Lactation and drugs

Breast-feeding is the preferred form of infant nutrition. The vast majority of medications are safe for lactating mothers and their children, and insufficient information on drugs and lactation often leads to unwarranted premature weaning due to fear of potential risk to the child. Occasionally, lack of knowledge may also lead to drug-induced reduction of milk supply. Basic pharmacological knowledge will assist paediatricians in caring for nursing dyads. Important, interrelated concepts include the milk:plasma ratio and its variation over time, the relative infant dose, and differences in milk transfer and infant clearance of drugs with gestational and chronological age. In general, the safest drugs are those that are ionised, protein bound, of high molecular weight, lipid insoluble, and of normal to lower pH. Reference works are available to assist physicians in their assessment of the risks and benefits of specific drugs in individual patients.