You may report side effects to FDA at 1-800-FDA-1088.Regular release: 50 to 100 mg orally 4 times a day for 1 week or for at least 3 days after urine sterility is obtainedRegular release: 50 to 100 mg orally once a day at bedtimeOther drugs may interact with nitrofurantoin, including prescription and over-the-counter medicines, vitamins, and herbal products. The recommended nitrofurantoin dosage for treating UTIs in adults is 50 to 100 mg four times daily, continued for at least three days after the infection has cleared. Approximately 20% to 25% of a single dose of nitrofurantoin is recovered from the urine unchanged over 24 hours. The usual dose of nitrofurantoin to prevent a urinary tract infection is 50mg to 100mg once a day at night. Antibiotics Might Lower Effectiveness of Birth Control Pill Diseases & Conditions Shake the oral liquid forcefully before each dose to make sure the medicine is evenly mixed. For treatment of urinary tract infections: Adults and teenagers—50 to 100 milligrams (mg) every six hours. Nitrofurantoin is an antibacterial agent specific for urinary tract infections. Based on urinary pharmacokinetic data, the extent and rate of urinary excretion of nitrofurantoin from the 100 mg Macrobid capsule are similar to those of the 50 mg or 100 mg Macrodantin® (nitrofurantoin macrocrystals) capsule. If you log out, you will be required to enter your username and password the next time you visit. Because of the potential for serious adverse reactions from nitrofurantoin in nursing infants under one month of age, a decision should be made whether to discontinue nursing or to discontinue the drug, taking into account the importance of the drug to the mother. It may prevent the medicine from working properly. Nitrofurantoin is bactericidal in urine at therapeutic doses. Treatment of this type of patient carries an increased risk of toxicity because of impaired excretion of the drug.Because of the possibility of hemolytic anemia due to immature erythrocyte enzyme systems (glutathione instability), the drug is contraindicated in pregnant patients at term (38 to 42 weeks gestation), during labor and delivery, or when the onset of labor is imminent. DESCRIPTION. Use only the type of antacid your doctor recommends. The broad-based nature of this mode of action may explain the lack of acquired bacterial resistance to nitrofurantoin, as the necessary multiple and simultaneous mutations of the target macromolecules would likely be lethal to the bacteria.Development of resistance to nitrofurantoin has not been a significant problem since its introduction in 1953. If you use this medicine long-term, for prevention of UTI, you may need frequent medical tests at your doctor's office. To help clear up your infection completely, keep taking this medicine for the full time of treatment, even if you begin to feel better after a few days. Some antacids can make it harder for your body to absorb nitrofurantoin.Get emergency medical help if you have any of these sudden chest pain or discomfort, wheezing, dry cough or hack;fever, chills, body aches, tiredness, unexplained weight loss;liver problems--nausea, upper stomach pain, itching, tired feeling, loss of appetite, dark urine, clay-colored stools, jaundice (yellowing of the skin or eyes); orlupus-like syndrome--joint pain or swelling with fever, swollen glands, muscle aches, chest pain, vomiting, unusual thoughts or behavior, and patchy skin color.Serious side effects may be more likely in older adults and those who are ill or debilitated.This is not a complete list of side effects and others may occur. Bulging fontanels, as a sign of benign intracranial hypertension in infants, have been reported rarely.In subacute pulmonary reactions, fever and eosinophilia occur less often than in the acute form. There is no specific antidote, but a high fluid intake should be maintained to promote urinary excretion of the drug. Skipping doses may also increase your risk of further infection that is resistant to antibiotics. The The chemical name of nitrofurantoin macrocrystals is 1-[[[5-nitro-2-furanyl]methylene]amino]-2,4-imidazolidinedione.