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Hemodialysis for severe procainamide toxicity: Clinical and pharmacokinetic observations
Author(s) -
Atkinson Arthur J.,
Krumlovsky Frank A.,
Huang Chia M.,
del Greco Francesco
Publication year - 1976
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 - 10.1002/cpt1976205585
Subject(s) - procainamide , napa , pharmacokinetics , volume of distribution , toxicity , medicine , pharmacology , hemodialysis , chemistry , biochemistry
A 67‐yr‐old woman who ingested approximately 7 gm procainamide developed severe hypotension, renal insufficiency, and life‐threatening cardiac toxicity, Hemodialysis doubled the rate of procainamide elimination and increased fourfold the clearance of NA PA , the N‐acetylated metabolite of procainamide. Observations of procainamide and N‐acetylprocainamide (NAPA) plasma levels during the patient's recovery suggest that lethargy and profound hypotension can be expected when these levels total 60 µg/ml and that severe cardiac toxicity should be anticipated with levels totaling 42 µg/ml or more. Hemodialysis also permitted investigation of the effects of hypotension on the pharmacokinetics of these compounds. The apparent volume of procainamide distribution was reduced from a normal value of 2 L/kg to 0.76 L/kg, and that of NAPA from 1.4 L/kg to 0.63 L/kg. The elimination t ½ of procainamide was prolongedfrom the normal of 3 hr to 10.5 hr, and that of NAPA from 6 to 35.9 hr. Procainamide absorption was also slowed in this clinical setting, causing procainamide plasma levels to continue rising for some time after toxicity was first recognized.