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Nitrofurantoin – Effect, Application & Risks


An antibiotic drug is called nitrofurantoin . The drug is used to treat bacterial urinary tract infections .

What is nitrofurantoin?

Nitrofurantoin is a synthetic nitrofuran derivative that is classified as a chemotherapeutic agent. It is suitable for the treatment of bacterial urinary tract diseases and has been the drug of first choice since 2011.

Nitrofurantoin requires a prescription and can only be purchased by prescription.

Research into a nitrofuran-type antibiotic that can be produced chemically began as early as the 1940s. As a result, nitrofurantoin was finally discovered. From the 1950s, the antibiotic was used to combat urinary tract infections. In Germany, generic drugs containing nitrofurantoin are also used.

Pharmacological action

Nitrofurantoin is one of the so-called prodrugs. This means that its conversion into its active form only takes place in the urinary tract . Bacterial enzymes are responsible for this conversion . They become active after the active substance has been absorbed into the blood .

The antibiotic has the property of penetrating the bacteria that cause the urinary tract infection. Within the bacterial cells, nitrofurantoin is converted into the therapeutically active form (by nitroreductases). By attacking the genome of the bacteria, the germs can ultimately be rendered harmless. In addition, the metabolic enzymes that are vital for the bacterial cells are specifically destroyed.

The active form of nitrofurantoin has different points of attack on the bacterial cells. In this way, it is very rare for resistance to the antibiotic. Furthermore, nitrofurantoin has the advantage that the drug not only inhibits the growth of bacteria, but also kills the germs selectively. Therefore, nitrofurantoin is considered a bactericidal antibiotic.

The chemotherapeutic agent is effective against types of bacteria such as staphylococci , enterococci , Escherichia coli , enterobacter and Klebsiella . However, due to natural resistance, nitrofurantoin has no effect on Proteus bacteria, Pseudomonas aeruginosa , Morganella morganii and Provicencia bacteria.

Nitrofurantoin reaches its highest level in urine about 4 to 5 hours after its administration. Around 50 percent of the antibiotic is converted into ineffective metabolites, which are also excreted in the urine. A harmless side effect is the brown discoloration of the urine.

Medical Application & Use

Nitrofurantoin is used for uncomplicated acute inflammation of the urinary bladder . Uncomplicated infections are diseases that progress without fever , discharge, vaginal itching , pain in the back or kidneys , nausea and vomiting .

Nitrofurantoin is sometimes also suitable for prevention if there is a narrowing of the urinary tract or if the urinary tract infections recur frequently. If it is an acute urinary tract infection, the treatment usually lasts 5 to 7 days. In the case of prevention, the length of therapy can last up to six months. However, the dosage is lower.

Nitrofurantoin is taken in three to four individual doses in the form of capsules of 100 milligrams each. If sustained-release capsules are administered with a delayed release of the active ingredient, the dose is two to three capsules. The medication is taken every six to eight hours with a meal and some water.

In the case of an acute infection, nitrofurantoin must be given for as long as the doctor has prescribed. This also applies if the symptoms improve. When nitrofurantoin is given for prevention, the patient usually takes one pill at bedtime, after the last urination.

Risks & side effects

As with other antibiotics, taking nitrofurantoin can cause unwanted side effects. Around ten percent of all patients suffer from allergic reactions such as skin rashes , redness , itching and edema , impaired movement coordination , tremors in the eyes and dizziness . The doctor treating you should be informed quickly of any allergic reactions.

About one in ten to one hundred patients also suffer from side effects such as loss of appetite , cough , chest pain , nausea, vomiting and headache . Only very rarely do drug fever, ear salivation , anemia , liver inflammation or liver damage occur.

If nitrofurantoin is taken for more than a year, older women often develop pneumonia . In addition, lung tissue is transformed into connective tissue , which can sometimes have life-threatening consequences. The BfArM (Federal Institute for Drugs and Medical Devices) therefore advises against long-term treatment with nitrofurantoin.

Nitrofurantoin should not be used if the patient suffers from inflamed nerves , urinary retention or dribbling , a deficiency in the enzyme glucose-6-phosphate dehydrogenase or kidney diseases. In the case of allergies , pulmonary fibrosis , bronchial asthma or liver inflammation, the risk and benefit of taking nitrofurantoin must be carefully weighed up.

During pregnancy , nitrofurantoin may only be used in the first six months if the doctor has carefully weighed up the risk and benefit. In the final phase of pregnancy, antibiotics should generally not be taken. Nitrofurantoin can cause anemia in babies. If the mother is taking nitrofurantoin, the child should not be breastfed if a glucose-6-phosphate dehydrogenase deficiency is suspected.

The positive effect of nitrofurantoin can be impaired by interactions when taking other medications at the same time. These include the antibiotic nalidixic acid, stomach acid protectants containing magnesium, the gastric drug propantheline bromide, and the gout drugs sulfinpyrazone and probenecid . These reduce the effect of nitrofurantoin and increase undesirable side effects.

Lisa Newlon
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Hello! I am Lisa Newlon, and I am a medical writer and researcher with over 10 years of experience in the healthcare industry. I have a Master’s degree in Medicine, and my deep understanding of medical terminology, practices, and procedures has made me a trusted source of information in the medical world.