Quinapril and its metabolite quinaprilat in human milk

• Published in: British journal of clinical pharmacology Vol. 51; no. 5; pp. 478 - 481
• Main Authors: Begg, E. J., Robson, R. A., Gardiner, S. J., Hudson, L. J., Reece, P. A., Olson, S. C., Posvar, E. L., Sedman, A. J.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Science Ltd 01.05.2001; Blackwell Science; Blackwell Science Inc
• Subjects: Adolescent; Adult; Angiotensin-Converting Enzyme Inhibitors - metabolism; Angiotensin-Converting Enzyme Inhibitors - pharmacokinetics; Antihypertensive agents; Biological and medical sciences; Breast Feeding; Cardiovascular system; Female; Humans; Isoquinolines - blood; Isoquinolines - metabolism; Isoquinolines - pharmacokinetics; Medical sciences; Middle Aged; milk; Milk, Human - chemistry; Milk, Human - metabolism; pharmacokinetics; Pharmacology. Drug treatments; Quinapril; quinaprilat; Short Reports; Tetrahydroisoquinolines; Human; Quinapril; Quinaprilat; Single dose; Oral administration; Milk transfer; Breast feeding; Blood plasma; Distribution; Antihypertensive agent; Female; Pharmacokinetics; ACE inhibitor; Breast milk
• ISSN: 0306-5251; 1365-2125
• DOI: 10.1046/j.1365-2125.2001.01327.x

Aims  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.