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Biomedical subjects

W R Bartle

Publications and source records attributed to W R Bartle.

28 records · Page 2Linked to original sources
PubMed1983

Dose-dependent effect of cimetidine on phenytoin kinetics.

Eight normal subjects were given 250 mg intravenous phenytoin alone and with 3-day regimens of oral cimetidine, 400 mg at bedtime, 1200 mg a day, and 2400 mg a day in a randomized crossover fashion. Plasma samples for phenytoin and cimetidine, and urinary concentrations for phenytoin and 5-(4-hydroxyphenyl)-5-phenylhydantoin (HPPH) were measured by HPLC. All cimetidine regimens decreased phenytoin clearance, and there was no difference between the 400-mg bedtime dose and the 1200-mg a day regimens. There was, however, a difference between the 400-mg and 1200-mg and the 2400-mg regimens. There was no linear correlation between steady state cimetidine plasma concentrations and the decrease in phenytoin clearance. Urinary HPPH/phenytoin ratios decreased with all cimetidine treatments, but the differences were not significant. Phenytoin toxicity may result when cimetidine is added to existing regimens of this anticonvulsant.

Adult↗
PubMed1979

Effect of neomycin on the bioavailability of spironolactone: a single-dose study.

The effect of oral neomycin sulfate on the bioavailability of oral spironolactone in humans was studied. A 100-mg spironolactone tablet was administered alone or with two 500-mg neomycin sulfate tablets to 12 healthy, fasting men in a randomized crossover fashion. Levels of canrenone (an active spironolactone metabolite) in plasma and urine samples collected for 32 and 48 hours after dosing, respectively, were measured fluorimetrically. Neomycin significantly decreased the peak plasma canrenone concentration, significantly increased the time to reach peak concentration of canrenone, and significantly decreased the urinary excretion of canrenone over the first four hours (p less than 0.05). There were no significant differences between treatment groups in elimination half-life, area under the plasma curves or 48-hour urinary excretion of canrenone. Single doses of neomycin appear to delay the rate but not reduce the extent of spironolactone absorption. Thus, neomycin may not interfere with the clinical efficacy of spironolactone.

Adult↗
PubMed1977

Antibiotic-associated pseudomembranous colitis.

Two cases of pseudomembranous colitis, one associated with administration of ampicillin and the other associated with administration of ampicillin and trimethoprim-sulfamethoxazole, are reported. Both patients presented with diarrhea, abdominal pain, fever and an elevated leukocyte count. Pseudomembranous colitis was diagnosed by sigmoidoscopy and biopsy. Both patients recovered with conservative management.

Ampicillin↗
PubMed1976

Tartrazine-containing drugs.

Pharmaceutical manufacturers producing or distributing drugs in Canada were surveyed between December 1974 and March 1975 to determine which of their products contained tartrazine, a pyrazole aniline dye. A list of some 580 drug products of the 156 manufacturers who responded is presented for aid in managing the tartrazine-sensitive patients.

Aniline Compounds↗
PubMedDate not supplied

Effect of low-dose cimetidine on theophylline metabolism.

The effect of low doses of cimetidine on theophylline clearance and metabolism was studied. In a randomized, crossover study, 10 healthy men received oxtriphylline alone or with cimetidine. Oxtriphylline 200 mg (equivalent to theophylline 135 mg) was given orally every eight hours for 10 doses. Cimetidine 300 mg was given orally at bedtime for four days, beginning the same day as oxtriphylline treatment. At least 10 days separated study periods. In each study period, blood samples for plasma theophylline determinations were drawn 24 hours before the last dose of oxtriphylline, at the time of the last dose, and periodically up to 32 hours after the last dose. A 24-hour urine collection for quantification of theophylline and metabolite excretion was started at the time of the last oxtriphylline dose. Plasma theophylline clearance decreased significantly by a mean of 12.2% during cimetidine treatment. Area under the curve showed a significant mean increase of 17.4%. Increases in clearance and area under the curve values occurred in 9 of 10 subjects. In 6 of 10 subjects who had increases in theophylline trough concentrations, the mean increase was 28.2%; when all 10 subjects were considered, however, the mean increase was 10.3%, which was not significant. No significant differences in the urinary recoveries of theophylline or its metabolites were noted between study periods. Because of the decreases in theophylline clearance produced by low doses of cimetidine in this study, clinicians should monitor for potential theophylline toxicity in patients who receive these drugs concomitantly.

Adult↗