title: Pragmatic comparison of beta2-agonist side effects within the Worldwide Atosiban versus Beta Agonists study.
abstract: OBJECTIVE
  While beta2-agonists for the acute treatment of preterm labour unequivocally reduce the odds of delivery within 48 h and 7 days, they have been associated with substantial maternal and fetal side effects. We aimed to compare side effect profiles of beta2-agonist tocolytics.
  
  
  METHODS
  Pragmatic comparison of ritodrine, salbutamol and terbutaline from re-analysis of data obtained within three comparator arms of three simultaneous comparable randomised controlled trials of beta2-agonists against atosiban in 742 women in preterm labour. The prevalence of categoric side effects between treatment groups was analysed using a chi2 test. The differences in continuous variables between treatment groups were analysed in analyses of covariance.
  
  
  RESULTS
  The prevalence of categoric side effects was similar with the three drugs, with the exception of the subjective symptom of palpitations (ritodrine 24.0%, terbutaline 9.3% and salbutamol 12.3%, P=0.003). There were also some differences in maternal diastolic blood pressure (P<0.001) and serum glucose levels (P<0.001), although these were small (<3 mmHg and < or =2.8 mmol/L, respectively) and clinically unimportant.
  
  
  CONCLUSIONS
  Side effects were common with all three drugs. Thus, choosing one beta2-agonist over the other to minimise side effects has little rationale, especially now that safer tocolytics are available.
authors.affiliation: Institute of Reproductive and Developmental Biology, Imperial College London and Centre for Fetal Care, Queen Charlotte's and Chelsea Hospital, London, United Kingdom. j.chan@imperial.ac.uk
authors.forename: Jerry
authors.initials: J
authors.lastname: Chan
authors.forename: Dominique
authors.initials: D
authors.lastname: Cabrol
authors.forename: Ingemar
authors.initials: I
authors.lastname: Ingemarsson
authors.forename: Karel
authors.initials: K
authors.lastname: Marsal
authors.forename: Jean-Marie
authors.initials: JM
authors.lastname: Moutquin
authors.forename: Nicholas M
authors.initials: NM
authors.lastname: Fisk
mesh_terms: D000318:Adrenergic beta-Agonists / Q000009:adverse effects*; D000328:Adult; D003657:Decision Making; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D007752:Obstetric Labor, Premature / Q000188:drug therapy*; D011247:Pregnancy; D015995:Prevalence; D015149:Tocolytic Agents / Q000009:adverse effects*; D014668:Vasotocin / Q000009:adverse effects / Q000031:analogs & derivatives*
chemical_list: D000318:Adrenergic beta-Agonists; D015149:Tocolytic Agents; C047046:atosiban; D014668:Vasotocin