Nitrofurantoin

General information about nitrofurantoin

All nitrofurantoin products were approved by national authorities, leading to divergent information in the Summary of Product Characteristics (SPC) across Europe, some originated many decades ago. Dosage recommendations and indications vary widely  and would need to be based on updated knowledge.

Approved Information based on current Nitrofurantoin SPCs in Europe across Europe.

Indications

Despite the lack of clinical evidence some SPCs include indications beyond lower urinary tract infections such as pyelonephritis (not restricted to mild infections) or prostatitis. As systemic concentrations and concentrations in tissues don’t provide effective drug exposure such indications urgently need to be revised.

In some countries the usage of nitrofurantoin over long periods of time is controversially discussed and new reliable studies are needed to explore exposure/efficacy and exposure/toxicity relationships to define the risk/benefit ratio for indications other than short-term treatment of uncomplicated acute cystitis.

Safety

It is widely known that severe, though rare pulmonary side effects (diffuse interstitial pneumonitis or pulmonary fibrosis, or both) may occur in patients on prolonged treatment with high doses or treating patients with impaired kidney function. Most publications depend on single case reports and indicate a correlation with long-term treatment. This aspect is covered insufficiently in many SPCs that have not been scientifically updated since decades. Despite this accumulated knowledge most SPCs do not include a boxed warning and list prolonged treatment as a main indication.

Dosage recommendations

Dosages for acute infections vary from 150mg to 400mg daily and for long-term usage from 50mg-200mg daily. The daily dose is divided into 2-4 doses depending on the formulation.

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