To Terry Dise, MD:

Acebutolol and diacetolol(it major metabolite) appear in significant
concentrations with the  milk:plasma ratio varying from 1.9 to 9.2 for
acebutolol,  and 2.3 to 24.7 for diacetolol(metabolite) following a maternal
dose of  0.2 to 1.2 gm/day.    Approximately  3.5% of the Maternal dose
appears to be secreted into milk.   When the metabolite content is added,
the total drug secreted into milk approached 10 % of the maternal dose.
Hypotension, bradycardia and transient tachypnea have been reported.   Even
after discontinuing the drug,  the milk levels were consistently higher for
some time.  Although the authors cannot explain this,  I would suggest that
this product may have a high volume of distribution.  The authors suggest
that doses of 400-600 mg/day,   provide milk levels of acebutolol of about 4
mg/Liter.    Chemically,  the drug has a high pKa=9.41 which would
predispose to higher milk levels.

Acebutolol is a cardio-selective beta blocker with Intrinsic Sympathomimetic
Activity(ISA)  unlike most of the other BBs.  The only other BB that are
indicated for PVCs  is Bisprolol(Zebeta)(<2% of dose is secreted in milk)
and propranolol(Inderol).  Propranolol's milk:plasma ratio is approximately
0.5.  Daily intake would be approx 0.01 mg/day,  which is considered safe.



Boutroy, MJ  et.al.  To nurse when receiving acebutolol: Is it dangerous for
the neonate?   Eur.J. Clin.Pharmacol. (1986)  30: 737.

(Send me your FAX #  and I'll Fax it to you if you need it.)

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T.W. Hale, Ph.D.
Associate Professor of Pediatrics
Texas Tech University School of Medicine

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