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Biomedical subjects

R L Yost

Publications and source records attributed to R L Yost.

28 records · Page 2Linked to original sources
PubMed1978

Confirmation of a computer-derived nomogram to predict gentamicin serum concentrations in postsurgical patients.

The applicability of a previously reported nomogram to predict serum gentamicin levels in postsurgical patients was investigated. Seventeen patients accounting for 20 courses of gentamicin were studied. A total of 72 peak serum gentamicin levels were measured by a microbiological assay and compared with predicted serum levels determined by the dosing nomogram. Eighty-five percent of the measured peak gentamicin serum levels agreed with nomogram-predicted levels. This figure was reduced to 65% when certain unforeseen factors (i.e., patient interference with intravenous lines, dosage miscalculation and extra routes of gentamicin elimination) were identified. The nomogram is a particularly useful tool for the clinician to whom serum gentamicin levels are unavailable and who needs a method to predict serum gentamicin concentration based upon a given dosage.

Adult↗
PubMed1978

Survey of clinical pharmaceutical services in Florida hospitals.

A survey of clinical pharmaceutical services in Florida hospitals is described. Questionnaires were mailed to the pharmacy departments of 210 hospitals containing 50 or more beds; 172 (82%) responded. Data were collected concerning the extent and types of clinical services provided; the reasons for not implementing the services were also obtained. Twenty (12%) hospitals employed a full-time clinical pharmacist. Inservice drug education, formalized drug information, cardiopulmonary resuscitation and patient medication histories were provided by 78%, 47%, 19% and 6% of the hospitals, respectively. Hospitals with a total or partial unit dose drug distribution system seemed more likely to provide clinical services than those with other types of distribution systems. Hospitals employing a clinical pharmacist were engaged in a wider range of clinical services and provided these services to a larger portion of their patient population. The reason most frequently cited for not implementing clinical services was inadequate staff.

Florida↗
PubMed1977

Convulsions associated with sodium cefazolin: a case report.

Our patient was severely injured, and had a prolonged period of hypotension. After operation she received moderate doses of cefazolin, intravenously, in the face of acute renal failure. Seizures associated with a serum cefazolin level of 455 mg/ml were observed. Although a cause and effect relationship between high cefazolin levels and neurotoxicity cannot be proven conclusively, the implication of this relationship exists. The clinician should be aware of the potential neurotoxicity of this commonly used drug. The importance of adjusting the dose in patients with renal failure is re-emphasized.

Acute Kidney Injury↗
PubMedDate not supplied

Surgically affected sulfisoxazole pharmacokinetics in the morbidly obese.

Intestinal bypass surgery in 4 morbidly obese female (110-150 kg) had no permanent effect on the rate or amount of sulfisoxazole absorption. The loss of weight up to 44 per cent within an individual over a year's time had no significant effect on the apparent volumes of distribution or other pharmacokinetic parameters of sulfisoxazole and its N4-acetylsulfisoxazole metabolite. Dosing of this drug on a mg kg-1 basis is contraindicated. Renal clearances of sulfisoxazole were reasonably constant within a study but those of the N4-acetylsulfisoxazole decreased with time. Integrated pharmacokinetic models were applied to plasma and urine data to estimate the metabolic clearance of sulfisoxazole and the apparent volume of distribution of the N4-acetylsulfisoxazole. Sulfisoxazole solution is absorbed readily by primarily a zero order process after a short lag period, indicative of rate-determining gastric emptying. The classical Bratton-Marshall assays were compared with an HPLC assay of both drug and metabolite. There was greater confidence in plasma levels of the metabolite from the HPLC method.

Adult↗
PubMedDate not supplied

Parenteral nutrition utilization: evaluation of an educational protocol and consult service.

A two part study was undertaken to evaluate the effectiveness of an educational protocol and consult service on parenteral nutrition (PN) utilization. Forty-one patient admissions were evaluated retrospectively and nine prospectively. Average length of hospital stay and number of days on PN were decreased significantly (p less than .05). Frequency of adverse effects were also decreased significantly (p less than .05). A positive trend toward selection of patients for enteral rather than PN was evidenced. Utilization of already available manpower and financial resources by this modified approach should contribute toward reducing costs and hazards of PN therapy, particularly for smaller hospitals with both limited requirements and resources, as well as for teaching institutions.

Adult↗
PubMedDate not supplied

Effect of antacid on bioavailability of a sustained-release theophylline preparation.

The effect of coadministration of an antacid on bioavailability of a sustained-release theophylline tablet preparation (Theo-Dur) was studied by crossover comparison in five young, healthy, nonsmoking volunteers. Water 90 ml, or "high potency" aluminum-magnesium hydroxide antacid (Mylanta II) 10 ml and water 80 ml were administered concurrently with sustained-release theophylline 600 mg. Eleven blood samples were collected over the next 24 hours. Serum was analyzed with high pressure liquid chromatography technique to determine theophylline concentration. Peak serum concentration (Cmax) and time to peak concentration (tmax) were determined, and area under the 24-hour serum concentration-time curve (AUC) was calculated by the trapezoidal rule for each subject at each study interval. The Student's paired t-test was used to compare Cmax, tmax, and AUC for both treatments. A uniform difference was found between groups in Cmax. Cmax was higher in subjects when treated with the antacid (10.45 +/- 3.03 vs. 8.30 +/- 2.90 micrograms/ml, p less than 0.05) than when given theophylline alone. The mean tmax for the two treatments did not differ (10.4 +/- 1.67 h-combination vs. 10.8 +/- 1.1 h-theophylline, p greater than 0.05). Likewise, mean AUC was unchanged by the coadministration of antacid (140.65 +/- 41.6 micrograms/ml.h--combination vs. 155.13 +/- 46.6 micrograms/h--theophylline, p greater than 0.05). The use of a high-potency antacid product did not decrease the extent of theophylline absorption from this sustained-release product, but did increase Cmax and, presumably, rate of absorption. High-potency aluminum-magnesium antacids can probably be used in combination with this sustained-release theophylline tablet without detriment to therapy.

Adult↗
PubMedDate not supplied

Ceftazidime review.

The chemistry, in vitro activity, adverse effects, and clinical indications for the new third-generation cephalosporin, ceftazidime, are reviewed. Ceftazidime appears to have a unique place among the third-generation agents in the treatment of some infectious processes caused by Pseudomonas aeruginosa. It does not demonstrate superiority to other third-generation drugs against Enterobacteriaceae, aerobic gram-positive cocci, or anaerobes. It is eliminated renally and is similar to ceftizoxime, cefoperazone, and moxalactam in half-life. Ceftazidime shares the safety profile of most of the cephalosporins, and has not been shown to have an effect on prothrombin or produce the disulfuram reaction seen with moxalactam and cefoperazone. Specific indications for its use are discussed.

Bacteria, Anaerobic↗
PubMedDate not supplied

Effect of dose and ointment application technique on nitroglycerin plasma concentrations.

Each of ten non-smoking, healthy male volunteers between the ages of 20 and 30 and within 10% of their ideal body weight received four nitroglycerin ointment (NTG-O) treatments: 1/2" NTG-O over 3.94 in2 and 7.88 in2, and 1" NTG-O over 3.94 in2 and 7.88 in2 in a randomized order. Eleven blood samples and 22 determinations of heart rate and blood pressure were obtained over each 6-hour study period. Nitroglycerin plasma concentrations were determined by gas-liquid chromatography with electron capture detection. Area under the nitroglycerin plasma concentration-time curve (AUC), peak plasma concentration (Cmax), and time to peak concentration (Tmax) were determined for each study. Cmax and AUC values were corrected for the actual dose applied. Differences between AUC, Cmax and Tmax were tested using repeated measures analysis of variance. Change in surface area had no statistically significant effect on AUC, Cmax and Tmax. Mean AUC for the 1/2" and 1" doses differed (648 vs 2003 ng.ml-1 min, p = 0.016), as did Cmax (4.6 vs 12.4 ng.ml-1, p = 0.022); however, there was no correlation between individual doses and AUCs. Generally, NTG plasma concentrations within the proposed therapeutic range of 1.2-11.1 ng.ml-1 were detectable throughout each study interval. These data suggest that continuous absorption occurred throughout the 6-hour dosing interval, that a trend toward increased AUC and Cmax occurred with the larger surface area, and that, in general, doubling the dose of NTG-O doubles the AUC.

Adult↗