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Pharmacokinetics of procainamide intravenously and orally as conventional and slow‐release tablets
Author(s) -
Graffner Christina,
Johnsson Gillis,
Sjögren John
Publication year - 1975
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/cpt1975174414
Subject(s) - procainamide , pharmacokinetics , pharmacology , chemistry , oral administration , active metabolite , metabolite , absorption (acoustics) , volume of distribution , gastrointestinal tract , first pass effect , medicine , anesthesia , biochemistry , physics , acoustics
Pharmacokinetics of procainamide were studied in healthy volunteers after single doses intravenously and orally as conventional and slow‐release tablets and after repeated oral doses to steady state. The initial distribution after intravenous administration was rapid and the overall elimination in the ß‐phase corresponded to t Û of 2.7 hr. The mean volume of the central compartment was small and only 4% of Vd(ß), which was 2.3 l/kg body weight. About 65% was excreted unchanged after intravenous administration and about 55% after a single oral dose of 500 mg. The recovery of the metabolite N‐acetylprocainamide was 12% after both routes of administration. Procainamide was completely absorbed from the gastrointestinal tract and the first‐pass elimination was very limited. The rates of absorption from the tablet compositions were weil correlated to the in vitro dissolution properties. Administration of slow‐release tablets every 8 hr gave about the same mean plasma level at steady state as ordinary tablets given every 4 hr, and the availability was the same from both preparations. The occasional high plasma concentration peaks after ordinary tablets were not observed after the slow‐release tablets. Renal clearance was about 500 ml/min, indicating an active secretion in the tubules.