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Biomedical subjects

G Hitzenberger

Publications and source records attributed to G Hitzenberger.

At least 73 records · Page 4Linked to original sources
PubMed1982

Rapid and substantial lowering of human serum cholesterol by mevinolin (MK-803), an inhibitor of hydroxymethylglutaryl-coenzyme A reductase.

Mevinolin (MK-803) is a potent inhibitor of HMG-CoA reductase. After a placebo run-in period, mevinolin 5,15 or 50 mg, or placebo was given twice daily for 7-11 days under double -blind conditions ot 4 groups of 6 normocholesterolemic male volunteers. After 7 days, mean serum cholesterol fell 14%, 25% and 24% on 5, 15 and 50 mg, respectively, which was significantly greater than the fall on placebo (4%) in the case of the two higher doses (P less than 0.01). Serum triglycerides did not change significantly. Mevinolin was generally well-tolerated and there were no serious adverse effects.

Adult↗
PubMed1982

Effects of age and smoking on the pharmacokinetics of pindolol and propranolol.

1 Pharmacokinetic investigations were carried out in a group of 32 ambulant normal male volunteers in order to determine the effect of age and smoking on steady-state plasma levels of pindolol and propranolol. There were four groups of 8: young non-smokers (YNS), young smokers (YS), old non-smokers (ONS) and old smokers (OS). Each subject received, in a randomized cross-over sequence, 5 mg pindolol and 80 mg propranolol three times daily for 2 days with an interval of at least 14 days between the two treatment periods. 2 Neither age nor smoking was shown to have any influence on the time to reach a peak plasma level after pindolol or propranolol. Age, on the other hand, significantly increased the peak plasma levels and the areas under the plasma concentration time curves, and decreased the elimination rate constants, the differences between the age groups being more pronounced for propranolol than for pindolol. No effect of smoking on these parameters was observed. 3 Differences were found between pindolol and propranolol in respect of time to reach a peak plasma level, peak plasma levels and area under the plasma concentration time curves in the groups ONS and YS when related to the YNS control group. Changes observed (with the exception of the time to reach a peak level) tended to be less for pindolol and were considered to be of little clinical relevance.

Adult↗
PubMed1982

Influence of smoking and age on pharmacokinetics of beta-receptor blockers.

The influence of age and smoking on pharmacokinetics of pindolol and propranolol was investigated. Although there was a statistically significant difference in certain pharmacokinetic parameters (maximum plasma concentration, area under the curve, elimination constant and elimination half-life) between elderly patients (more that 60 years) and young persons (20-30 years) no significant differences were found as far as smoking and nonsmoking is concerned. This is in contrast with some reports in the literature. The higher plasma concentrations of both investigated drugs may be the result of a decreased metabolism of propranolol in older persons, in a decreased hepatic blood flow and a decreased renal elimination. Because of the lower sensitivity of beta-receptors in old persons, the higher plasma concentrations of beta-receptor blockers in this group of patients should not result in a diminished dose of the investigated beta-receptor blockers in the elderly.

Adrenergic beta-Antagonists↗
PubMed1982

[New aspects in the prophylaxis of myocardial reinfarction (author's transl)].

During the last 30 years several methods have been employed to reduce myocardial infarction and sudden death, rsp. The results with inhibitors of blood coagulation and platelet aggregation are somewhat controversial. Beta-receptor-blockers and sulfinpyrazone on the other hand have proven to be effective at least as far as reduction of sudden death is concerned. A multifactorial intervention program regarding rehabilitation has also been successful although this program may be difficult to use on a broader basis because of organization problems. The following concept may be followed: if there are no contraindications against beta-receptor-blockers and if the patients are younger than 65 years beta-receptor-blockers should be used because there are more studies with a larger number of patients are younger than 65 years beta-receptor-blockers should be used because there are more studies with a larger number of patients available providing their usefulness than for that of sulfinpyrazone. If there are additional indications for beta-receptor-blockers, as for instance hypertension the choice should be even easier. If there are on the other hand contraindications against beta-receptor-blockers or indications for a treatment with sulfinpyrazone such as hyperuricemia, sulfinpyrazone should be used. According to our knowledge such a treatment should be continued for a period of 5 months, a longer treatment seems not to be more promising.

Adrenergic beta-Antagonists↗
PubMed1982

[Determination of serum concentrations of aminoglycosides in the monitoring of therapy in neonates. I. Gentamycin].

We studied the serum concentrations of gentamicin by radio-immuno-assay in 22 sick prematures (birth weight 1713 +/- 469 g, prenatal age 33 +/- 3 weeks, postnatal age 12 +/- 9 days) receiving 2.5 mg/kg bid. Bactericidal concentrations were present in 91% but only 50% had normal serum concentrations and gentamicin half-lives. Gentamicin half-life decreased significantly (p less than 0.01) with postnatal age but there was no statistically significant correlation between gentamicin serum concentration and gestational age or birth weight. We therefore recommend 1. gentamicin serum concentrations to be monitored routinely in therapy of prematures especially in the first week of life, 2. to expand the dosage interval up to 18 hours (which is about the threefold half-life) in prematures during the first week of life.

Gentamicins↗
PubMed1982

Duration of the hypotensive effect of guanfacine.

Guanfacine given intravenously causes a brief rise in blood pressure. This is followed by a sustained decrease of blood pressure, accompanied in one case by a marked orthostatic effect. In addition to its lowering effect on blood pressure, guanfacine also reduces heart rate. The duration of action for up to 72 h is due to the long half-life of the drug. The main side effects observed are fatigue and sedation.

Adult↗
PubMed1982

The bioavailability of spironolactone hydrochlorothiazide combination preparation.

In a single-blind, randomized cross-over study the bioavailability of Spironothiazid (50 mg spironolactone, 50 mg hydrochlorothiazide) was investigated in six healthy male volunteers by comparing the same dose of the well-established drugs Aldactone dragees, 50 mg, and Esidrex tablets, 25 mg. After 6 days treatment with 2 X 1 Spironothiazid or 2 X 1 Aldactone dragees, 50 mg, plus Esidrex tablets, 25 mg daly, orally, the serum concentrations and the cumulative renal excretion of the active substances were measured after the morning dose on the 7th day of the study. Canrenone (the main metabolite of spironolactone) was measured fluorimetrically, hydrochlorothiazide was determined by gas chromatography. There was no statistically significant difference between the investigated drugs, neither in the areas under the curves nor in the cumulative renal excretion, thus indicating an identical bioavailability.

Adult↗
PubMed1981

[Pharmacokinetics of ceftizoxim (author's transl)].

Ceftizoxim is a new cephalosporin derivative, which is also effective against anaerobic rods. The tolerability is excellent. Its pharmacokinetics after parenteral administration of 2 g were investigated in 12 healthy male volunteers. The half-life was 1.40 +/- 0.41 hours, the total clearance 194 l/min. The urinary excretion of the biological effective antibiotic amounted to 66.26 +/- 25.71%. These figures are in the same order of magnitude as those of older cephalosporins.

Adult↗
PubMed1981

Pharmacokinetics and biotransformation of benzbromarone in man.

After administration of a single oral dose of benzbromarone 100 mg to 7 subjects, the maximum serum level was 1.84 +/- 0.87 mg/l, and the elimination halflife was 2.77 +/- 1.07 h. The major metabolite, benzarone, could be detected in serum 3 h after administration of benzbromarone, and the maximum serum benzarone level of 0.79 +/- 0.21 mg/l occurred after 6 h. Benzarone had an elimination half-life from serum of 13.52 +/- 2.18 h. Both substances were excreted mainly via the liver and bile. In urine only benzarone beta-glucuronide could be detected; it amounted to 1.55% of the benzbromarone dose.

Adult↗
PubMed1981

Enhancement of uricosuric properties of indacrinone by manipulation of the enantiomer ratio.

Racemic indacrinone is a high-ceiling, relatively long-acting diuretic. Both enantiomers have uricosuric activity, but the diuretic activity resides predominantly in the (-) enantiomer. Usual therapeutic doses of racemic indacrinone have only transient uricosuric activity, so that, as with other diuretics, hyperuricemia occurs. Sixty-five healthy men participated in a multicenter, double-blind, randomized, balanced, incomplete-block study comparing the effects on plasma urate and urate clearance of indacrinone (-) enantiomer 10 mg given concomitantly with 0, 10, 20, 40, and 80 mg (+) enantiomer (10/0, 10/10, 10/20, 10/40, 10/80), as single daily doses for 7 days. Hydrochlorothiazide (HCTZ) 50 mg daily and ticrynafen (T) 250 mg daily were controls. Each subject received two of the seven treatments, so that there were 18 subjects per treatment. On days 7 to 8, morning (mean of 0-hr values on days 7 and 8), HCTZ, 10/0, 10/10, and 10/20 elevated plasma urate by 8% to 16%. 10/40 was approximately isouricemic, and 10/80 and T lowered plasma urate by 13% and 41%. There were corresponding changes in urate clearance.

Diuretics↗
PubMed1981

[Bioavailability studies of two spironolactone-preparations (author's transl)].

In a preliminary open bioequivalence investigation of orientating character (n =4) a single 100 mg dose of spironolactone (study I) led to maximum canrenone plasma levels (determined by HPLC) of 126.5 +/- 28.4 ng/ml (standard formulation 1) and 130 +/- 13.1 ng/ml (test formulation 2). The corresponding values for the sum of the fluorogenic metabolites were 418.9 +/- 43.5 ng (eq)/ml formulation 1 and 469.9 +/- 80.3 ng (eq)/ml formulation 2. A comparison of AUCs for both total fluorogenic metabolites and canrenone showed no marked differences. In a 2nd cross-over bioequivalence study with multiple dosing, mean minimum steady-state levels of 102.5 +/- 14 ng/ml (formulation 1) and 98.1 +/- 14.1 ng/ml (formulation 2) were obtained for canrenone, and 389 +/- 35.8 ng (eq)/ml (formulation 1) and 391.4 +/- 18.9 ng (eq)/ml (formulation 2) for total fluorescence. The AUCs for post-steady-state elimination, starting with the final spironolactone dose on day 10, were comparable. They were calculated to be 13226 +/-828 ng (eq)/ml . h (formulation 1) and 13858 +/- 651 ng (eq)/ml . h (formulation 2) for total fluorescence, and 3222 +/- 217 ng/ml (formulation 1) and 3167 +/- 195 ng/ml (formulation 2) for canrenone. Both spironolactone formulations can be considered as bioequivalent. The elimination half-lives (t 1/2) after a single 100 mg dose of spironolactone are (Study I) 16.4--19.1 h for canrenone and 13.6--14.0 h for the sum of the active (i.e., antagonistic to aldosterone) metabolites. Certain therapeutic conditions (e.g. multiple dosing of 100 mg spironolactone with tau = 12 h, Study II) can lead to slightly increased t 1/2 values for both canrenone (18.6--21.4 (h)) and total fluorogenic metabolites (15.8--16.9 (h)). The steady-state level for both formulations is reached by the third day of treatment.

Adolescent↗
PubMed1981

Cardiovascular effects of diltiazem in healthy volunteers at rest, supine and erect, and during physical and mental stress.

The hemodynamic effects of diltiazem were investigated in six volunteers at rest, supine and erect, under psychologic stress and orthostatic conditions. Plasma concentrations were also estimated. Under all conditions diltiazem showed a vasodilating property that was more pronounced on the arterial resistance vessels than on the pulmonary vessels. The first plasma concentrations were detected 15 min after drug intake, and the highest values were seen at the end of the study in the 3rd h.

Adult↗
PubMed1980

[Is endogenous creatinine clearance a sound basis for estimation of elimination half life of gentamicin?].

The elimination half life of gentamicin after intravenous administration of 80 mg of Refobacin was determined experimentally in 24 patients with normal and variably reduced renal function in the agar diffusion test. Experimentally found elimination half lives were compared to values determined from the creatinine clearance. Although there was good correlation between both parameters, satisfactory agreement between experimentally determined and calculated half life was found only in patients with normal or slightly reduced renal function. With decreasing creatinine clearance the calculated value was constantly bigger than the measured value, and the range of both values increased. Gentamicin treatment in patients with grossly decreased renal function should thus be performed under control of serum levels.

Adult↗
PubMed1980

[Pharmacokinetics, tolerance and therapeutic effect of trimethoprim-sulfametrol-infusions (author's transl)].

Lidaprim was administered as infusion to 6 healthy volunteers for 10 days in an interval of 12 hours for calculation of the pharmacokinetic parameters. Furthermore 31 patients with various severe infectious diseases were treated for 5-27 days with 2 or 3 infusions daily. Local tolerance was excellent. Side effects were observed only in 1 patient, who developed a rash. The cumulation equilibrium is reached for trimethoprim and also for total and free sulfonamide on the 3rd day. The clinical results were excellent: 22 of the 31 patients with severe infectious diseases could be cured.

Clinical Trials as Topic↗
PubMed1980

[Pharmacokinetics of trimethoprim and sulfametrol in patients with end stage renal failure and hemodialysis treatment (author's transl)].

In 6 patients with regular dialysis treatment the pharmacokinetics of intravenously administered trimethoprim and sulfametrol were investigated not only during dialysis procedure but also during the dialysis-free interval. Half-life of the free plasma sulfametrol component is normal even in cases with absent renal function and can be markedly reduced by hemodialysis treatment. The N4-acetylated main metabolite of the sulfonamide is - similar to trimethoprim - hardly dialyzable. Half-life of the latter drug component is prolonged in patients with far advanced renal failure. Due to the excellent dialysanceof the free plasma sulfonamide component the elimination of total sulfametrol is normal during hemodialysis despite cumulation of the N4-acetylated metabolite. Because of the tendency of this metabolite to cumulation, in dialysis patients the compound preparation of trimethoprim and sulfametrol should be used only for trasient treatment of acute infections.

Adult↗
PubMed1980

[Pharmacokinetics and tolerance of Cefazedone compared with Cefazoline (author's transl)].

In a randomized cross over study Cefazoline and Cefazedone were administered i.v. as injection of 2 minutes duration and as infusion of 30 minutes duration. The concentrations in blood plasma and the excretion with the urine were similar for both substances and differed only with regard to their levels during the first 60 minutes, depending on the mode of administration.

Cefazolin↗
PubMed1980

Haemodynamic effects of guanfacine.

1. The haemodynamic mechanism of action of guanfacine 4 mg intravenously was investigated in resting conditions and during exercise for up to 20 h after administration of the drug. Cardiac output and pulmonary arterial pressure were determined by the Swan-Ganz thermodilution method. Blood pressure was measured directly. 2. During and immediately after intravenous administration of guanfacine, blood pressure peripheral resistance and pulmonary arterial pressure increased (in keeping with an alpha-sympathomimetic effect of the compound), whereas heart rate and cardiac output decreased. 3. Subsequently blood pressure fell as a result of a decrease in cardiac output. From the third hour peripheral resistance decreased, whereas cardiac output increased again, sometimes exceeding the control value. 4. During exercise blood pressure was reduced from the third hour after administration, as in resting conditions, as a result of the reduction in peripheral resistance. 5. In resting conditions guanfacine reduced heart rate at the beginning and during the whole course after administration of the drug. 6. Side-effects noted included fatigue, drowsiness and bradycardia.

Antihypertensive Agents↗