What are the contraindications of Macrobid (Nitrofurantoin) in the postpartum period?

Contraindications of Macrobid (Nitrofurantoin) in the Postpartum Period

Nitrofurantoin (Macrobid) is generally safe during the postpartum period for most breastfeeding mothers, with the primary contraindication being infants less than one month old due to potential risk of hemolytic anemia. 1, 2

Primary Contraindications

• Nitrofurantoin is contraindicated in mothers breastfeeding infants less than one month of age due to the risk of hemolytic anemia in newborns who have glutathione instability 2
• Mothers breastfeeding infants with known glucose-6-phosphate dehydrogenase (G6PD) deficiency should avoid nitrofurantoin due to increased risk of hemolytic reactions 1, 3
• Mothers with renal insufficiency (creatinine clearance under 60 mL per minute or clinically significant elevated serum creatinine) should not take nitrofurantoin due to increased risk of peripheral neuropathy 1

Maternal Contraindications

• History of pulmonary reactions to nitrofurantoin (acute, subacute, or chronic) 1
• History of hepatic reactions including hepatitis, cholestatic jaundice, chronic active hepatitis, or hepatic necrosis 1
• Known hypersensitivity to nitrofurantoin or any components of the formulation 1
• Anemia, diabetes mellitus, electrolyte imbalance, or vitamin B deficiency (these conditions enhance the occurrence of peripheral neuropathy) 1

Special Considerations for Breastfeeding

• While small amounts of nitrofurantoin transfer into breast milk, it is generally considered safe for breastfeeding mothers with infants older than one month 2
• If nitrofurantoin must be used in mothers breastfeeding infants under one month, the infant should be closely monitored by a physician for signs of hemolysis 2
• The risk of clinically important hemolytic reactions appears to be very rare (estimated at 1 in 100,000 courses of therapy) 4

Alternative Options

• For mothers breastfeeding infants less than one month old who require antibiotic treatment for urinary tract infections, alternative antibiotics should be considered 2
• First-line alternatives might include beta-lactams or other antibiotics with established safety profiles in breastfeeding 2

Monitoring Recommendations

• If nitrofurantoin is used in a breastfeeding mother (with infant older than one month), monitor the infant for:
  • Jaundice or pallor (signs of hemolysis) 1, 2
  • Changes in feeding patterns 1
  • Gastrointestinal disturbances 1
• Monitor the mother for early signs of adverse reactions including:
  • Respiratory symptoms (cough, dyspnea, chest pain) which could indicate pulmonary toxicity 1, 5
  • Peripheral neuropathy symptoms (numbness, tingling) 1
  • Hepatic symptoms (jaundice, right upper quadrant pain) 1

The risk-benefit assessment should favor alternative antibiotics when treating mothers who are breastfeeding infants less than one month old, as the potential risk of hemolytic anemia in the newborn outweighs the benefits of nitrofurantoin in this specific population 2, 4.