Nitrofurantoin is the name given to an antibiotic drug. The drug is used for the treatment of bacterial urinary tract infections.
What is nitrofurantoin?
Nitrofurantoin is the name given to an antibiotic drug used for the therapy of bacterial urinary tract infections. Nitrofurantoin is a synthetic nitrofuran derivative that is classified as a chemotherapeutic agent. It is suitable for the treatment of bacterial urinary tract infections and has been considered a first-line agent since 2011. Nitrofurantoin is available by prescription only. Research into a nitrofuran-type antibiotic that could be produced chemically began as early as the 1940s. As a result, the discovery of nitrofurantoin eventually occurred. 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 counted among the so-called prodrugs. This means that its conversion to its active form occurs only 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 trigger the urinary tract infection. Within the bacterial cells, the conversion of nitrofurantoin into the therapeutically active form takes place
(by nitroreductases). By attacking the genetic material 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 various 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 the bacteria, but also selectively kills the germs. Therefore, nitrofurantoin is considered a bactericidal antibiotic. The chemotherapeutic agent exerts its effect against bacterial species such as Staphylococcus, Enterococcus, Escherichia coli, Enterobacter and Klebsiella. However, nitrofurantoin is not effective against Proteus bacteria, Pseudomonas aeruginosa, Morganella morganii and Provicencia bacteria due to natural resistance. Nitrofurantoin reaches its highest level in urine about 4 to 5 hours after its administration. About 50 percent of the antibiotic is converted to ineffective metabolites, which are also excreted in the urine. A harmless side effect is the brownish discoloration of the urine.
Medical use and application
The area of application for nitrofurantoin is uncomplicated acute inflammation of the urinary bladder. Uncomplicated infections are those without fever, discharge, vaginal itching, pain in the back or kidneys, or nausea and vomiting. Nitrofurantoin is sometimes also suitable for prevention if there is stenosis of the urinary tract or if the urinary tract infections recur frequently. If it is an acute urinary tract infection, the treatment period is usually 5 to 7 days. In the case of prevention, the length of therapy can last up to six months. However, the dosage is lower in this case. Nitrofurantoin is taken in three to four individual doses in the form of capsules of 100 milligrams each. If sustained-release capsules are administered, the dose is two to three capsules. The medication is taken every six to eight hours as part of a meal with some water. In the case of an acute infection, nitrofurantoin must be administered for as long as the doctor has prescribed it. This also applies if the symptoms improve. If nitrofurantoin is given as a preventive measure, the patient usually takes one tablet before bedtime, after the last urination.
Risks and side effects
As with other antibiotics, taking nitrofurantoin can result in unwanted side effects. For example, about ten percent of all patients suffer from allergic reactions such as rashes on the skin, redness, itching and edema, disturbances in 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 suffers from side effects such as loss of appetite, cough, chest pain, nausea, vomiting and headache. Very rarely, drug fever, parotitis, anemia, hepatitis, or damage to the liver occur. If nitrofurantoin is taken for more than a year, pneumonia often appears in older women. In addition, lung tissue is converted into connective tissue, which can have life-threatening consequences in some cases. Long-term treatment with nitrofurantoin is therefore not recommended by the BfArM (Federal Institute for Drugs and Medical Devices). Nitrofurantoin must not be used if the patient suffers from inflamed nerves, urinary retention or urinary dribbling, a deficiency of the enzyme glucose-6-phosphate dehydrogenase or kidney disease. Consistent weighing of the risks and benefits of nitrofurantoin administration must be done in the case of allergies, pulmonary fibrosis, bronchial asthma, or liver inflammation. During pregnancy, nitrofurantoin may be used in the first six months only if the physician has carefully weighed the risks and benefits. In the final phase of pregnancy, the antibiotic should generally not be taken. Nitrofurantoin can cause anemia in babies. During breastfeeding, the child must not be breastfed if the mother takes nitrofurantoin and is suspected of having a glucose-6-phosphate dehydrogenase deficiency. The beneficial effect of nitrofurantoin may be affected by interactions when other drugs are taken at the same time. These include the antibiotic nalidixic acid, magnesium-containing antacids, the stomachic propantheline bromide, and the gout medications sulfinpyrazone and probenecid. These reduce the effect of nitrofurantoin and increase undesirable side effects.
