Until recently, use of nitrofurantoin was contraindicated in patients with an estimated glomerular filtration rate (eGFR) less than 60ml/min/1.73m2. However, the latest advice from the MHRA states that the drug can now be used in patients with an eGFR greater than 45ml/min/1.73m2.
Following a review of the evidence, the MHRA concluded that, in the context of increasing resistance of lower urinary tract pathogens to standard therapy and the risk of Clostridium difficile colitis associated with widespread use of alternative broad-spectrum antibiotics, the eGFR cut-off of 60ml/min/1.73m2 was no longer supported.
In certain instances nitrofurantoin may also be prescribed for patients with an eGFR of 30 to 44ml/min/1.73m2. Use in such patients should be limited to a short course of 3—7 days for the treatment of lower UTI with suspected or proven multidrug-resistant pathogens where the benefits of nitrofurantoin are considered to outweigh the risk of adverse effects.
Further information: MHRA Drug Safety Update, September 2014