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Biomedical subjects

A L Goldfarb

Publications and source records attributed to A L Goldfarb.

7 recordsLinked to original sources
PubMed1992

Effect of cimetidine administration on the pharmacokinetics of pirmenol.

The potential for a drug-drug interaction between pirmenol, an extensively metabolized antiarrhythmic agent, and cimetidine, an inhibitor of hepatic drug-metabolizing enzymes, was evaluated in eight healthy adults. A single 150-mg oral dose of pirmenol was administered on study days 1 and 8 and oral cimetidine, 300-mg QID, was administered on study days 4 through 11. Plasma and urine samples were collected after each pirmenol dose for determination of pirmenol concentration. Mean pirmenol concentration-time curves and pharmacokinetic parameters, including elimination rate constant, were not significantly altered by concomitant administration of cimetidine.

Administration, Oral↗
PubMed1979

Clinical pharmacokinetics of procainamide infusions in relation to acetylator phenotype.

The pharmacokinetics of procainamide was determined in 21 lidocaine-resistant patients who received the drug according to a pharmacokinetically designed double-infusion technique. Thirteen patients were phenotyped as slow acetylators, seven as fast, and one as intermediate. The total body clearances (ClT) of PA in slow and fast acetylators were 22.6 and 34.8 liters/hr, respectively. The fraction of PA cleared by the formation of NAPA in the corresponding acetylator group was 0.2 and 0.4. Renal impairment affected the pharmacokinetics of PA more profoundly as the ClT's of PA in patients with and without renal impairment were 17.9 and 31.2 liters/hr, respectively. None of the calculated volumes of distribution was affected by acetylator phenotype or renal impairment. These data identify the contribution of at least two of the major factors accounting for variability in PA disposition in patients undergoing therapy.

Acetylation↗
PubMed1979

Safety and efficacy of procainamide infusions.

Thirty-four patients who were resistant to conventional doses of lidocaine received procainamide intravenously according to a pharmacokinetically designed two infusion technique. A mean peak serum concentration of 7.1 mg/liter was achieved with an average loading dose of 989 mg administered over 1 hour. A mean steady state serum concentration of procainamide of 6.5 mg/liter was achieved with a mean dose of 64.4 mg/kg body weight for the first 24 hours of treatment. Dose, renal impairment, the degree of congestive heart failure and acetylator status influenced the steady state serum concentration of procainamide. Dangerous ventricular arrhythmias were abolished in 74% of the patients at a steady state level of 6.9 +/- 3.7 mg/liter (mean +/- standard deviation). Nonresponders to procainamide had a mean steady state serum concentration of procainamide of 4.2 +/- 2.1 mg/liter (P less than 0.05). Systolic and diastolic blood pressures decreased moderately (10 and 8%, respectively), and heart rate decreased 11%. The infusion was interrupted in one patient because of hypotension. The duration of electrocardiographic conduction intervals was increased slightly in some patients. It is concluded that procainamide administered by this two infusion method is effective and well tolerated by most patients.

Arrhythmias, Cardiac↗
PubMed1978

Pharmacokinetic approach to intravenous procainamide therapy.

A pharmacokinetic approach was employed to design a dosing regimen for the i.v. use of procainamide (PA) which consisted of a loading infusion given over one hour followed by a maintenance infusion. Therapeutic serum concentrations of PA were achieved in less than 15 min, and toxic serum concentrations were avoided in 12 patients. A mean maximum serum concentration of PA of 5.78 mg/l was obtained with a loading infusion of 16.6 mg/min PA HCl. An average steady-state serum concentration of PA of 5.05 mg/l was obtained with a mean maintenance infusion of 222 mg/hour PA HCl. The total body clearance of PA in slow and fast acetylators averaged 31 and 43 l/h respectively. Use of PA in cardiac patients by i. v. infusion can be safe and effective therapy.

Acetylation↗
PubMed1976

Unusual electrocardiographic changes in spontaneous pneumothorax.

A young woman with spontaneous left pneumothorax had a phasic voltage alternation of her electrocardiogram that resolved with expansion of the lung. Likely explanations for this phenomenon are a respiratory dependent change in cardiac anatomy and a change in the volume conductor with respiration.

Adult↗
PubMed1975

pH-dependent secretion of procainamide into saliva.

The relationship between serum and stimulated, mixed saliva concentrations of procainamide was determined in 12 chronically medicated patients. Samples were obtained at times chosen to approximate the maximum and minimum serum concentrations of the drug during a dosing interval. Marked intersubject variability was found in the ratio of saliva to serum concentration of the drug (0.27-8.93). There was no correlation between the dose (milligrams per kilogram per day) and the minimum serum or saliva concentration of procainamide. Saliva pH ranged from 6.3 to 8.0 in eight subjects. The ratio of saliva to serum concentration of procainamide increased with decreasing pH. This result can be largely explained by the pH-dependent ionization and distribution of procainamide, a weak base.

Humans↗