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Biomedical subjects

K W Kolb

Publications and source records attributed to K W Kolb.

7 recordsLinked to original sources
PubMed1989

The effect of everyday exercise on steady state digoxin concentrations.

The purpose of this study was to evaluate the effect of 1 hour of everyday exercise (walking at patient's own pace) on serum digoxin concentrations. Nine white male subjects (ages 58-74) who had been taking the same digoxin dose for greater than 1 month participated. There were three continuous phases: 1 hour of rest, 1 hour of exercise, and a final hour of rest. Serum digoxin concentrations were drawn every 20 minutes. During the first rest period, serum digoxin concentrations rose 30% from the first concentration drawn in the study. After 1 hour of exercise, serum digoxin concentrations fell 26.8% from the last concentration of the first rest period. At the end of the second hour of rest, serum digoxin concentrations increased by 36.6% from the last concentration. Repeated measures analysis of variance demonstrated a significant (P less than .01) change in serum digoxin concentrations. Significant (P less than .01) differences were found between sampling times 0 and 60, 60 and 80, 60 and 100, 60 and 120 and 180 minutes using a paired t-test with Bonferroni correction. A weak correlation (r = 0.74, r2 = 0.55) between percent change in concentrations and age during the exercise phase was found, but there was no correlation between the percent change in concentrations and age during the two immobilization phases. Because significant changes in concentrations occurred during each phase of the study, we conclude that the influence of everyday exercise should be taken into account when interpreting serum digoxin concentrations.(ABSTRACT TRUNCATED AT 250 WORDS)

Age Factors↗
PubMed1984

Effect of cimetidine on quinidine clearance.

Cimetidine has been reported to inhibit the hepatic metabolism of numerous drugs. Theoretically cimetidine could inhibit the metabolism of quinidine. This study was undertaken to determine the effect of cimetidine on quinidine plasma concentrations. Nine healthy volunteers were entered into the matched-pairs study. Baseline quinidine pharmacokinetic parameters were determined after a single oral 400-mg dose. Study parameters were determined after 3 days of cimetidine 300 mg p.o. q.i.d., when 400 mg quinidine was again administered. Cimetidine increased the area under the time-concentration curve (14.5%, p less than 0.01), decreased the total body clearance (24.9%, p less than 0.05), and prolonged the half-life (22.6%, p less than 0.05) of quinidine in this study. There was no change in peak quinidine concentrations or time to peak. These data document an interaction between cimetidine and quinidine. The clinical importance of this interaction should be greatest in patients with impaired liver function, patients with preexisting near-toxic plasma concentrations of quinidine, and the elderly. Patients placed on cimetidine and quinidine should be monitored closely for signs and symptoms of quinidine toxicity.

Adult↗