II. Indications
- Conditions
- Uncomplicated Urinary Tract Infection
- For lower tract infections only (Bladder Infections)
- Does NOT cover Acute Pyelonephritis
- Urinary Tract Infection Prophylaxis
- Uncomplicated Urinary Tract Infection
- Activity
- Covers many urinary pathogens
- Does NOT cover Pseudomonas, Klebsiella, Proteus Serratia or Acinetobacter
III. Contraindications
-
Urine pH >8
- Associated with Nitrofurantoin resistance >40% (associated with protease species)
- See efficacy below
- G6PD Deficiency
- Prolonged use longer than 6 months
- Prolonged use >14 days in age over 65 years
- Relative contraindication if normal Renal Function >60 ml/min
-
Creatinine Clearance <30-40 ml/min
- Short-term use <14 days appears safe at GFR >30 ml/min
- Pregnancy after 36 weeks (or last 4 weeks of pregnancy)
- Risk of Hemolytic Anemia and Neonatal Jaundice
- References
- (2018) Presc Lett 25(8)
- Oplinger (2013) Ann Pharmacother 47(1):106-11 [PubMed]
IV. Mechanism
- Unclear mechanism, but may damage Bacterial DNA
V. Medications
- Macrobid
- Capsules: 100 mg
- Nitrofurantoin
- Capsules: 25 mg, 50 mg, 100 mg
- Suspension: 25 mg per 5 ml
VI. Dosing: Adult
- Take immediately after food to increase absorption (decreases gastrointestinal upset)
- Uncomplicated Urinary Tract Infection
- Nitrofurantoin
- Take 50 to 100 mg orally four times daily for 7 days (or 3 days after urine sterile)
- Macrobid (age >12 years old)
- Take 100 mg orally twice daily for 5 days
- Course: 5 days (instead of 7) is sufficient for uncomplicated UTI in non-pregnant women
- Nitrofurantoin
-
Urinary Tract Infection Prophylaxis (avoid use >6 months)
- Nitrofurantoin: Take 50 to 100 mg orally at bedtime
VII. Dosing: Child
- Avoid in age <1 month old (Risk of Hemolytic Anemia and Neonatal Jaundice)
- Take immediately after food to increase absorption (decreases gastrointestinal upset)
- Uncomplicated Urinary Tract Infection
- Nitrofurantoin
- Give 5-7 mg/kg/day divided four times daily orally for 7 days (or 3 days after urine sterile)
- Maximum: 100 mg/dose
- Macrobid (age >12 years old): 100 mg orally twice daily for 7 days
- Nitrofurantoin
-
Urinary Tract Infection Prophylaxis
- Give 1 mg/kg/day divided orally once to twice daily
VIII. Adverse Effects
- Common
- Nausea and Vomiting
- Decreased with longer acting preparation (Macrobid)
- Urine Color change
- Urine may appear brown
- Nausea and Vomiting
- Serious
- Pulmonary fibrosis (with chronic Nitrofurantoin use)
- Acute Nitrofurantoin Pulmonary Toxicity
- Avoid in eGFR <30 to 40 ml/min
- Avoid longterm use in eGFR <60 ml/min
- Neuropathy
- Hepatotoxicity
- Monitor Liver Function Tests with longterm use
IX. Efficacy
- Very high efficacy in lower Urinary Tract Infections (resistance to typical coliforms is <2%)
- However Nitrofurantoin resistance rises to >40% when Urine pH >8
X. Safety
-
Lactation
- Considered safe in Lactation after first month of life (unless maternal G6PD Deficiency)
- Pregnancy
- Considered safe in first 2 trimesters
- Avoid after 36 weeks or last 4 weeks of pregnancy
- Risk of Hemolytic Anemia and Neonatal Jaundice
XI. Resources
- Nitrofurantoin Capsules (DailyMed)
- Nitrofurantoin Suspension (DailyMed)
- Nitrofurantoin Monhydrate or Macrobid (DailyMed)
Images: Related links to external sites (from Bing)
Related Studies
| nitrofurantoin (on 12/21/2022 at Medicaid.Gov Survey of pharmacy drug pricing) | ||
| NITROFURANTOIN MCR 100 MG CAP | Generic | $0.38 each |
| NITROFURANTOIN MCR 25 MG CAP | Generic | $3.49 each |
| NITROFURANTOIN MCR 50 MG CAP | Generic | $0.35 each |
| NITROFURANTOIN MONO-MCR 100 MG | Generic | $0.41 each |