Nitrofurantoin

C. diff Risk

Low

Oral Bioavailability

Moderate

Approximate Cost

$1/day

Dosing

50-100 mg PO q6h
100 mg PO q12h (MacroBID® formulation)

Contraindicated in infants < 1 month of age.

Use is contraindicated in CrCl< 40-60 mL/min. Renally cleared, requires dosage adjustment with changes in renal function. Consult a pharmacist for renal dosing

General Information

Common Usage

Uncomplicated cystitis in patients with normal renal function.

Does not provide adequate renal concentrations for treatment of systemic infections (i.e urosepsis, pyelonephritis); appropriate for cystitis and/or urinary prophylaxis.

Drug Monitoring

Monitor liver and renal function and pulmonary function (with long term use). CBC for hemolytic anemia.

Adverse Effects

  • Nausea (decreased if taken with food)
  • Hemolytic anemia if G6PD-deficient
  • Peripheral neuropathy
  • Interstitial pneumonitis and fibrosis with prolonged use (> 6 months)

Oral Liquids

Concentration: 10 mg/mL (compounded)
Taste: palatable
Not all strengths of oral liquids are listed nor are available on IWK formulary

Tablet/Capsule Strengths

50 mg tablet
100 mg capsule Nitrofurantoin Monohydrate Macrocrystals (MacroBID®)

Tablets and capsules are preferred especially over an unpleasant tasting liquid.
Not all strengths of oral tablets/capsules are listed and they are not all available on the IWK formulary

Additional Information

Does not provide adequate renal concentrations for treatment of systemic infections (i.e urosepsis, pyelonephritis); appropriate for cystitis and/or urinary prophylaxis.

Reduce dose in renal impairment or need for caution.

Contraindicated in infants less than 1 month of age (risk of hemolytic anemia), moderate-severe renal impairment, G-6-PD deficiency.

Do not use near term in pregnancy.

Pharmacology

Antimicrobial class: Nitrofuran

Average serum half life: No pediatric data.
Adults: 20 to 60 minutes and is prolonged with renal impairment

Route of Elimination: As metabolites and unchanged drug (40%) in the urine and small amounts in the bile; renal excretion is via glomerular filtration and tubular secretion