title: Quinapril and its metabolite quinaprilat in human milk.
abstract: OBJECTIVE
  To measure the milk to plasma ratio (M/P) of quinapril and its active metabolite quinaprilat in lactating mothers and to assess likely infant exposure.
  
  
  METHODS
  A single dose of quinapril 20 mg was administered to six healthy mothers who had been breastfeeding their infants for at least 2 weeks. Blood was sampled for the measurement of quinapril and quinaprilat at 0, 0.5, 1, 1.5, 2, 3, 4, 6, 8, 12, 16 and 24 h. Milk was collected for measurement of quinapril and quinaprilat concentrations over the periods -4-0, 0-4, 4-8, 8-12, 12-18, 18-24 h. The areas under the plasma and milk concentration-time curves were estimated and an M/P ratio derived for both quinapril and quinaprilat.
  
  
  RESULTS
  The M/P ratio for quinapril was 0.12 (95% CI 0.09,0.14). No quinapril was detected in milk after 4 h. No quinaprilat was detected in any of the milk samples. The estimated 'dose' of quinapril that would be received by the infant was 1.6% (95% CI 1.0,2.2) of the maternal dose, adjusted for respective weights.
  
  
  CONCLUSIONS
  Quinapril appears to be 'safe' during breastfeeding according to conventional criteria, although as always, the risk:benefit ratio should be considered when it is to be given to a nursing mother.
authors: Department of Clinical Pharmacology, Christchurch School of Medicine, New Zealand. evan.begg@chmeds.ac.nz
authors: E J
authors: EJ
authors: Begg
authors: R A
authors: RA
authors: Robson
authors: S J
authors: SJ
authors: Gardiner
authors: L J
authors: LJ
authors: Hudson
authors: P A
authors: PA
authors: Reece
authors: S C
authors: SC
authors: Olson
authors: E L
authors: EL
authors: Posvar
authors: A J
authors: AJ
authors: Sedman
mesh_terms: D000293:Adolescent; D000328:Adult; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000378:metabolism / Q000493:pharmacokinetics; D001942:Breast Feeding; D005260:Female; D006801:Humans; D007546:Isoquinolines / Q000097:blood / Q000378:metabolism / Q000493:pharmacokinetics*; D008875:Middle Aged; D008895:Milk, Human / Q000737:chemistry / Q000378:metabolism*; D000077583:Quinapril; D044005:Tetrahydroisoquinolines
chemical_list: D000806:Angiotensin-Converting Enzyme Inhibitors; D007546:Isoquinolines; D044005:Tetrahydroisoquinolines; C054501:quinaprilat; D000077583:Quinapril