A prospective, parallel, double-blind comparison of iodixanol and iohexol in extremity phlebography.

RATIONALE AND OBJECTIVES: A two-center, prospective, double-blind study was conducted to compare the performance parameters (efficacy, safety, and injection-associated discomfort) of iohexol with those of the new, isosmolar contrast medium iodixanol in extremity phlebography. METHODS: Ninety-nine patients from two centers, for whom venography was clinically indicated, were blindly randomized into two groups, iohexol at 300 mg I/ml (IOH 300) or iodixanol at 270 mg I/ml (IOD-270). Patient vital signs and reports of adverse events were recorded for a minimum of 1 hr and monitored until the outcome was known. Any discomfort associated with the injection was also recorded. Laboratory measures included urinalysis, creatinine levels in serum and blood urea nitrogen. RESULTS: Both contrast media provided good or excellent visualization in nearly all patients (100% of patients in the IOD-270 group and 96% in the IOH-300 group). The incidence of adverse reactions was low in both groups (8.5% in the IOD-270 group and 10% in the IOH-300 group). Injection associated discomfort lasting less than 4 min occurred in nine patients, four in the IOD-270 group and five in the IOH-300 group. Although clinically relevant changes in vital signs occurred in more than half the patients, most were judged to be anxiety related. Review of laboratory data revealed no evidence of toxicity for either agent. There was no statistically significant difference between the two agents with regard to any of these observed parameters. CONCLUSION: The data support the conclusion that both IOD-270 and IOH-300 are safe and effective agents when used for adult phlebography and are associated with little injection-site discomfort.

Lack of effect of vitamin B-6 supplementation on the lipoprotein profile of post-menopausal chronic hemodialysis patients.

This study was designed to analyze the effect of vitamin B-6 supplementation on the lipoprotein profile of chronic hemodialysis patients. Individuals on chronic hemodialysis experience an acceleration of atherosclerosis, which is often accompanied by abnormal lipid metabolism. Although total plasma cholesterol is usually normal, high-density-lipoprotein (HDL) cholesterol is often low. Recently, it has been suggested that the development of atherosclerotic lesions in chronic hemodialysis patients may be the result of a decreased plasma concentration of pyridoxal 5'-phosphate (PLP) and concomitant alterations in plasma amino acid and/or lipoprotein profiles. All subjects in this study were supplemented with 0.97 mmol (200 mg) pyridoxine hydrochloride per day for 28 days; then, concentrations of PLP, total cholesterol, and lipoprotein cholesterol fractions were determined in the plasma. No significant difference was noted in PLP concentration between Group 1 (five post-menopausal women with a history of atherosclerosis who were undergoing maintenance hemodialysis therapy) and Group 2 (six subjects who were non-symptomatic). However, both groups had significant increases in PLP concentrations between the pre- and post-supplementation periods (p less than .01). In contrast, there was a statistically significant difference in total plasma cholesterol and very-low-density- and low-density-lipoprotein (VLDL and LDL) cholesterol concentrations between groups, but no significant changes in total cholesterol or VLDL and LDL cholesterol content were found during vitamin B-6 supplementation. No statistically significant differences in HDL, HDL2, and HDL3 cholesterol concentrations were observed between Group 1 and Group 2 subjects or within either group during vitamin B-6 supplementation.

Pharmacokinetics of amantadine hydrochloride in subjects with normal and impaired renal function.

Amantadine is useful for the prevention and treatment of influenza A and for the treatment of Parkinson's disease and drug-induced extrapyramidal disorders. We have compared the pharmacokinetics of amantadine in patients with impaired or negligible renal function to that in normal subjects. The half-life of elimination in subjects with normal renal function was 11.8 +/- 2.1 hours (range, 9.7 to 14.5 h). Eight patients with various degrees of renal insufficiency (creatinine clearance from 43.1 to 5.9 mL/min . 1.73 m2) had half-lives of elimination from 18.5 h to 33.8 days. We also studied 10 patients on thrice-weekly hemodialysis. Assuming complete bioavailability of the drug, less than 5% of the dose was removed by each 4-hour hemodialysis. The mean half-life of elimination during chronic hemodialysis was 8.3 days (range, 7.0 to 10.3). We present guidelines for use of amantadine in patients with impaired renal function, including those on maintenance hemodialysis.