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Biomedical subjects

J O Covinsky

Publications and source records attributed to J O Covinsky.

23 records · Page 2Linked to original sources

Comparative plasma concentrations of quinidine following administration of one intramuscular and three oral formulations to 13 human subjects.

A GLC method, based on flame-ionization detection, was developed for the assay of methotrimeprazine and its sulfoxide in plasma. For a 6-ml aliquot, the sensitivity was 2-3 ng/ml for the unchanged drug and 4-5 ng/ml for the sulfoxide. The coefficient of variation, calculated from duplicate analyses of plasma samples, was 8-15% for concentrations between 10 and 100 ng/ml. Patients treated with orally administered methotrimeprazine had higher plasma levels of the sulfoxide than of unmetabolized drug. The method also was applied to the analysis of promazine and chlorpromazine in patient plasma.

Administration, Oral↗

Relative bioavailability of quinidine gluconate and quinidine sulfate in healthy volunteers.

A comparison of the bioavailability of quinidine sulfate to quinidine gluconate tablets in a single-dose randomized cross-over design with 20 healthy volunteers shows that the sulfate salt is more rapidly absorbed and provides significantly greater peak concentrations 1 hour after administration as compared to the peak levels achieved with the gluconate salt at approximately 5 hours after administration. When adjusted for the actual amount of quinidine contained in each tablet, there was no significant difference in the amount of quinidine bioavailable. Since quinidine gluconate absorption is significantly slower than quinidine sulfate, a combination of the two dosage forms may be utilized in providing the loading dose. Based on the computer modeling and the clinical data accumulated by this laboratory (unpublished) over the past four years, quinidine gluconate, in the dosage form utilized in this study, provides more constant blood levels with smaller differences between the Cpmax and Cpmin than the sulfate when administered every 6 or 8 hours. Further controlled clinical studies are needed to confirm these observations in patients.

Adult↗

The impact of the docent clinical pharmacist on treatment of streptococcal pneumonia.

This two-phase retrospective study was designed to evaluate the impact of the clinical pharmacist on prescribing practice of physicians in an internal medicine service. Streptococcal (pneumococcal) pneumonia was chosen as the model disease state. The drug of choice was used more frequently and there was a statistically significant difference in raw cost of antibiotic, total cost for antibiotic administration, daily raw cost for antibiotics; total raw cost for antibiotic administration, and patient charges when physicians were exposed to the clinical pharmacists' influence.

Anti-Bacterial Agents↗

Oxprenolol hydrochloride: pharmacology, pharmacokinetics, adverse effects and clinical efficacy.

Oxprenolol is a nonselective beta-adrenergic blocking agent that also possesses intrinsic sympathomimetic activity (ISA) and membrane stabilizing effects. Oxprenolol undergoes first pass metabolism with only 30% of an oral dose reaching the systemic circulation. The drug is approximately 80% protein bound and is eliminated primarily by glucuronidation in the liver. Less than 4% of oxprenolol is excreted unchanged in the urine. Oxprenolol may reduce the heart rate and prolong the effective and functional atrioventricular nodal refractory period. Oxprenolol has less negative inotropic and chronotropic effects than propranolol. Plasma renin activity is reduced; however, changes in plasma aldosterone level are not significant. Long term metabolic effects require further study. Oxprenolol appears to be comparable to other beta blockers in the treatment of hypertension and angina pectoris with no additional adverse reactions. If its partial agonist effect proves useful, it may have an advantage over other agents in treating patients with borderline cardiac reserve. Because of limited data, the use of oxprenolol for the treatment of arrhythmias, migraine, thyrotoxicosis, anxiety, and glaucoma cannot be recommended at this time.

Airway Resistance↗