title: Duration of increased bleeding tendency after cessation of aspirin therapy.
abstract: BACKGROUND
  Aspirin has a significant effect on hemostasis, so it is often recommended that patients taking aspirin discontinue treatment before elective surgery. While off aspirin, these patients may be at risk of thrombosis. The optimum period of time that aspirin should be withheld is controversial. The aim of this study was to establish the duration of the antihemostatic effect of prolonged aspirin therapy.
  
  
  METHODS
  In a prospective study, 51 healthy volunteers were randomly assigned into 3 groups, each receiving an identical tablet for 14 days. One group received a placebo tablet; individuals in the other two groups received either 75 mg or 300 mg of aspirin once a day. Template bleeding times and specific platelet function testing (using the PFA-100; Dade Behring) were carried out on subjects before therapy and again after its completion until they returned to baseline.
  
  
  RESULTS
  Thirty-eight volunteers complied sufficiently with the protocol to provide useful results. All bleeding times normalized within 96 hours and all platelet function tests within 144 hours after stopping aspirin. There was no demonstrable hemostatic defect in any volunteer persisting by or beyond the sixth day after treatment cessation. There was no apparent difference in duration of effect between those taking either 75 mg or 300 mg of aspirin.
  
  
  CONCLUSIONS
  This study uses sensitive measures of platelet function to demonstrate the duration of increased bleeding tendency after withdrawal of aspirin therapy. It supports discontinuation of aspirin therapy 5 days before elective surgery (with the operation being performed on the sixth day).
authors.affiliation: Department of Surgery, NUI (Cork), Cork University Hospital, Cork, Ireland.
authors.forename: Ronan A
authors.initials: RA
authors.lastname: Cahill
authors.forename: Gerard T
authors.initials: GT
authors.lastname: McGreal
authors.forename: Basil H
authors.initials: BH
authors.lastname: Crowe
authors.forename: Damien A
authors.initials: DA
authors.lastname: Ryan
authors.forename: Brian J
authors.initials: BJ
authors.lastname: Manning
authors.forename: Mary R
authors.initials: MR
authors.lastname: Cahill
authors.forename: H Paul
authors.initials: HP
authors.lastname: Redmond
mesh_terms: D000328:Adult; D001241:Aspirin / Q000008:administration & dosage*; D001760:Bleeding Time; D004311:Double-Blind Method; D005260:Female; D006487:Hemostasis / Q000187:drug effects*; D006801:Humans; D008297:Male; D010975:Platelet Aggregation Inhibitors / Q000008:administration & dosage*; D010979:Platelet Function Tests; D011446:Prospective Studies
chemical_list: D010975:Platelet Aggregation Inhibitors; D001241:Aspirin