Metronidazole and breastfeeding a 3 week old baby

[klowvah]

I have a 3 week old baby (almost 4 weeks). I was prescribed Metronidazole 500mg TID for 10 days for C. Difficile infection. I spoke with a midwife and a pharmacist who encouraged me to continue breastfeeding, but my family doctor is not in agreement.

I started the drug Sunday (5 days ago) and have continued to breastfeed. Am I doing the right thing?

[admin-james]

We classify Metronidazole as an L2 (out of 5) meaning that it is fairly safe with good data to support that statement. When you take Metronidazole orally and breastfeed normally, the infant gets around 13% of what you take. That would expose the infant to about 2.9 mg/kg/day (Metronidazole per baby's body weight per day). This drug is commonly given directly to infants to treat their own infections at 15-35 mg/kg/day with no adverse effects. For more information, contact the InfantRisk Center at (806)352-2519.

-James Abbey, MD

[admin-james]

The following citations may be useful to your physician:

Erickson SH, Oppenheim GL, Smith GH. Metronidazole in breast milk. Obstet Gynecol 1981; 57(1):48-50.

Passmore CM, McElnay JC, Rainey EA, D'Arcy PF. Metronidazole excretion in human milk and its effect on the suckling neonate. Br J Clin Pharmacol 1988; 26(1):45-51.

Heisterberg L, Branebjerg PE. Blood and milk concentrations of metronidazole in mothers and infants. J Perinat Med 1983; 11(2):114-120.

Bennett PN. Use of the monographs on drugs: In: Drugs and Human Lactation. Amsterdam, Elsevier, 1996.