Professional view

nitrofurantoin: prescribing and clinical use

Focused clinical detail for use alongside current product information, local policy and patient-specific assessment.

nitrofurantoin: clinical details

Prescribing considerations

Confirm organism susceptibility; Proteus, Serratia and Pseudomonas are generally resistant.
Low systemic and tissue concentrations make nitrofurantoin unsuitable for renal cortical or perinephric abscesses.
Check renal function against the product-specific SmPC. Selected SmPCs contraindicate renal dysfunction below 45 mL/minute but describe exceptional cautious use at 30–44 for selected resistant uncomplicated lower infections when benefit outweighs risk.
Use caution where pulmonary, hepatic or neurological disease could obscure toxicity, and in anaemia, diabetes, electrolyte imbalance, severe debility or vitamin-B deficiency.
Long-term use requires a clear continuing indication and heightened vigilance for pulmonary, hepatic, neurological and haematological toxicity.

Contraindications and cautions

Hypersensitivity to nitrofurantoin, other nitrofurans or relevant excipients
Product-defined significant renal dysfunction
Known G6PD deficiency
Acute porphyria
Infants younger than three months
Pregnancy during labour and delivery

Monitoring

Before treatment, consider eGFR, liver function, G6PD status and porphyria history.
During prolonged or repeated exposure, periodically review renal and liver function and ask about respiratory symptoms.
Stop and investigate suspected pulmonary, hepatic, neurological, haematological or haemolytic toxicity.
Nitrofurantoin can cause false-positive urine glucose results with reducing-substance methods.

Clinical pharmacology

Nitrofurantoin is reduced by bacterial enzymes to reactive intermediates that disrupt multiple cellular targets. Food improves oral absorption, circulating concentrations are low, and renal elimination produces useful urinary concentrations when kidney function is adequate.

Formulation and product differences

Standard tablets and hard capsules are distinct from prolonged-release capsules; instructions and age suitability are formulation-specific.
Selected hard capsules contain macrocrystalline nitrofurantoin, while the prolonged-release product combines nitrofurantoin microcrystals with nitrofurantoin monohydrate.
Selected products contain lactose; the prolonged-release product also contains sucrose.
The selected tablet's score line is not intended for breaking.