Nitrofurantoin (Macrobid): Uses, Warnings, and More
Quick summary Nitrofurantoin is an antibiotic used for certain urinary tract infections, especially acute cystitis. Brand names mentioned in the source include Macrobid, Macrodantin, and Furadantin. Medical disclaimer: This article is for general information...
This content is for educational purposes only and does not replace medical advice, diagnosis or treatment from a qualified healthcare professional.
Quick summary
Nitrofurantoin is an antibiotic used for certain urinary tract infections, especially acute cystitis. Brand names mentioned in the source include Macrobid, Macrodantin, and Furadantin.
Medical disclaimer: This article is for general information only. It does not replace advice from a doctor, pharmacist, or the official product leaflet. Do not use this page to diagnose a condition or to decide on treatment changes.
What is nitrofurantoin?
Nitrofurantoin is a medicine used to treat urinary tract infections. The source content identifies the product ingredients as nitrofurantoin monohydrate and nitrofurantoin sodium.
Brand names listed in the source include Macrobid, Macrodantin, and Furadantin.
How nitrofurantoin works
The source describes nitrofurantoin as a bactericidal medicine. It interferes with bacterial enzymatic processes involved in cellular respiration, carbohydrate metabolism, and cell wall synthesis.
Uses and therapeutic indications
According to the source, nitrofurantoin is used for acute cystitis in girls, adolescents, and adult women.
It is important to confirm the exact indication with a healthcare professional and the official leaflet, since use depends on the type of infection and the patient’s clinical situation.
How it is taken
The source states that nitrofurantoin is taken orally.
It also notes that it is recommended to take it during meals or with a glass of milk.
Dosage information from the source
| Group | Source information |
|---|---|
| Adults | 50–100 mg every 8 hours |
| Girls over 6 years and adolescents 12 to under 18 years | 5–7 mg/kg/day in 4 doses, maximum adult dose |
| Girls over 3 months | 1–2 mg/kg every 6 hours, maximum adult dose |
| Duration | 5–7 days |
Always verify the prescribed dose, formulation, and duration with the official instructions for the specific product.
Who should not use it, according to the source
The source lists the following contraindications:
- Hypersensitivity to nitrofurantoin or other nitrofurans
- Prolonged, continuous, or intermittent treatments longer than 7 days
- Renal failure with creatinine clearance below 45 mL/min
- Acute porphyria
- G6PD deficiency
- Last 2 weeks of pregnancy
- Children under 3 months
Warnings and precautions
The source says nitrofurantoin is not indicated for:
- Prophylactic treatment of recurrent urinary tract infections
- Male urinary tract infections
- Upper urinary tract infections
- Bacteremia or sepsis secondary to urinary infection
It also advises caution in people with renal insufficiency, lung disease, liver impairment, a tendency to allergic reactions, anemia, diabetes mellitus, electrolyte imbalance, weakness, or vitamin B deficiency, especially folic acid deficiency.
The source notes that treatment should be interrupted if hepatic changes, pulmonary symptoms, hypersensitivity symptoms, or neurological symptoms such as paresthesias appear.
It also mentions that nitrofurantoin may cause false-positive urine glucose test results.
Liver and kidney considerations
Liver failure: caution is advised.
Kidney failure: the source lists renal insufficiency with creatinine clearance below 45 mL/min as a contraindication, and creatinine clearance 30–44 mL/min as a situation requiring caution.
Interactions mentioned in the source
| Interaction | Source note |
|---|---|
| Food and agents that delay gastric emptying | Increased absorption |
| Some antacids, such as magnesium trisilicate | Decreased absorption; spacing of 2 hours is noted |
| Probenecid and sulfinpyrazone | Decreased renal excretion |
| Quinolones | Antagonistic effect |
| Acetazolamide, dichlorphenamide, potassium citrate, sodium bicarbonate | Decreased action |
If you take other medicines, the official leaflet or a pharmacist can help check for interactions.
Pregnancy and breastfeeding
Pregnancy: the source states that nitrofurantoin is contraindicated in the last two weeks of pregnancy because of the risk of fetal hemolytic anemia.
Breastfeeding: the source says nitrofurantoin appears in small traces in breast milk. It should be avoided in mothers of infants under 3 months of age, and also in infants over 3 months with suspected or diagnosed red blood cell enzyme deficiencies such as G6PD deficiency.
Driving and daily activities
The source notes that nitrofurantoin may cause dizziness. If dizziness occurs, extra care is needed with driving or other tasks that require alertness.
Possible adverse reactions and side effects
The source lists the following adverse reactions:
- Allergic skin reactions such as itching and hives
- Pseudo-lupus manifestations such as fever, chills, and joint pain, sometimes with pulmonary symptoms
- Angioedema
- Dizziness
- Peripheral neuropathies, especially with overdose, reduced renal elimination, diabetes, alcoholism, advanced age, or prolonged treatment
- Nausea, vomiting, abdominal pain, and diarrhea
The source also reports pharmacovigilance observations including interstitial nephritis, hepatitis, autoimmune hepatitis, cholestatic jaundice, chronic active hepatitis, hepatic necrosis, and cutaneous vasculitis.
What to verify with a doctor or pharmacist
If nitrofurantoin is prescribed or being considered, it is sensible to confirm the following with a healthcare professional:
- Whether the infection type matches the medicine’s intended use
- The correct formulation and dosing schedule
- Kidney function and whether it affects suitability
- Pregnancy or breastfeeding considerations
- Possible interactions with antacids, urinary alkalinizers, or other medicines
- Which symptoms should prompt urgent medical review
Safety reminder
Do not use this information to self-treat a urinary infection. Seek medical advice if symptoms are severe, unusual, recurrent, or not improving as expected. Always follow the official leaflet and the instructions given by your prescriber.
Frequently asked questions
▸ What is nitrofurantoin used for?
The source says it is used to treat urinary tract infections, especially acute cystitis in girls, adolescents, and adult women.
▸ What are the brand names mentioned in the source?
The source lists Macrobid, Macrodantin, and Furadantin.
▸ Should nitrofurantoin be taken with food?
The source recommends taking it during meals or with a glass of milk.
▸ Is nitrofurantoin used for all urinary infections?
No. The source says it is not indicated for upper urinary tract infections, bacteremia, sepsis secondary to urinary infection, male urinary tract infections, or prophylaxis of recurrent urinary tract infections.
▸ What side effects are listed in the source?
The source lists skin allergy reactions, dizziness, digestive symptoms, neuropathy, and several liver-related reactions among reported adverse effects.
▸ Where can I check the official information?
The FDA medication guide and the product’s official leaflet are the best places to confirm approved uses, warnings, and instructions.
Medical disclaimer
This content is for educational purposes only. It should not be used as a substitute for professional medical advice, diagnosis or treatment. Always ask a doctor, pharmacist or qualified healthcare professional before starting, stopping or changing any medicine.
Sources and verification
The following sources or official references are listed to support verification of the medicine information discussed in this article.
Medicine information can change and may vary depending on country, product formulation, patient history and professional guidance. Always check official medicine information and ask a healthcare professional for personal medical questions.