(Though in the case of nitrofurantoin, this does not include patients with G6PD deficiency.) Some antibiotics taken by breastfeeding mothers may occasionally be. Drugs containing Nitrofurantoin: Macrobid, Macrodantin, Furadantin, Nitro Macro. Nitrofurantoin Levels and Effects while Breastfeeding. Rapid-release capsules of nitrofurantoin macrocrystals reach their peak milk levels either 1 to 2 hours after the dose with food or 4 hours after. Which medicines are safe to take while breastfeeding? Urinary-tract infection: Antibiotics in the nitrofurantoin family (Macrobid), ciprofloxacin (Cipro), and.