A recent research report published in The Annals of Pharmacotherapy examined the reliability of 10 sources of information on the safety of drugs during lactation. The sources included databases used by two retail pharmacy chains, available text references, and electronic references.

A list of sources follows:

American Academy of Pediatrics (AAP) – published periodically and available free online

LactMed – free online resource from the National Library of Medicine

Medications and Mother’s Milk (MMM) – book updated every two years; online subscription service available

Drugs in Pregnancy and Lactation (DPL) – book updated last in 2005

Microdex – online and handheld resource

Lexi-Comp – handheld and web-based resource used by pharmacies and prescribers

Epocrates – handheld and web-based resource used by pharmacies and prescribers

First DataBank – retail pharmacy database

Clin-eguide – retail pharmacy database

Physician’s Desk Reference (PDR) – compilation of package inserts from manufacturers

The authors selected 14 drugs for review. They included drugs widely recognized as safe, drugs widely recognized as unsafe, and drugs that fit into neither category.

Sources containing the highest number of drugs rated as safe were MMM and LactMed. Microdex and DPL had numbers similar to AAP’s, but there were several discrepancies between their recommendations and AAP’s.

The two retail pharmacy databases, Lexi-Comp, and the PDR had the fewest number of safe drugs. In addition, some drugs widely accepted as safe were not listed as safe.

A summary of the authors’ conclusions follows:

“Many recommendations are not supported by up-to-date research.”

“Recommendations from the retail pharmacies mostly do not reflect AAP or any current resource.”

“Unreliable printed lactation recommendations may undermine the clinician who tells the patient, appropriately, that a drug is safe.”

“A patient who reads the warning: Do not use while breastfeeding, may be hesitant to use the drug or breastfeed, even if the prescriber reassures her that it is safe.”

What are the implications for health care providers?

Review more than one source.

Know the characteristics of the drug. Drugs with low bioavailability, large molecular weight, short half-life, short peak interval, high protein binding, and low fat solubility are least likely to transfer into human milk.

Know the characteristics of the infant – gestational age, post-birth age, weight, health. Drugs that may be safe for term, healthy infants may be unsafe for premature or sick infants.

Choose the safest drug available.

Monitor mother and baby for adverse effects.

Consider the risks of NOT breastfeeding.