title: Single and multiple dose pharmacokinetics of acetaminophen (paracetamol) in polymedicated very old patients with rheumatic pain.
abstract: OBJECTIVE
  To determine whether multiple dosing of acetaminophen would result in drug accumulation in polymedicated elderly patients with rheumatic pain.
  
  
  METHODS
  Twelve inpatients (11 women), aged 89 +/- 4 years, weight 59 +/- 10 kg, receiving 3 to 8 concomitant medications, entered the study. Their creatinine clearance according to the Cockroft-Gault formula was 42 +/- 12 ml/min. The pharmacokinetics of 1 g acetaminophen was evaluated after the first dose (D1) and after the last dose (D7) during a 3 times daily regimen of 1 g for 5 consecutive days.
  
  
  RESULTS
  The plasma pharmacokinetic profile of acetaminophen did not change significantly at D7 compared to D1. No significant within-patient differences were observed, especially with respect to plasma elimination half-life (2.74 +/- 0.48 and 2.77 +/- 0.32 hours, respectively), area under the concentration-time curve (82.5 +/- 21.1 and 90.1 +/- 15.2 microg x h/ml, respectively), and apparent oral clearance (3.68 +/- 0.85 and 3.28 +/- 0.52 ml/min/kg, respectively).
  
  
  CONCLUSIONS
  No drug accumulation occurred during multiple dosing with acetaminophen in these very old subjects. On the basis of pharmacokinetic data alone, a dose regimen of acetaminophen 1 g tid seems to be appropriate in such patients.
authors.affiliation: Department of Rheumatology, Groupe Hospitalier Pellegrin, Bordeaux, France. bernard.bannwarth@thera.u-bordeaux2.fr
authors.forename: B
authors.initials: B
authors.lastname: Bannwarth
authors.forename: F
authors.initials: F
authors.lastname: Pehourcq
authors.forename: F
authors.initials: F
authors.lastname: Lagrange
authors.forename: M
authors.initials: M
authors.lastname: Matoga
authors.forename: S
authors.initials: S
authors.lastname: Maury
authors.forename: M
authors.initials: M
authors.lastname: Palisson
authors.forename: M
authors.initials: M
authors.lastname: Le Bars
mesh_terms: D000082:Acetaminophen / Q000493:pharmacokinetics* / Q000627:therapeutic use; D000368:Aged; D000369:Aged, 80 and over; D018712:Analgesics, Non-Narcotic / Q000493:pharmacokinetics* / Q000627:therapeutic use; D019540:Area Under Curve; D004359:Drug Therapy, Combination; D005260:Female; D016330:Frail Elderly; D006801:Humans; D008297:Male; D010146:Pain / Q000188:drug therapy*; D012216:Rheumatic Diseases / Q000188:drug therapy / Q000378:metabolism*
chemical_list: D018712:Analgesics, Non-Narcotic; D000082:Acetaminophen