Is Verapamil safe while breastfeeding?
Here is what NIH LactMed, the U.S. National Library of Medicine's authority on medicines and breastfeeding, reports about Verapamil. This is a summary of that source — not our own verdict.
Effects on the breastfed infant
No adverse reactions have been reported among 3 infants aged 13 days, 8 weeks and 3 months who were exposed to verapamil in breastmilk.[ 2 4 ]
Effects on milk supply
Verapamil can cause hyperprolactinemia and galactorrhea.[ 6 , 7 ] The clinical relevance of these findings in nursing mothers is not known. The maternal prolactin level in a mother with established lactation may not affect her ability to breastfeed.
Levels in milk
Maternal Levels . The first 2 cases of verapamil excretion in milk found disparate results.[ 1 , 2 ] In one, milk levels ranging from 19 to 38 mcg/L were found at various times during a dosing regimen of 80 mg orally 3 times daily in a mother who was 3 to 5 days postpartum. Milk levels averaged 23% of serum levels.[ 2 ] In the second woman who was 13 days postpartum, milk levels peaked at about 300 mcg/L about 1 hour after each 80 mg dose in a 80 mg 4 times daily regimen and were approximately equal to serum levels at most times.[ 1 ] In 2 later cases (below), plasma and milk verapamil and norverapamil levels were measured using more accurate methods. The results reported in these 2 papers were consistent with each other and differed from both of the earlier studies in some aspects.[ 3 , 4 ] A woman who was 8 weeks postpartum and taking 120 mg of verapamil orally every 8 hours had milk verapamil levels of 113 and 154 mcg/L of verapamil just before a dose, with the higher level occurring later in the feeding, probably because of the higher fat content. At 4 hours after a dose, levels were 133 and 205 mcg/L early and late in the feeding, respectively. Norverapamil levels were similar early and late in each feeding and averaged 50 mcg/L before the dose and 58 mcg/L at 4 hours. The authors estimated that a nursing infant would receive less than 0.5% of the mother s weight-adjusted dosage.[ 3 ] A 3-month-postpartum woman taking verapamil 80 mg orally three times daily had peak milk levels of verapamil of 79 mcg/L 1 hour after the dose and norverapamil of 22 mcg/L 2 hours after the dose. The authors estimated that a nursing infant would receive less than 0.01% of the mother s weight-adjusted dose daily.[ 4 ] A study of a new analytic technique found verapamil concentration in the breastmilk of one nursing mother taking verapamil 80 mg daily to range from 1.8 to 10.73 mcg/L, and norverapamil to range from 2.15 to 5.15 mcg/L. The peak concentrations of the two drugs occurre
Alternatives LactMed lists
Source: NIH LactMed (National Library of Medicine).
Educational summary of an authoritative source — not medical advice. Never start, stop, or change a medicine while breastfeeding without confirming with your doctor.