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Comparative effects of verapamil and isradipine on steady‐state digoxin kinetics
Author(s) -
Rodin Steven M,
Johnson Brian F,
Wilson John,
Ritchie Paula,
Johnson Johanna
Publication year - 1988
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.1988.93
Subject(s) - isradipine , digoxin , verapamil , pharmacokinetics , dihydropyridine , pharmacology , medicine , calcium channel , steady state (chemistry) , calcium channel blocker , chemistry , endocrinology , calcium , heart failure
The effects on the steady‐state digoxin pharmacokinetics of verapamil (240 mg/day) and a new dihydropyridine calcium channel blocker, isradipine (15 mg/day), were compared. Nineteen healthy white men, aged 23 to 40 years, ingested 0.25 mg digoxin tablets every 12 hours for two consecutive periods of 2 weeks. Each subject also received one of the calcium channel blockers during one of these periods, with agent and sequence randomized. Analyst‐blind RIA serum digoxin determinations demonstrated that the nine subjects who received isradipine, 5 mg t.i.d., had a small increment in peak digoxin level from 2.3 ± 0.6 to 2.9 ± 0.7 ng/ml ( p < 0.05) but no significant change in steady‐state level or AUC over 12 hours. By contrast, the 10 subjects who received verapamil, 80 mg t.i.d., showed significant increases in steady‐state (0.9 ± 0.1 to 1.3 ± 0.2 ng/ml; p < 0.001) and peak serum digoxin concentrations (2.5 ± 0.7 to 3.6 ± 0.8ng/ml; p < 0.001) and in AUC (15.7 ± 1.7 to 23.6 ± 2.9 ng · hr/ml; p < 0.001). Neither calcium channel blocker reduced renal digoxin clearance. Verapamil increases digoxin levels without affecting renal clearance. Isradipine has no clinically important interaction with digoxin. Clinical Pharmacology and Therapeutics (1988) 43 , 668–672; doi: 10.1038/clpt.1988.93