Nitrofurantoin

As Nitrofurantoin is called an antibiotic drug. 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 first choice since 2011.

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

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

Pharmacological effect

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 is absorbed into the blood.

The antibiotic has the ability to penetrate the bacteria that cause the urinary tract infection. Nitrofurantoin is converted into the therapeutically active form within the bacterial cells (by nitroreductases). By attacking the genetic make-up 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, resistance to the antibiotic is very rare. Furthermore, nitrofurantoin has the advantage that the drug not only inhibits the growth of bacteria, but also selectively kills the germs. Therefore, nitrofurantoin is considered a bactericidal antibiotic.

The chemotherapeutic agent unfolds its effect against types of bacteria such as staphylococci, enterococci, Escherichia coli, Enterobacter and Klebsiellae. However, due to natural resistance, nitrofurantoin has no effect on Proteus bacteria, Pseudomonas aeruginosa, Morganella morganii or Provicencia bacteria.

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

Medical application & use

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

Nitrofurantoin is sometimes also suitable for prevention when there is a narrowing of the lower urinary tract or urinary tract infections recur frequently. If it is an acute urinary tract infection, the duration of treatment is usually 5 to 7 days. In the case of prevention, the duration 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 prolonged-release capsules are administered with delayed release of the active ingredient, the dose is two to three capsules. The medication is taken every six to eight hours as part of a meal with a little water.

In the case of an acute infection, nitrofurantoin must be administered for as long as the doctor has prescribed it. This also applies to an improvement in the symptoms. When nitrofurantoin is given as a preventive measure, the patient usually takes one tablet at bedtime, after the last urination.

Risks & side effects

As with other antibiotics, taking nitrofurantoin can cause undesirable side effects. Around ten percent of all patients suffer from allergic reactions such as rashes on the skin, redness, itching and edema, disorders of movement coordination, eye tremors and dizziness. The attending physician must be informed quickly of any allergic reactions.

About one in ten to one hundred patients also has side effects such as loss of appetite, cough, chest pain, nausea, vomiting, and headache. A drug fever, inflammation of the parotid, anemia, inflammation of the liver or damage to the liver occurs very rarely.

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

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

During pregnancy, nitrofurantoin may only be used in the first six months if the doctor has carefully weighed the risks and benefits. In the final phase of pregnancy you should generally refrain from taking the antibiotic. For example, nitrofurantoin can cause anemia in babies. During the breastfeeding period, if the mother is taking nitrofurantoin, the child must not be breastfed if he is suspected of having a glucose-6-phosphate dehydrogenase deficiency.

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