Is Macrobid (Nitrofurantoin) Safe To Use While Pregnant?

In our latest question and answer, the pharmacist discusses safety concerns regarding the use of Macrobid (nitrofurantoin) during pregnancy.

Dec 22, 2017

Yessy asked

I am currently 13 weeks and 3 days pregnant. And was prescribed Macrobid 100mg 2x a day for 5 days to cure a UTI. Is this medication safe ? Will it harm the baby? Really worried...

Answer

Macrobid (nitrofurantoin) is an antibiotic commonly used for the treatment of bacterial urinary tract infections and cystitis (inflammation of the bladder). Macrobid is classified as pregnancy category B.

Pregnancy Category B

"Animal reproduction studies have failed to demonstrate a risk to the fetus and there are no adequate and well-controlled studies in pregnant women."


It is important to note that there are no antibiotics classified in pregnancy category A. As such, Macrobid is generally considered safe and effective for use during pregnancy. It is recommended as a first line antibiotic option by the American Academy Of Pediatrics and the American Congress Of Obstetricians & Gynecologics.

While Macrobid is recommended as a first line therapy option for the treatment of urinary tract infections during pregnancy, it's use is contraindicated (i.e. should not be used) during pregnancy at term (38—42 weeks gestation) and during labor or obstetric delivery. This is because Macrobid can induce hemolytic anemia in certain patients. Hemolytic anemia is a condition in which the red blood cells are destroyed and eliminated from the blood prematurely. For this reason, Macrobid is also not recommended for use in neonates under one month of age.

To reiterate, Macrobid is considered safe during pregnancy, up to 32 weeks gestation. The package insert of Macrobid references animal studies in which doses up 25 times the normal human dose revealed no evidence of impaired fertility or harm to the fetus. As Macrobid is a pregnancy category B drug, there are, however, no adequate and well-controlled studies in pregnant women.

Breast-feeding

In regard to breast feeding on nitrofurantoin, the drug is distributed into breast milk and should be used with caution in breast-feeding women. It's use should be avoided in infants that have known G6PD deficiency (an enzyme necessary for normal red blood cell function), because of the risk of hemolytic anemia. This is especially true of infants under one month of age.

For infants over one month of age with no known G6PD deficiency, nitrofuratntoin is considered to be usually compatible with breast-feeding by the American Academy of Pediatrics.

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