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The effect of concurrent aspirin upon plasma concentrations of tenoxicam.
Author(s) -
Day RO,
Paull PD,
Lam S,
Swanson BR,
Williams KM,
Wade DN
Publication year - 1988
Publication title -
british journal of clinical pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.216
H-Index - 146
eISSN - 1365-2125
pISSN - 0306-5251
DOI - 10.1111/j.1365-2125.1988.tb03405.x
Subject(s) - tenoxicam , aspirin , volunteer , chemistry , pharmacokinetics , pharmacology , volume of distribution , medicine , endocrinology , anesthesia , piroxicam , agronomy , alternative medicine , pathology , biology
1. The effect of chronic, high‐dose aspirin therapy upon the disposition of a single dose and multiple doses of tenoxicam was examined in normal volunteers. 2. Aspirin caused a 24% drop in the t1/2 (P less than 0.005), a 49% rise in the volume of distribution (P less than 0.0003) and a 98% increase in the clearance (P less than 0.0001) of tenoxicam after a single dose of the tenoxicam. 3. Steady‐state concentrations of tenoxicam decreased significantly from 10.4 +/‐ 1.5 to 4.5 +/‐ 1.6 micrograms ml‐1 in the presence of chronic, high‐dose aspirin treatment. 4. Tenoxicam percentage free measured in plasma from a normal volunteer was 0.56 +/‐ 0.05% over the tenoxicam concentration range 1‐20 micrograms ml‐1 and rose to 1.24 +/‐ 0.07% in the presence of aspirin 150 micrograms ml‐1. 5. The effect of aspirin upon the disposition of tenoxicam was consistent with a competitive protein binding interaction.