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Biomedical subjects

K Borner

Publications and source records attributed to K Borner.

At least 55 records · Page 3Linked to original sources
PubMed1990

Pharmacokinetics of ofloxacin and adequacy of maintenance dose for patients on haemodialysis.

Seven patients, three females and four males, aged 33-70 years, with end-stage renal disease, on regular haemodialysis were treated for various infections with a loading dose of 200 mg and multiple maintenance doses of 100 mg ofloxacin per 24 h over ten days orally. The pharmacokinetics of ofloxacin were studied at the end of the treatment period before, during and after a haemodialysis session. Concentrations in plasma and dialysate were measured by HPLC. Mean trough concentration (+/- S.D.) of ofloxacin before the last drug intake was 1.6 (+/- 0.6) mg/l. At a Tmax of 1.5 (+/- 1.1) h a peak concentration of 3.1 (+/- 1.0) mg/l was reached. The mean half-lives of ofloxacin (+/- S.D.) which were determined in the dialysis-free interval (T1/2 beta) and during the haemodialysis session (T1/2HD) were 38.5 (+/- 14.1) h and 9.9 (+/- 3.4) h, respectively. Mean dialyser clearance (+/- S.D.) was 59.2 (+/- 15.4) ml/min and the fractional removal of ofloxacin amounted to 21.5 (+/- 8.2)%. The data show that in patients with regular haemodialysis treatment a loading dose of 200 mg orally and daily administration of 100 mg orally of ofloxacin results in therapeutically favourable and well tolerated plasma concentrations when given at the end of haemodialysis.

Adult↗
PubMed1990

Concentrations of ofloxacin in human bone and in cartilage.

Concentrations of ofloxacin were determined in bone, cartilage and serum of 23 patients (8 male, 15 female; age 29-85 years) who underwent total hip replacement for osteoarthritis. A single dose of 200 mg ofloxacin was infused over a period of 20 min. Blood specimens (total 89), bone (45), and cartilage specimens were taken up to 720 min after the infusion. Ofloxacin was determined by high performance liquid chromatography. Bone was extracted with buffer three times to obtain a complete extraction. An average bone density of 1.9 kg/l was assumed in order to convert concentrations from mg/kg to mg/l bone. Mean serum concentrations decreased from 7.2 +/- 2.6 (0 min) to 0.5 +/- 0.1 (720 min). Mean tissue concentrations (mg/l) at 98, 246 and 716 min after the end of infusion were, in cortical bone 0.64 +/- 0.29, 0.86 +/- 0.55 and 0.59 +/- 0.14; in cancellous bone, 1.70 +/- 0.72, 1.47 +/- 1.00 and 0.99 +/- 0.43, and in cartilage 1.38 +/- 1.05; 2.19 +/- 1.56 and 2.18 +/- 0.45. The half-life of ofloxacin in tissues was longer than in serum. No side effects were observed.

Adult↗
PubMed1990

Pharmacokinetics of FCE 22891, a new oral penem.

FCE 22891 is the oral prodrug of FCE 22101, a new broad-spectrum penem. The pharmacokinetics of FCE 22891 after single-dose administration, its absolute bioavailability, and the effect of food intake on its absorption were investigated in three different randomized crossover studies in healthy volunteers. Drug levels in blood and urine were measured by high-pressure liquid chromatography and bioassay. For optimal comparison of the results of all studies, and since there was good agreement of both methods, only the high-pressure liquid chromatography results are included. The pharmacokinetics of the penem were linear, and its bioavailability after oral administration was 42 +/- 11%. Food intake increased the total area under the curve from 0 h to infinity from 11.9 +/- 3.5 to 14.1 +/- 2.4 mg.h/liter. A specific side effect, i.e., bladder complaints, was registered in some volunteers taking FCE 22891 at doses greater than or equal to 1.0 g.

Administration, Oral↗
PubMed1990

Pharmacokinetics of ciprofloxacin in liver cirrhosis.

The pharmacokinetics of ciprofloxacin were evaluated in 11 patients (3 patients with impaired renal function) with advanced liver cirrhosis after a single oral dose of 500 mg. Mean serum peaks were 2.80 +/- 1.00 mg/l in 64 +/- 37 min after intake in patients with normal renal function. Elimination was reduced in comparison with healthy volunteers: t1/2 beta 510 +/- 158 min with a total area under the curve of 18.2 +/- 10.3 mg x h/l. Mean recovery of the parent compound from urine was 38 +/- 9% of the dose. In 3 patients with cirrhosis plus poor renal function, elimination was markedly reduced. In patients under 60 years with good renal function, the standard does not require a reduction.

Administration, Oral↗
PubMed1990

Comparative pharmacokinetics of glycopeptide antibiotics, and the influence of teicoplanin on granulocyte function.

The glycopeptide antibiotics teicoplanin and vancomycin differ in their pharmacokinetic properties. Teicoplanin is characterized by a high and prolonged serum concentration as a result of its long elimination half-life, which can be explained by high serum protein binding and renal tubular resorption. The apparent volume of distribution of teicoplanin is much larger than the extracellular space of the human body, indicating intracellular accumulation in different tissues. Elimination is primarily via the kidneys, though 15-20% is eliminated by non-renal mechanisms. Vancomycin has a shorter elimination half-life and lower protein binding than teicoplanin. At therapeutically relevant serum concentrations, teicoplanin has no influence on superoxide anion production and enzyme release by granulocytes.

Cells, Cultured↗
PubMed1990

Efficacy of sustained release theophylline given at three different evening intake times in addition to a baseline medication.

In this randomized crossover study of 26 outpatients with bronchial asthma the efficacy of a new once-daily theophylline formulation given in addition to a baseline medication was investigated; moreover, under steady state conditions, the effect of three evening intake times (6, 8 and 10 p.m.) on 24 h pharmacokinetics and peak-expiratory flow profiles was evaluated. The theophylline dose had been individually titrated. The pharmacodynamic results show a marked improvement of 24 h peak expiratory flow values after adding theophylline to a drug therapy including inhalative beta 2-agonists and corticosteroids in nearly all and inhalative anticholinergics in 50% of the treated outpatients. No significant differences between the pharmacokinetic characteristics and the 24 hr averages (mesors) of peak expiratory flow at the three different intake times 6, 8 and 10 p.m. were found; however, intake at 10 p.m. resulted in the highest nocturnal excess of serum theophylline concentrations and the highest peak expiratory flow during the early morning hours between 2 and 6 a.m.

Asthma↗
PubMed1990

Prospective randomized clinical trials of new quinolones versus beta-lactam antibiotics in lower respiratory tract infections.

In four prospective randomized clinical trials between November 1983 and March 1988, we studied 270 patients with severe bacterial infections, mainly lower respiratory tract ones. We compared ciprofloxacin and imipenem/cilastatin in the first study, ciprofloxacin and ofloxacin in the second study, ciprofloxacin and ticarcillin/clavulanic acid in the third study, and ofloxacin and cefpirome in the fourth study. A total of 90 pneumonias, 139 LRTIs, 22 septicaemias and 19 other bacterial infections were treated; the dominant pathogens were Pseudomonas aeruginosa and enterobacteria. Clinical success rates were high; cure or improvement was registered in 89% of the patients on ciprofloxacin, 89% on ofloxacin and 85% on beta-lactams. Treatment failures occurred mainly in ICU patients with terminal underlying diseases. Bacteriologically, eradication rates were high for enterobacteria and Staphylococcus aureus, but a relatively high persistence rate was seen for P. aeruginosa due to increased resistance and/or specific type and location of the infections. The incidence of side-effects was relatively high (23%-29%) which was related to careful monitoring. Adverse effects were group-specific (CNS reactions with quinolones, diarrhoea with beta-lactam antibiotics).

Cilastatin↗
PubMed1990

Penetration of ciprofloxacin into the spinal fluid in patients with viral and bacterial meningitis.

Cerebrospinal fluid (CSF) concentrations of ciprofloxacin (Ciprobay) were measured by high performance liquid chromatography (HPLC) in 20 patients with varying degrees of meningeal inflammation. Underlying clinical syndromes were viral meningitis (n = 10), convalescent phase of acute bacterial meningitis (n = 9), and acute phase of bacterial meningitis (n = 1). CSF concentrations following an intravenous dose of 200 mg ranged between 0.028 and 0.11 mg/l (5.8-26.8% of corresponding serum levels) in patients with viral meningitis, and between 0.049 and 0.389 mg/l (5.9-77.0% of corresponding serum levels) in patients with bacterial meningitis. Taken together with the findings of other authors, the results indicate a potential usefulness of ciprofloxacin as an alternative agent for treatment of meningitis due to susceptible gram-negative microorganisms.

Adult↗
PubMed1989

Ciprofloxacin intravenous dose variance.

Following different intravenous dosages of ciprofloxacin in volunteers, only limited variation in serum concentrations have been reported using volunteers in both single- and multiple-dose studies. In patients, a greater variability in serum concentrations was reported during intravenous ciprofloxacin treatment. This was also the case in patients with varying degrees of renal insufficiency. However, no report exists of nonmeasurable ciprofloxacin serum concentrations during intravenous treatment in patients.

Adult↗
PubMed1989

Combination effects of ciprofloxacin, clindamycin, and metronidazole intravenously in volunteers.

Despite the broad antibacterial spectrum of ciprofloxacin, most anaerobic organisms are resistant to the drug, whereas several gram-positive organisms are only moderately susceptible. Thus, in some clinical situations, combined treatment with ciprofloxacin and metronidazole or clindamycin could be useful. Therefore, the pharmacokinetics and serum bactericidal activities of ciprofloxacin in combination with clindamycin or metronidazole were investigated using a randomized crossover study design in 10 healthy volunteers. Ciprofloxacin (200 mg) was administered alone and in combination with clindamycin (600 mg) or metronidazole (500 mg); all drugs were given intravenously over 30 minutes. Serum and urine concentrations of the substances were measured using standard methods (high-performance liquid chromatography or gas chromatography). Blood samples for determination of serum bactericidal activity against five different aerobic and two anaerobic bacterial species (a total of 58 strains) were obtained one hour and six hours after drug infusion. All values were statistically analyzed by use of the Student t test.

Adult↗
PubMed1989

Quinine dosage in severe malaria with renal failure necessitating haemodialysis.

For therapy of severe malaria with renal failure, a 2/3 reduction in the usual intravenous dose of quinine is recommended (600 mg per 24 h instead of 600 mg per 8 h). Two patients with severe malaria and renal failure requiring dialysis have been treated. The half-life was not prolonged (15 h). Quinine proved to be nondialysable. It was shown that this dose of quinine tended to lead to a low level in blood (under 10 mg.l-1). A normal dose of quinine (2 x 15 mg/kg per day) is therefore recommended for malaria therapy, even in cases with renal failure requiring haemodialysis, in order to attain the desired plasma level (5 to 15 mg.l-1).

Chromatography, High Pressure Liquid↗
PubMed1989

Regular analgesic intake and the risk of end-stage renal failure.

The strength of the association between regular analgesic intake (RAI) and end-stage renal failure (EF) has been insufficiently established until now. A case-control study was conducted to estimate the relative risks (RR) of EF after RAI (defined as consumption of 15 or more analgesic doses per month for a continuous period of at least 1 year) for cumulative drug intake, single-ingredient analgesics, combinations, and specific compounds. The case group included all patients with EF undergoing renal replacement therapy in the area of West Berlin (1984-1986, n = 921). Control subjects, matched to cases by sex, age, and nationality, were selected from a group of patients in outpatient clinics. Matching was possible for 517 cases. The RR of EF after RAI of any analgesic was 2.44 (95% confidence interval: 1.77-3.39) and after RAI of combination drugs 2.65 (95% confidence interval 1.91-3.67). No significant increase was found, however, after RAI of single-ingredient analgesics. The RR after RAI of combination drugs and for the most preferred analgesic ingredients (phenacetin, paracetamol, acetylsalicylic acid, phenazones, caffeine) increased with dose. Furthermore, a dose-time-related RR after RAI of the longest used preparation was found. Thus, the results clearly show an increased RR of EF after RAI related to both dose and exposure time of mixed analgesic compounds, but not for the use of only single-ingredient analgesics.

Adult↗
PubMed1989

Multivariate analysis of aminoglycoside levels in hemodialysis patients.

Multivariate discriminant analysis was performed on data for 50 consecutive hemodialysis patients who had received aminoglycoside treatment because of severe bacterial infections. The 10 of the 60 clinical parameters considered to be most important were survival of patients (28/50 patients), success of treatment (27/50 patients), acute or chronic renal failure (15 vs. 35), age (54 +/- 17 years), creatinine level (675 +/- 298 mumol/l), artificial ventilation (21/50 patients), need for catecholamines (19/50 patients), continuous arteriovenous hemofiltration (9/50 patients), duration of therapy (12 +/- 8 days) as well as aminoglycoside peak (7.5 +/- 2.7 mg/l) and trough levels (3.6 +/- 1.3 mg/l). The 4 of the 10 parameters investigated by multivariate analysis significantly contributing to survival of patients were clinical success of aminoglycoside treatment (p = 0.0001), no need for catecholamines (p = 0.0001), duration of dosage (p = 0.003) and aminoglycoside peak levels (p = 0.009).

Adolescent↗
PubMed1989

Unique aspects of quinolone pharmacokinetics.

Despite some limited differences in pharmacokinetic parameters among the newer quinolones, their pharmacology is characterised by high volumes of distribution, long elimination half-lives, good to excellent bioavailability, low protein binding, limited biotransformation and different elimination pathways (mainly through the kidneys). The unique aspects of quinolones in comparison with beta-lactams and aminoglycosides are their higher volumes of distribution, longer elimination half-lives and their intracellular high concentration, especially in phagocytic cells.

4-Quinolones↗
PubMed1988

Comparative pharmacokinetics of intravenous ofloxacin and ciprofloxacin.

In ten volunteers the pharmacokinetics of ofloxacin and ciprofloxacin were determined after crossover administration of 100 and 200 mg intravenously (30 min constant infusion). Concentrations in serum and urine were measured by HPLC. Concentrations in serum following parenteral ofloxacin dosages demonstrated dose dependency with long biological half-lives. Pharmacokinetic parameters were calculated on the basis of an open three-compartment model, which resulted in a high volume of distribution for both substances (166-246 1 for ofloxacin, 178-2611 for ciprofloxacin). AUC for ofloxacin was three times higher than that for ciprofloxacin. Approximately 80% of ofloxacin and 57% of ciprofloxacin were eliminated through the kidneys. Ciprofloxacin had a considerable amount of extrarenal clearance, whereas only 19% of ofloxacin were eliminated by extrarenal mechanisms. Only 4.3% of ofloxacin after iv dosing could be detected as metabolites in urine.

Adult↗
PubMed1988

Pharmacokinetics and serum bactericidal activity of vancomycin alone and in combination with ceftazidime in healthy volunteers.

The pharmacokinetics and serum bactericidal activity of vancomycin alone and in combination with ceftazidime were investigated in 10 healthy volunteers. The pharmacokinetic parameters showed no significant differences (P less than 0.05) between single and combined administration. No antagonistic effects were observed in serum bactericidal activity with the combination against 20 gram-positive and 20 gram-negative locally isolated bacteria. A titer of greater than or equal to 1:8 was generated by the combination against all test strains except enterococci. Seven of ten volunteers developed a typical "red man's syndrome" during the administration of 1.0 g of vancomycin.

Adult↗
PubMed1988

[Concentration of metronidazole in bones].

Bone and serum concentrations of metronidazole were determined in 16 patients receiving a single dose of metronidazole before total hip replacement. The patients gave written informed consent to the procedure. Bone specimens were taken during the operation. Metronidazole was determined in serum and bone by high-performance liquid chromatography (HPLC). 30 to 85 minutes after i.v. infusion of 0.5 g metronidazole (infusion period 20 min.) concentrations in bone ranged from 3 to 25 mg/l. Metronidazole appears suitable for treatment of mixed infections of bone by anaerobes with proven sensitivity. Metronidazole should always be given in combination with another suitable antibiotic.

Aged↗