Metoprolol (Toprol)

My wife is taking 100 mg. of Toprol XL. Our baby is due next week and her intentions are to breastfeed. Her doctor say's that this is no problem. I can't help but be concerned, given that what a mother eats or drinks is passed to the baby, and I don't believe this drug has been out long enough for a case study to determine long-term effects on the body.

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Debbi Donovan

Debbi Donovan is a Board Certified Lactation Consultant, as well as a retired La Leche League Leader. For more than a decade, Debbi... Read more

Toprol XL (metoprolol) is used to treat hypertension, angina and tachyarrhythmias. It is approved by the American Academy of Pediatrics for use in nursing moms. There are three studies that I am aware of (cited below) looking at the excretion of metoprolol into breastmilk.

I can understand your concern for your wife's health and the health of your baby. In Medications and Mothers' Milk, Dr. Tom Hale states, "Though these levels are probably too low to be clinically relevant, clinicians should use metoprolol under close supervision and with caution" (Hale, 1997). Dr. Hale, also states that the amount of metoprolol transferred to the nursing baby is quite small. This medication peaks in the bloodstream and mothers' milk approximately 2.5 to 3 hours following administration. (When dosing in a nursing mom, it is wise to avoid the peak.)

Almost all mothers and their nursing babies will be exposed to some over-the-counter or prescription medications during lactation. Most present no problem at all to the nursing baby. In fact, with most medications a baby receives no more than 0.5 to 1 percent of the maternal dose.

Benefits of a medication must always be weighed against possible/theoretical risks (to mom or baby.) It is important to keep in mind the alternative to mothers' milk -- formula. Artificial feeding will deny the baby his mother's milk, which is so important to him nutritionally and immunologically. Jack Newman, MD, founder and director of the Breastfeeding Clinic at the Hospital for Sick Children in Toronto, states that "it is rare for the risk of breastfeeding (with maternal medication) to outweigh the risk of formula." Nevertheless, it is important for nursing mothers to check with their Health Care Provider and Lactation Consultant if they will be using any medication during lactation.

References:

  • Medications and Mothers' Milk, Tom Hale, R.Ph., Ph.D., 1997
  • Kulas J, et al. Atenolol and metoprolol, a comparison of their excretion into human breast milk. Acta Obstet Scand 118(Suppl)65-9, 1984
  • Liedholm H, et.al. Accumulation of atenolol and metoprolol in human breast milk. Eur J Clin Pharmacol 20:229-31, 1981
  • Sandstrom B, Regardh CG. Metoprolol excretion into breast milk. Br J Clin Pharmacol 9:518-9,1980

I hope this information helps you and your wife in your decision. My very best wishes for a good birth and a safe birth!

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