title: Risk factors for adverse events in analgesic drug users: results from the PAIN study.
abstract: BACKGROUND
  The relative influence of various risk factors for adverse events (AE) in analgesics users have never been precisely quantified. Advantage was taken of data generated in the paracetamol, aspirin and ibuprofen new tolerability (PAIN) study, a large randomized double-blinded trial of paracetamol, aspirin or ibuprofen for common pain in general practice to attempt this.
  
  
  OBJECTIVE
  Identify and quantify factors associated with the occurrence of AE in users of analgesic drugs.
  
  
  METHODS
  Multivariate logistic regression analysis of potential risk factors for all AE, clinically significant AE (SAE) and clinically significant gastro-intestinal AE (GI SAE).
  
  
  RESULTS
  Of the 8677 patients included in the study, 8633 contributed data. The main risk factors for SAE were indication: compared to those treated for musculoskeletal pain, patients treated for menstrual pain had an odds ratio (95% Confidence Interval) of 0.4 (0.2-0.7), sore throat 0.6 (0.5-0.8), cold and flu 0.7 (0.6-0.8), headache 0.8 (0.7-1.0); concomitant use of medication contra-indicated in the drugs' labeling (OR: 2.2; 1.6-2.9); increasing number of other concomitant medications: 1: OR 1.5 (1.3-1.8); 2-3: OR 1.9 (1.6-2.3); more than 3: OR (2.7; 2.1-3.5); treatment with aspirin: OR 1.4; (1.2-1.6) but not ibuprofen: OR 0.9; (0.8-1.1) compared to paracetamol; history of previous GI disorder OR 1.4 (1.0-1.8); female gender: OR 1.3 (1.1-1.4). Age was not significantly associated with AE in the multivariate analysis. Risk factors for all AE and GI SAE were mostly the same as for significant AE, but there were fewer GI SAE with ibuprofen than with paracetamol (OR 0.8; 0.6-0.9).
  
  
  CONCLUSIONS
  Apart from the analgesic used and its indication, the main risk factors identified for AE in users of first-line analgesics for common pain were the number and nature of concomitant medication.
authors.affiliation: Department of Pharmacology, Université Victor Segalen, 33076 Bordeaux, France. nicholas.moore@pharmaco.u-bordeaux2.fr
authors.forename: Nicholas
authors.initials: N
authors.lastname: Moore
authors.forename: Andrew
authors.initials: A
authors.lastname: Charlesworth
authors.forename: Eric
authors.initials: E
authors.lastname: Van Ganse
authors.forename: Jean-Marie
authors.initials: JM
authors.lastname: LeParc
authors.forename: Judith K
authors.initials: JK
authors.lastname: Jones
authors.forename: Richard
authors.initials: R
authors.lastname: Wall
authors.forename: Hélène
authors.initials: H
authors.lastname: Schneid
authors.forename: François
authors.initials: F
authors.lastname: Verrière
mesh_terms: D000082:Acetaminophen / Q000008:administration & dosage; D000328:Adult; D000368:Aged; D018712:Analgesics, Non-Narcotic / Q000008:administration & dosage / Q000009:adverse effects*; D001241:Aspirin / Q000008:administration & dosage; D004311:Double-Blind Method; D005260:Female; D005602:France; D005767:Gastrointestinal Diseases / Q000139:chemically induced; D006801:Humans; D007052:Ibuprofen / Q000008:administration & dosage; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D010146:Pain / Q000517:prevention & control*; D012307:Risk Factors
chemical_list: D018712:Analgesics, Non-Narcotic; D000082:Acetaminophen; D001241:Aspirin; D007052:Ibuprofen