Pharmacokinetic Profiling of Fosfomycin and Nitrofurantoin to Optimize the Treatment of Uncomplicated Urinary Tract Infections

In our study, we investigated the amounts excreted in the bladder of nitrofurantoin and fosfomycin-trometamol to determine whether these two antibiotics are currently being used optimally in daily clinical practice in the treatment of cystitis. We were curious about this because clinical practice shows that not every patient suffers from cystitis after treatment with one of the two drugs.

With this research we want to optimize the effectiveness of the treatment and we also focussed on the prevention of resistance to nitrofurantoin and fosfomycin among microorganisms.

We concluded that there are very large differences between the amounts of antibiotics in the urine between patients and that the patient's urinary rhythm has a major influence. It seems that the amount of antibiotic in the bladder decreases when one goes to the toilet more often. This would, in theory, have an unfavourable effect on the effectiveness of the treatment. Treatment failure with fosfomycin appears to be more related to the resistance of microorganisms while the failure of therapy with nitrofurantoin is more related to low levels of the drug in the bladder. The mechanism of absorption into the blood and excretion into the bladder of nitrofurantoin is complex because it cannot be directly predicted based on the administered dose. More research is needed to investigate this mechanism so that this knowledge can be used to minimize the chance of treatment failure.