin, affecting both drugs, can be shown with concentrations of the drugs within the therapeutic range.

Adult↗
PubMed1987

Effects of ampicillin on the elimination of enprofylline in man.

The effect of intravenously administered ampicillin on plasma levels and renal clearance of enprofylline was investigated in seven young and six elderly volunteers. On one occasion, each subject received 2 g of ampicillin intravenously, and serum concentrations of ampicillin were followed for 4 hours. On a separate occasion, a loading infusion of enprofylline was administered over 60 min., aiming at a plasma level of 2 micrograms/ml, and followed by a maintenance infusion. During this an infusion of 2 g of ampicillin was given for 10 min., and subsequently, renal clearance and plasma levels of enprofylline were followed for 4 hours. Plasma enprofylline levels increased significantly in the subjects after ampicillin infusion, but the effects on renal clearance of enprofylline were not statistically significant. The magnitude of the effects on enprofylline plasma levels and renal clearance from high doses of ampicillin do not suggest that interaction with beta-lactam antibiotics will be a serious problem for patients on enprofylline treatment.

Adult↗
PubMed1987

Interaction between isoniazid and theophylline.

Metabolic interactions between theophylline and several other drugs have been described in a number of studies. They may be of importance because of the narrow therapeutic range of theophylline. A significant risk for interactions has been considered to exist only with drugs metabolized by oxidative enzyme systems, and thus is not expected to occur with isoniazid. However, an increased clearance of theophylline with oral isoniazid medication has been reported. On the other hand, we found a significant increase in plasma levels of intravenously infused theophylline, and a corresponding decrease in plasma clearance of theophylline, when isoniazid was administered orally, compared to similar infusions in these individuals without concomitant isoniazid medication. The effect was seen irrespective of acetylator status. In five of the seven subjects an increase of isoniazid half-life and AUC was seen with theophylline, but this increase was not statistically significant.

Acetylation↗
PubMed1986

Pharmacokinetics of N-acetylcysteine in man.

N-Acetylcysteine was given intravenously and as three fast dissolving and one slow-release formulation, on separate occasions, as a single dose of 600 mg to 10 fasting (5 men and 5 women) healthy volunteers. Blood and urine were sampled for the following 12 h. Renal clearance constituted around 30% of total body clearance, which was 0.21 l/h/kg. Volume of distribution was 0.33 l/kg, consistent with distribution mainly to extracellular water. The late elimination half-life was 2.27 h and the mean residence time 1.62 h. The slow-release tablet resulted in a flattened plasma concentration-time curve typical of slow release formulations, while the other three oral formulations were rapidly absorbed. The oral availability of N-acetylcysteine varied between 6 and 10%, with the slow-release tablet having the lowest and the fast dissolving tablet the highest availability.

Acetylcysteine↗
PubMed1986

No interaction between H2 blockers and isoniazid.

Antacids and anticholinergic drugs may delay gastric emptying and cause reduced absorption of isoniazid, but the influence of reduced gastric acidity has not been determined. In the present investigation, the influence of cimetidine and ranitidine on uptake and elimination of isoniazid was determined in six male and seven female healthy volunteers. The group comprised five rapid and eight slow acetylators, similar to the proportions in the general population. H2 blockers did not delay or reduce uptake of isoniazid, which thus seemed to be pH independent. Neither the acetylation of isoniazid nor the oxidative metabolism of acetylated isoniazid appeared to be affected by cimetidine or ranitidine.

Absorption↗
PubMed1985

Distribution of acetylator phenotype in relation to age and sex in Swedish patients. A retrospective study.

In 310 Swedish patients, the distribution of acetylator phenotype was studied by determination of the half-life of isoniazid (INH T1/2). The expected bimodal distribution was found in the complete study group, but was not always clearly apparent after subgrouping for age and sex. Mean INH T1/2 was higher in males and tended to increase with age. The difference in INH T1/2 between males and females was small in younger individuals (below 46 years of age) and showed a gradual increase with age. In older individuals (above 65 y) mean INH T1/2 was 42 min longer in males than in females. In the females, mean INH T1/2 was relatively constant in all age groups. The effect of age on acetylator phenotype, previously reported by other workers, appears to have been confirmed but only in males. It may be influenced by concurrent treatment for certain diseases.

Acetylation↗
PubMed1985

Cefadroxil once daily for three or seven days versus amoxycillin for seven days in uncomplicated urinary tract infections in women.

The cure rate of acute uncomplicated urinary tract infection in general practice using 3 different treatment regimens, was studied in a randomized, multicenter trial. Patients were assigned to receive either cefadroxil 1 g once daily for 3 or 7 days or amoxycillin 375 mg t.i.d. for 7 days. 310 patients entered the study, of whom 230 could be evaluated according to the protocol. Two thirds of the cases were due to infections with Escherichia coli and about one fourth to Staphylococcus saprophyticus. No statistically significant differences in cure rates between the 3 regimens could be demonstrated neither at 1 week nor at 5 weeks of follow-up. The frequency of adverse reactions was low and similar in each treatment group.

Amoxicillin↗
PubMed1981

Synovial fluid lactate determinations as a diagnostic aid in cases of monoarticular arthritis.

The concentration of synovial fluid lactate was determined by an enzymatic kit method in 16 patients with various types of monoarticular arthritis and in 2 patients with non-inflammatory lesions and no joint effusion. Lactate concentrations in control cases were 1.2 mmol/l, in septic arthritis above 10 mmol/l, in pseudogout and yersinia arthritis around 7 mmol/l, and in other cases of inflammatory, nonseptic arthritis around 3.0 mmol/l.

Adolescent↗