Historically, the use of any medication by a nursing mom caused doctors to put the brakes on breastfeeding.
A review of the information provided by the medication manufacturer shows that 80% of available medications are not recommended for use during pregnancy and breastfeeding. Researchers suggest this recommendation is not based on any data collected by the drug makers, but is easier than proving it is safe for the small population of patients that are lactating.
In many cases, mothers are put in the position of weighing the risks of avoiding an important medication treatment for herself against formula feeding her infant. Research shows, most doctors take the conservative approach and discourage mothers they prescribe medication from breastfeeding. New data shows this approach harms infants by depriving them of breast milk unnecessarily, and drug levels in breast milk are miniscule, resulting in no observable long-term negative effects.
Fortunately, there is a resource for mothers and medical professionals. The best, most reliable database of medication and mother’s milk is LactMed (http://toxnet.nlm.nih.gov/newtoxnet/lactmed.htm). It is easy to use and free to access. LactMed lists 450+ medications, giving information about drug levels in milk, infant blood, possible adverse reactions and possible alternative therapies for mothers and doctors to consider.
If you need to take a medication, check out LactMed before you make any decsions about breastfeeding. In almost all cases, the levels of medication in your breast milk will not outweigh the risks of formula feeding.