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Pyridostigmine kinetics in healthy subjects and patients with myasthenia gravis
Author(s) -
BreyerPfaff Ursula,
Maier Ulrich,
Brinkmann Anneliese M,
Schumm Fritz
Publication year - 1985
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.1985.78
Subject(s) - pyridostigmine , pyridostigmine bromide , myasthenia gravis , oral administration , chemistry , dosing , absorption (acoustics) , pharmacokinetics , plasma levels , medicine , anesthesia , pharmacology , physics , acoustics
Comparative pyridostigmine kinetics in plasma were measured in 10 healthy subjects given 4 mg iv and 60 mg oral pyridostigmine bromide. As determined from the AUC ratio, oral availability was 11.5% to 18.9% (X̄ = 14.3%). Mean t½ of the plasma level decline after oral dosing was 200 minutes, twice as long as the terminal elimination t½ after intravenous infusion (97 minutes). Thus absorption may proceed at a slower rate than elimination. Comparison of intraindividual data revealed strict dependence of the AUC on the infused dose (2, 4, and 8 mg) in one subject and variability in AUC up to a factor of two when two subjects took oral pyridostigmine three times. Patients with myasthenia who were receiving continuous therapy with oral pyridostigmine had AUC values per unit dose corresponding to those in healthy subjects. Storage stability of pyridostigmine in plasma required acidification of samples and storage at −75° C. When native plasma was kept at −20° C, there was appreciable loss of pyridostigmine within 1 to 2 months, the extent of which depended on the initial concentration. Clinical Pharmacology and Therapeutics (1985) 37, 495–501; doi: 10.1038/clpt.1985.78