Drug levels in milk have been very low for all of the calcium-channel blocking drugs tested. In the few cases in which breastfed infants have had serum level measurements the drugs were undetectable. Studied drugs include amlodipine, diltiazem, nicardipine, nifedipine, nimodipine, and verapamil. Other calcium channel blockers have not been studied during lactation. The most extensive safety information is on nifedipine, with no reports of adverse reactions among numerous infants exposed through breast milk, including many infants whose mothers were being treated for Raynaud phenomenon of the nipple. For information on specific drugs, refer to LactMed: https://www.ncbi.nlm.nih.gov/books/NBK501922/
- Anderson PO. Drug treatment of Raynaud’s phenomenon of the nipple. Breastfeed Med 2020;15:686-8.