Generic name: Nitrofurantoin.

Other brand names: Furadantin, Furalan, Furan, Furanite, Macrobid, Nitrofan.

Macrodantin is a urinary antibiotic. It inhibits the growth of bacteria by chemically interfering with their ability to survive. 

Quick Facts About Macrodantin


Used to treat urinary tract infections caused by bacteria.

Macrodantin Dosage

Take With food to stimulate absorption. Entire prescription should be finished, even if symptoms subside. Works best if your urine is acidic; talk with your doctor about how to ensure this. Urine may turn brown.

  • Usual adult dose: Macrodantin — 50 to 100 milligrams taken 4 times per day. Long-term use dosage may be reduced to 50 to 100 milligrams taken once at bedtime. Treatment duration is for 3 days to 1 week after an infection-free urine specimen is obtained. Macrobid — one 100 milligram capsule taken every 12 hours for 7 days.
  • Usual child dose: Macrodantin — For children over one month to 12 years — 5 to 7 milligrams per 2.2 pounds of body weight divided into 4 doses in 24 hours. Long-term use — 1 milligram per 2.2 pounds of body weight taken in 1 or 2 doses per day. Macrobid — For children over 12 years — one 100 milligram capsule taken every 12 hours for 7 days. Not prescribed for children under 12 years.
  • Missed dose: take as soon as possible. Take remaining doses for the day at equal intervals.

Macrodantin Side Effects

Overdose symptoms:

vomiting. If vomiting does not happen after an excessive dose, induce vomiting. If you suspect an overdose, immediately seek medical attention.

More common side effects: lack or loss of appetite, nausea, vomiting.

Less common or rare Macrodantin side effects: abdominal pain or discomfort, chills, confusion, cough, chest pain, depression, diarrhea, difficulty breathing, dizziness, drowsiness, exaggerated sense of well-being, fever, hair loss, headache, hepatitis, hives, inflammation of nerves causing numbness, involuntary eye movement, itching, itchy red skin patches, joint pain, muscle pain, peeling skin, psychotic reactions, rash, severe allergic reactions, skin inflammation with flaking, skin swelling or welts, tingling pain or muscle weakness, vertigo, yellowing of skin and eyes, weakness.


Inform your doctor before combining Macrodantin with:

antispasmodics such as Bentyl and Donnatal, magnesium trisilicate (Gaviscon), uricosuric medications such as Benemid.

No known food/other substance interactions. 

Special Cautions

If pregnant or planning to become pregnant, inform your doctor immediately. Should not take at term of pregnancy or during labor and delivery. Not known if Macrodantin and Macrobid appear in breast milk.

No special precautions apply to seniors.

Follow doctor’s instructions carefully for children.

  • Death has occurred from peripheral neuropathy (disease of the nerves) during
  • Macrodantin therapy. Use very cautiously if you have kidney disorder, anemia, diabetes, a debilitating disease, or vitamin B deficiency — these conditions increase the risk of peripheral neuropathy.
  • Doctor should closely monitor changes in liver function for signs of hepatitis. Hepatitis has caused death during long-term treatment with this medication.
  • Do not take if you have a kidney disorder, are unable to produce urine, or produce only a small amount
  • Monitor for breathing disorders. Pulmonary fibrosis (abnormal increase in fibrous tissue in the lungs) develops gradually and can be fatal.
  • Allergic reactions may occur with no warning. Reactions are rare and happen with long-term therapy (6 months or more). Lung reactions often occur in the first week of therapy and disappear when therapy is stopped.
  • May be at risk for below normal hemoglobin content in the blood as a result of red blood cell destruction.
  • If sensitive to or allergic to this or similar medications, should not take.
  • Notify your doctor of any unusual symptoms.
  • Can develop a secondary infection not curable by this medication if using Macrodantin for an extended period.

Note: provides accurate and independent information prescription pills, over-the-counter medicines and natural products. This material is provided for educational purposes only and is not intended for medical advice, diagnosis or treatment. If you have questions about  dosage, or Macrodantin side effects, please contact your healthcare provider.