I always worry about HIGH doses of any drug.  We frequently receive calls from mothers undergoing 1000 mg IV doses of methylprednisolone for MS. I never knew for sure what to tell these moms.  Thankfully,  one lady carefully collected milk samples for three days while undergoing this IV therapy with 1000 mg of methylprednisolone and we now have the answer.   The levels in milk are really quite low,  particularly after a few hours.  This gave us really good information as to how to advise moms undergoing this therapy.  Thanks to this mom for helping hundereds of other moms.   TWH. 

Title: Transfer of methylprednisolone into breast milk in a mother with multiple sclerosis.

Authors: Cooper SD, Felkins K, Baker TE, Hale TW.

J Hum Lact. 2015 May;31(2):237-9.

Abstract:

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.

Figure: Methylprednisolone Levels in Human Milk.

Concentrations of methylprednisolone in human milk at day 1, day 2, and day 3 after intravenous doses of methylprednisolone (1000 mg).

PMID 25691380