Transfer of Methylprednisolone into Breast Milk in a Mother with Multiple Sclerosis

High-dose intravenous methylprednisolone, a glucocorticoid with powerful anti-inflammatory activities, has become increasingly important in treating acute relapses of multiple sclerosis (MS). This is a case report of a 36-year-old lactating female who was receiving a 3-day course of high-dose methylprednisolone (1000 mg IV) to treat MS. Breast milk samples were obtained at 1, 2, 4, 8, and 12 hours following a 2-hour intravenous infusion on days 1, 2, and 3. The relative infant dose was found to be 1.45%, 1.35%, and 1.15% for days 1, 2, and 3, respectively. Using the average measured concentrations (C_avg) for days 1, 2, and 3, the estimated infant exposure was 0.207, 0.194, and 0.164 mg/kg/day, respectively, which is below the recommended dose given to neonates requiring methylprednisolone drug therapy. Infant exposure is low and mothers could continue to breastfeed if treatment with IV methylprednisolone is very brief. However, if the mother wishes to limit infant exposure further, she could wait 2 to 4 hours after IV methylprednisolone administration, thus significantly limiting the amount of drug in the breast milk.