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Biomedical subjects

J Koch-Weser

Publications and source records attributed to J Koch-Weser.

At least 73 records · Page 4Linked to original sources
PubMed1976

[Drug interactions in cardiovascular therapy].

Cardiovascular therapy frequently requires simultaneous administration of several drugs. These drugs may interact pharmacokinetically or pharmacodynamically, and most drug interactions are therapeutically useful. The clinical importance of adverse drug interactions is often overestimated; they are almost always predictable and preventable, if their mechanisms are understood and the drug dosages appropriately modified. Coumarin anticoagulants and cardiac glycosides are involved in the most serious interactions. Diuretics, antiarrhythmic drugs, sympatholytics, sympathomimetics and monoamine oxidase blockers also interact in clinically significant fashion with other drugs.

Antidepressive Agents↗
PubMed1976

Pharmacokinetic approach to the clinical use of lidocaine intravenously.

The time course of lidocaine plasma concentrations following various modes of administration were predicted by computer. Initiating therapy with a single intravenous bolus dose was unsatisfactory; plasma levels during the first hour were potentially toxic after a 200-mg bolus and subtherapeutic after a 50- to 100-mg bolus. After two bolus doses of 100 mg, separated by 20 to 30 minutes, or a rapid loading infusion over 15 to 60 minutes, therapeutic concentrations were achieved and maintained. Pharmacokinetic principles can be of value in devising rational approaches to lidocaine dosage.

Arrhythmias, Cardiac↗
PubMed1976

Diazoxide.

Explore the source record for details and available documents.

Blood Pressure↗
PubMed1976

Accidental poisoning with psychotropic drugs in children.

Seventy-seven (0.24%) of 32,005 admissions to the Massachusetts General Hospital pediatric service during the period 1962 to 1973 were due to accidental poisoning. In 27 cases, mostly involving children less than 6 years of age, psychotropic drugs were implicated. These included sedative-hypnotics in six cases, phenytoin in two, major tranquilizers in five, antidepressants in three, stimulants or hallucinogens in three, and drug mixtures in eight. Toxicologic analyses contributed little to diagnosis and initial management. Except for one child who ingested ferrous sulfate, no patient was seriously intoxicated, and all recovered rapidly without sequelae. Although referral of serious poisoning cases to another hospital may have biased the results, the findings suggest that accidental psychotropic drug poisoning is not a major source of childhood morbidity.

Amobarbital↗
PubMed1976

Influence of magnesium and aluminum hydroxide mixture on chlordiazepoxide absorption.

Ten healthy male subjects ingested 25 mg of chlordiazepoxide hydrochloride (Librium) with 100 ml of water or with 100 ml of magnesium and aluminum hydroxide (Maalox) in a single-dose crossover study. Multiple venous blood samples drawn during the first 24 hr after each dose were assayed for concentrations of chlordiazepoxide and its major metabolite, desmethylchlordiazepoxide. The antacid prolonged the mean chlordiazepoxide absorption half-time from 11 to 24 min, and in 6 of 10 subjects delayed achievement of the peak blood concentration by from 0.5 to 3.0 hrs. The formation of desmethylclordiazepoxide was also slowed. The areas under the 24 hr blood concentration curve for chlordiazepoxide and for its metabolite were not influenced by the antacid. The apparent elimination half-life of chlordiazepoxide (8.4 and 8.2 hr) was not significantly affected. Administration of chlordiazepoxide with antacid reduces the rate of its absorption but does not alter the completeness of absorption or the apparent rate of elimination.

Adult↗
PubMed1976

Kinetics of high-dose intravenous morphine in cardiac surgery patients.

Ten patients received 1.0 mg/kg of morphine sulfate by constant-rate intravenous infusion at 5 mg/min over 9 to 27 min. Multiple arterial blood samples were drawn during the first 30 to 151 min after termination of the infusion, prior to institution of cardiopulmonary bypass. Postinfusion plasma concentrations were fitted by computer to biexponential functions consistent with a 2-compartment open pharmacokinetic model. Mean (+/- SE) pharmacokinetic parameters were: volume of central compartment, 0.09 +/- 0.03 L/kg; total apparent volume of distribution, 1.02 +/- 0.09 L/kg; distribution T 1/2, 0.90 +/- 0.09 min; apparent elimination T 1/2, 137 +/- 14 min; total clearance, 378 +/- 63 ml/min. Thus distribution of morphine is very rapid, but the apparent volume of distribution is only slightly larger than body weight, suggesting limited tissue uptake. Since apparent elimination T 1/2s are similar to those reported after smaller doses, evidence of saturable or capacity-linked elimination is lacking. Total clearances, representing mainly hepatic clearance, averaged about 25% of hepatic blood flow, suggesting clinically important first-pass metabolism of oral morphine.

Adult↗
PubMed1976

Plasma and cerebrospinal fluid concentrations of chlordiazepoxide and its metabolites in surgical patients.

Thirty otherwise healthy patients received a 100-mg oral dose of chlordiazepoxide HCl just prior to surgical procedures using spinal anesthesia. Fourteen of these patients had also received 100 mg on the night before surgery. Simultaneous samples of venous blood and cerebrospinal fluid (CSF) were taken immediately prior to injection of spinal anesthesia and were assayed for concentrations of chlordiazepoxide (CDX) and its major metabolite, desmethylchlordiazepoxide. Plasma concentrations of CDX ranged from 2.32 to 13.34 mug/ml. Simultaneous CSF concentrations were considerably lower, ranging from 0.04 to 0.34 mug/ml. Equilibration of CDX between plasma and the lumbar sampling site appeared to be complete within 2 hr of the most recent dose. After attainment of distribution equilibrium, simultaneous plasma and CSF concentrations of CDX were hightly correlated (r = 0.76), with a mean CSF-plasma concentrations ratio of only 0.043 (range; 0.02 to 0.06). The limited passage of CDX into human CSF is probably due to extensive binding to plasma protein. Assuming that transfer of CDX from plasma to CSF is governed by passive diffusion, the extent of plasma protein binding of CDX in healthy individuals averages about 96%.

Adult↗
PubMed1976

Variability of 24-hour urinary creatinine excretion by normal subjects.

Creatinine excretion was studied in eight healthy males who collected 54 to 97 24-hour urine specimens. Significant differences among subjects in mean creatinine excretion were only partly explained by differences in body weight and surface area. Considerable daily within-subject variation in creatinine excretion during normal activity was found. Standard deviations were from 10.5 to 14.4 per cent of the mean, and ranges varied from 50 to 79 per cent of the mean. Day-to-day variation appeared to be time dependent rather than entirely random, and could not be explained by unreliability of the assay technique or by incomplete collections. Creatinine excretion values were normally distributed in seven of eight subjects. Individual variation from day to day limits the value of urinary creatinine excretion as an index of the completeness of 24-hour urine collections.

Adult↗
PubMed1976

Clinical use and toxicity of intravenous lidocaine. A report from the Boston Collaborative Drug Surveillance Program.

The clinical use and toxicity of intravenous lidocaine were surveyed in 750 hospitalized medical patients who received the drug for the treatment of cardiac arrhythmias. The majority of these patients were older than 60 years and most had diagnoses of cardiovascular disease. Lidocaine therapy was started within 48 hours of admission in 77 per cent of cases. Adverse reactions to lidocaine were reported in 6.3 per cent of patients, but only one in four reactions was considered life-threatening. Central nervous system disturbances and cardiovascular complications were the most common untoward effects. All but two adverse reactions occurred within the first 5 days of treatment. Adverse reactions were more common in elderly individuals, in those who died, and in those with long hospitalizations. Diagnoses of acute myocardial infarction or congestive heart failure, and low body weight were also associated with a higher frequency of unwanted effects. Serious adverse reactions to intravenous lidocaine were relatively uncommon. Patients with serious underlying disease or with diminished hepatic clearance of lidocaine appear to be predisposed to adverse effects from this drug.

Aged↗
PubMed1976

Antiarrhythmic drugs for ischemic heart disease.

Therapy with antiarrhythmic drugs may offer the best immediate hope for reducing the large number of deaths due to arrhythmias among patients with ischemic heart disease (IHD). For the prevention of sudden death from ventricular fibrillation, chronic use of these drugs is reasonable in high-risk ambulatory IHD patients, in any patient in whom acute myocardial infarction (MI) is suspected, and in some patients hospitalized for acute MI. However, the effectiveness and possible risks of administering antiarrhythmic drugs in these settings remain essentially unknown. The selection of IHD patients who will benefit most from prophylactic antiarrhythmic drug therapy, the best times for starting and stopping this therapy, and the choice of drug cannot yet be guided by controlled clinical experience. Carefully controlled prospective studies of the beneficial and untoward effects of different drugs in IHD patients are urgently required to provide better guidelines for the clinical use of these potentially life-saving drugs.

Acute Disease↗