PubMed · 4839033
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I Chanarin, D A Waters. 1974. Failed Schilling tests.. https://doi.org/10.1111/j.1600-0609.1974.tb00205.x
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Sequential cyclosporine pharmacokinetic assessments were performed at four centres within the context of a double-blind, multicenter clinical trial comparing the safety and tolerability of the conventional formulation with cyclosporine for microemulsion in de novo renal transplant patients. The initial average daily oral dose was 9.3 mg/kg given in two divided doses every 12 hr with subsequent dose reductions individually titrated to maintain trough concentrations within the target therapeutic range. Pharmacokinetic profiles were assessed at week 2, once between weeks 4-6, and at week 12 in 12 patients on the conventional formulation and 9 patients on the microemulsion. Over the study duration, cyclosporine daily doses were comparable in both study arms and were reduced in parallel from 9.2 to 6.9 to 4.7 mg/kg/day at the three successive pharmacokinetic visits. Dose-normalized peak and area-under-the-curve (AUC) increased between the week 2 and week 4-6 assessments for both formulations. Thereafter, these parameters continued to increase for the conventional formulation but exhibited a high degree of within-in patient stability for the microemulsion between week 4-6 and week 12. Between-formulation comparisons indicated that the rate and extent of cyclosporine absorption from the microemulsion were significantly higher over the study duration. Specifically, at week 2, 4-6 and 12, dose-normalized AUC was 49%, 63%, and 32% higher for the microemulsion. Intrasubject coefficients of variability for pharmacokinetic parameters of the conventional formulation ranged from 26.3% to 68.2%. Corresponding values for the microemulsion were reduced by approximately half, ranging from 13.1% to 38.7%. The correlation between predose trough concentration and AUC was stronger for the microemulsion (r(2)0.819 vs. 0.635) over the full range of systemic exposures attained throughout the study. These results provide initial evidence that, as doses are reduced with time posttransplant, the cyclosporine dose-exposure relationship from the microemulsion may stabilize earlier than that from the conventional formulation, allowing increased pharmacokinetic control over cyclosporine use in this critical posttransplant period.
Vesnarinone is a novel oral agent that improves survival and symptoms of patients with dilated cardiomyopathy. Although it is thought to have positive inotropic effects, clinical data supporting this mechanism in patients with severe heart failure remain scant. The present study tested whether 3 months of oral vesnarinone therapy increases the inotropic state and whether this response is dose dependent. Twenty-one patients with dilated cardiomyopathy (New York Heart Association class III to IV) were randomized to 30 mg/day (n = 11) or to 60 mg/day (n = 10) of vesnarinone. Cardiac function was assessed before and after therapy by radionuclide ventriculography to measure left ventricular volume and flow and by noninvasive measurement of the central aortic pressure wave. The inotropic effect of vesnarinone was assessed by a recently validated index equal to the ratio of left ventricular maximal ventricular power divided by the square of end-diastolic volume (PWRmax/ EDV2). This ratio is sensitive to inotropic change but is minimally altered by chamber loading. After 3 months of 60 mg/day therapy, PWRmax/EDV2 increased by 28 +/- 32%. Ejection fraction and cardiac output also increased by 21 +/- 14% and 14 +/- 14%, respectively, and arterial load decreased by 10.5 +/- 12.4% (all p < 0.005). End-systolic volume also declined by 7 +/- 10%, suggesting reverse remodeling. These changes were smaller and none achieved statistical significance at the 30 mg/day dose (e.g., 14.2 +/- 35.4% for PWRmax/ EDV2). Heart rate was unchanged with either dose. Thus, chronic vesnarinone treatment dose modestly raises the inotropic state and lowers afterload in patients with dilated cardiomyopathy in a dose-dependent fashion.
The efficacy and safety of a single oral dose of 150-mg pilsicainide, a new class Ic antiarrhythmic drug, in converting recent-onset atrial fibrillation to sinus rhythm were evaluated in 75 patients (51 men, 24 women; age 23 to 74 years). Conversion to sinus rhythm was achieved within 90 minutes in 45% of patients given pilsicainide and in 8.6% of those on placebo (p < 0.01), with no major adverse effects.