Among 11 moLhers, only limited amounts of nicardipine were found in their milk under steady-state conditions (Jarreau 2000).
With nifedipine and its active pyridine metabolites, a maximum of 2-10|ig/kg daily is transmitted to the infant when the mother takes 30-90 mg a day. That is less than 5% of a weight-related child's dose. Average values of 2% and less are probably even more realistic (Murray 1992, Manninen 1991, Ehrenkranz 1989, Penny 1989). Nifedipin is also used successfully to treat Raynaud phenomenon of the breast nipple. Anderson (2004) reports on 12 breastfeeding women complaining of pain in the nipple, which was finally diagnosed as Raynaud phenomenon. Those choosing nifedipin therapy instantly improved. Of the 12 women, 8 had been treated with antimycotics previously because of suspected mycosis.
With 6x60 mg of nimodipine, maximum concentrations of 3.5 [ig/l were described ¡n the mother's milk (Tonks 1995). Mathematically, this would be only 0.01°/o of the weight-related maternal dosage. A further case study confirms this limited transfer of nimodipine (Carcas 1996).
With nitrendipine, a maximum relative dosage of 0.6%, including its metabolites, can reach the infant (White 1989).
Among breastfed infants, no intolerance to the calcium antago nists mentioned has been reported.
Verapamil and diltiazem are covered in section 4.6.10, on antiarrhythmics.
There is insufficient documented experience with amlodipine, felodipine, flunarizine, gaiiopamil, isradipine. lacidipine, lercani-dipine, nilvadipine, and nisoldipine.
Recommendation. Diltiazem, nifedipine, nitrendipine, and verapamil are the calcium antagonists of choice during breastfeeding. The results with nicardipine and nimodipine do not suggest any risk. Individual doses of other calcium antagonists do not require limitation of breastfeeding, but therapy should be changed.
Was this article helpful?
For many years, scientists have been playing out the ingredients that make breast milk the perfect food for babies. They've discovered to day over 200 close compounds to fight infection, help the immune system mature, aid in digestion, and support brain growth - nature made properties that science simply cannot copy. The important long term benefits of breast feeding include reduced risk of asthma, allergies, obesity, and some forms of childhood cancer. The more that scientists continue to learn, the better breast milk looks.