title: Circadian rhythm of serum sulfate levels in man and acetaminophen pharmacokinetics.
abstract: The circadian variation of serum inorganic sulfate levels was studied in healthy volunteers. The effect of subchronic acetaminophen administration (650 mg q.i.d. for 4 days) on serum inorganic sulfate levels was investigated and the possible role of fluctuating serum inorganic sulfate levels on the pharmacokinetics of acetaminophen was evaluated. During a 24 h cycle, serum inorganic sulfate levels were lowest in the morning (11.00 h) and typically increased in the afternoon to reach a maximum in the early evening (19.00 h). Average 24 h serum concentrations were 360 microM and the difference between minimum and maximum levels was on average 25.8%. Subchronic administration of acetaminophen (650 mg q.i.d. for 4 days) significantly reduced serum inorganic sulfate levels to a 24 h average of 253 microM. The circadian rhythm, however, was not affected and the difference between minimum (12.00 h) and maximum (18.50 h) serum concentrations was 31.3%. Subchronic acetaminophen administration lead to a significant decrease in the renal excretion (-51%) and renal clearance (-33%) of inorganic sulfate. No significant differences were found in the disposition kinetics of acetaminophen and its glucuronide and sulfate conjugates during two consecutive dosing intervals (08.00-14.00 h, 14.00-20.00 h) on Day 4 of the acetaminophen regimen.
authors: College of Pharmacy, University of Saskatchewan, Saskatoon, Canada.
authors: D A
authors: DA
authors: Hoffman
authors: S M
authors: SM
authors: Wallace
authors: R K
authors: RK
authors: Verbeeck
mesh_terms: D000082:Acetaminophen / Q000493:pharmacokinetics*; D000328:Adult; D002940:Circadian Rhythm; D005965:Glucuronates / Q000097:blood; D006801:Humans; D008297:Male; D013431:Sulfates / Q000097:blood*
chemical_list: D005965:Glucuronates; D013431:Sulfates; D000082:Acetaminophen