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Direct determination of hepatic extraction of verapamil in cardiac patients
Author(s) -
Woodcock Barry G,
Schulz Wolfgang,
Kober Gisbert,
Rietbrock Norbert
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.1981.126
Subject(s) - verapamil , indocyanine green , medicine , vein , blood flow , anesthesia , surgery , calcium
Hepatic extraction of verapamil was determined directly in cardiac patients undergoing diagnostic catheterization and receiving 10 mg verapamil intravenously or intra‐arterially. The extraction curves of verapamil concentrations in blood from the ascending aorta and hepatic vein were similar to those reported after single intravenous doses of indocyanine green. The rectilinear fall in concentration lasted 10 to 15 min. Mean hepatic extraction of verapamil in four patients who received intravenous doses was 0.86 (range 0.84 to 0.89) and in four who received intra‐arterial doses was 0.87 (range 0.83 to 0.89). These estimates are the same as those for hepatic first‐pass extraction determined by indirect methods based on areas under plasma concentration‐time curves and requiring calculation of apparent hepatic blood flow. The results are considered to be proof that the first‐pass effect of verapamil after oral doses is attributable mainly, if not entirely, to hepatic elimination. Clinical Pharmacology and Therapeutics (1981) 30, 52–56; doi: 10.1038/clpt.1981.126