Nitrofurantoin is the first line (in the UK) prescription treatment available to treat uncomplicated urinary tract infections (including cystitis) in females. A short 3 day course is usually enough to completely clear an infection that otherwise would not clear without treatment. Nitrofurantoin is highly effective in treating UTIs. Symptoms should improve within two days of starting treatment. If your symptoms do not improve within this time or they worsen you should contact your doctor. Nitrofurantoin should not be used by people suffering with certain conditions or those using certain medications. You should always read the patient information leaflet (PIL) for Nitrofurantoin before taking this medication to ensure it is safe for you to use. Nitrofurantoin is now widely considered first line treatment in front of Trimethoprim. Trimethoprim is still a useful alternative to treat acute UTI in those who can not tolerate Nitrofurantoin.