To nurse when receiving acebutolol: Is it dangerous for the neonate?

Abstract

The concentrations of acebutolol and of its main active metabolite diacetolol in milk and plasma were studied in 7 hypertensive mothers treated with acebutolol, a cardioselective beta-adrenoceptor blocking agent. Clinical monitoring on their newborn babies was also done, as well as measurement of plasma level of the drug in them. The ratio between milk and plasma concentrations ranged from 1.9 to 9.2 for acebutolol and from 2.3 to 24.7 for diacetolol, and in any given milk sample, the diacetolol concentration was always higher than that of acebutolol. In a newborn infant, plasma concentrations of the two transplacentally acquired substances was raised when breast feeding started and remained high. Clinical signs of pharmacological beta-blockade were observed. Evaluation of the iatrogenic risk shows that pharmacologically active amounts of acebutolol might be received by a neonate if the daily maternal dosage exceeds 400 mg/day and/or renal function in the mother is impaired.

Excretion of Antihypertensive Medication Into Human Breast Milk: A Systematic Review

“…However, there are only two reports of an antihypertensive agent having clinical effects on a breastfed infant. One was a study on atenolol (48) and the other, acebutolol (14). In both cases, the infant became bradycardiac and tachypneic, consistent with a clinical picture of beta blockade.…”

“…Metoprolol, nadolol, acebutolol, sotalol, and atenolol have the highest M/P ratios of the beta-blockers, each averaging > 1, with reports of M/P ratios as high as 9.2 for acebutolol (14). This indicates that these drugs are freely excreted into breast milk and therefore will be ingested by the breastfed infant.…”

Maternal Medication, Drug Use, and Breastfeeding

“…48 Although rarely, atenolol and acebutolol have both been associated with infant adverse effects such as cyanosis, tachypnea, bradycardia, hypotension, and low body temperature, and are not preferred agents. 49,50 At present there is no information about the transfer of carvedilol or bisoprolol into breast milk. In summary, monitoring the infant for hypotension, bradycardia, and lethargy is suggested when using b-blockers in lactation.…”

Placental transfer and perinatal pharmacokinetics of betaxolol

“…Comparison with data for other [3-blockers indicates a higher milk/blood ratios (2.5-10) for acebutolol and a similar value (1.6-4.5) for atenolol, metoprolol, oxprenoloi and propranolol (Boutroy et al 1986;Kulas et al 1984;Liedholm et al 1981;Lundborg et al 1981;SandstrOm and Regardh 1980;Sioufi et al 1984;Thorley et al 1983;White et al 1984).…”