Bisoprolol use seems to be increasing from the queries I receive. It is difficult to assess safety as published information relies on one study where the level in milk was undetectable BUT the baby was not given any of its mother’s milk. If other beta blockers are not suitable then the baby should be monitored closely for side effects and particularly hypo-glycaemia if newborn.
The manufacturer states that small amounts (<2%) are secreted into milk of animals. If used during breastfeeding monitor the baby for drowsiness, lethargy, weight gain and effective feeding