Premium
Verapamil protein binding in patients and in normal subjects
Author(s) -
Keefe Deborah L,
Yee YinGail,
Kates Robert E
Publication year - 1981
Publication title -
clinical pharmacology and therapeutics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.941
H-Index - 188
eISSN - 1532-6535
pISSN - 0009-9236
DOI - 10.1038/clpt.1981.4
Subject(s) - verapamil , medicine , pharmacokinetics , dialysis , endocrinology , metabolite , plasma protein binding , pharmacology , cardiology , urology , calcium
Verapamil plasma protein binding was studied in four groups of 12 subjects each: (1) normal subjects; (2) patients with moderate renal insufficiency and patients requiring dialysis; (3) patients 1 to 4 days after coronary artery surgery; and (4) patients undergoing cardiac catheterization. In normal subjects, plasma protein binding of verapamil was 89.6 ± 0.17% and was concentration independent over a range of 35 to 1,557 ng/ml, which includes the usual clinical plasma range. In normal subjects, plasma protein binding of verapamil was not affected by addition of its major metabolite, norverapamil, in ratios of 1.2 to 26.3 (norverapamil/verapamil) or by the addition of 10 µg of warfarin. The plasma protein binding of verapamil was not altered in the postsurgical state or in the dialysis patients. Verapamil protein binding was initially lower in the cardiac catheterization patients (x̄ = 86.34 ± 2.13%, p < 0.001) than in normal subjects and was still lower (x̄ = 83.29 ± 3.04%, p < 0.02) after heparinization. There was also a small increase in binding in the patients with renal insufficiency (p < 0.05). Plasma protein binding of verapamil in mongrel dogs (x̄ = 90.7%) was of the same order. We found verapamil to be approximately 90% bound in man and dogs and not markedly changed by any of the conditions studied. Clinical Pharmacology and Therapeutics (1981) 29, 21–26; doi: 10.1038/clpt.1981.4