Answer
Adequate renal function is needed to deliver nitrofurantoin into urine. Impairment can reduce effectiveness and increase systemic adverse effects.
Sources for this answer
- NHS Specialist Pharmacy ServiceNHS Specialist Pharmacy Service · NHS medicine guidance
- Nitrofurantoin 50 mg tablets — Current selected SmPCemc · Summary of Product Characteristics
General medicine information. Follow the instructions for your own medicine and speak to a pharmacist or clinician about your individual circumstances.