Glyburide and Glipizide Safe for Breast-Feeding
The use of earlier-generation sulfonyl-ureas during breast-feeding was discouraged after studies with tolbutamide (e.g., Orinase®, Pharmacia/Upjohn) and chlor-propamide (Diabinese®, Pfizer) showed significant transfer of these substances into breast milk. Two small studies now suggest that the second-generation sul-fonylureas—including glyburide (DiaBeta®, Aventis) and glipizide (Glucotrol generic, Pfizer)—don’t pose the same problem.
Researchers from the University of Toronto, Mount Sinai Hospital, and The Hospital for Sick Children, all in Toronto; Miller Children’s Hospital, in Long Beach, California; and the University of California in San Francisco, gave the women a single oral dose of glyburide 5 or 10 mg. Drug concentrations were measured in maternal blood and milk for eight hours after the dose was given.
In a separate study, five women received glyburide or glipizide 5 mg/day starting on the first postpartum day. For five to 16 days after delivery, drug concentrations in the mothers’ blood and milk were measured, as were the infants’ blood glucose levels.
In the single-dose study, neither drug was detected in breast milk, even though plasma levels were invariably detected. In the daily-dose study, only one woman had a detectable serum level of glipizide.
Three wholly breast-fed infants had normal blood glucose levels (one infant’s mother received glyburide, and two infants’ mothers received generic glipizide).
Another infant in the glyburide group had normal blood glucose levels, but the mother had supplemented breast-feeding with formula. Glucose levels were not measured in the remaining infant, whose mother also used formula.
