title: When breastfeeding mothers need CNS-acting drugs.
abstract: BACKGROUND
  Breastfeeding is the ideal method of infant nutrition. However, if mothers need medications such as the central nervous system (CNS) acting drugs, infant safety concerns arise. Summarized information on infant exposure levels to drugs in milk and associated side effect profiles will help clinicians to rationalize and justify important drug therapy for a breastfeeding patient.
  
  
  METHODS
  Electronic searches of MEDLINE and PsycINFO from 1966-2003, and of EMBASE from 1980-2003, were conducted for studies on breastfeeding or breast milk and medications in the following categories: antidepressants, antipsychotics, antiepileptics (or anticonvulsants) and anxiolytics. The infant exposure level (%) was defined as follows: [Drug concentration in milk (mg/mL)] x [Daily milk intake (mL/kg/d)] x 100 / Maternal dose (mg/kg/d).
  
  
  RESULTS
  A total of 129 papers were eligible for analyses. Our findings indicate that the majority of the CNS-acting drugs, if taken by nursing women, result in average exposure levels to their breast-fed infants of less than 10% of the therapeutic doses per kg body weight. Exceptions are lithium, ethosuximide, phenobarbital, primidone, lamotrigine and topiramate. Adverse effect profiles do not always correlate with a higher exposure level. Overall, most reported adverse effect profiles appear benign. Where adverse effects were reported, they were often confounded by intrauterine exposure.
  
  
  CONCLUSIONS
  CNS-acting drugs taken by the mother do not appear to pose any major risks of immediate adverse effects to the breastfeeding infant, although with most of the newer drugs further research is needed to be conclusive.
authors.affiliation: Department of Pediatrics, The Hospial for Sick Children, University of Toronto.
authors.forename: Evelyn T
authors.initials: ET
authors.lastname: Rubin
authors.forename: Amy
authors.initials: A
authors.lastname: Lee
authors.forename: Shinya
authors.initials: S
authors.lastname: Ito
mesh_terms: D000927:Anticonvulsants / Q000008:administration & dosage / Q000009:adverse effects / Q000493:pharmacokinetics; D000928:Antidepressive Agents / Q000008:administration & dosage / Q000009:adverse effects / Q000493:pharmacokinetics; D014150:Antipsychotic Agents / Q000008:administration & dosage / Q000009:adverse effects / Q000493:pharmacokinetics; D001942:Breast Feeding; D002491:Central Nervous System Agents / Q000008:administration & dosage / Q000009:adverse effects* / Q000493:pharmacokinetics*; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008895:Milk, Human / Q000378:metabolism*
chemical_list: D000927:Anticonvulsants; D000928:Antidepressive Agents; D014150:Antipsychotic Agents; D002491:Central Nervous System Agents