Fluconazole stays in the system for 72 hours after taking a single 150 mg tablet, as stated by Advanced Patient Education. The drug interacts with other medications so consulting a doctor before using is important.
Fluconazole can be taken through the mouth or applied in the vagina. Women with complicated conditions need to use the drug for 7 to 14 days instead of a 3-day treatment. Breastfeeding women can still feed their babies because Fluconazole does not pass through milk. Even if it passes, the amount is so little that it cannot cause any harm to the baby. The drug should be used as directed by a doctor.