Medical description: Nitrofurantoin is an antibiotic drug used primarily for the treatment of bladder infections. In general, the medicine is active against Gram-positive and Gram-negative bacteria, but susceptibility study is preferable before starting the treatment. The medicine can be used in children older than one month, but is not advised during the last 3 months of pregnancy and during breastfeeding. General dosage of the drug is 50 mg or 100 mg taken for 4 times a day during a 7-day treatment course.
Synonyms: Uritop, Alfuran, Cyantin, Cystit, Furadantin, Furadonin, Furan, Furina, Nitrex, Nitrofan, Phenurin, Urantoin, Welfurin
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Nitrofurantoin is a medicine with a pronounced antimicrobial action. It makes a part of Nitrofurans, a class of antibiotic and antibacterial drugs. The medicine is commonly used for the urinary tract infections, for example, bladder infections, except kidney infections such as pyelonephritis. It is also not advised for prostatitis and intra-abdominal abscesses treatments as it provides lesser effect due to the decreased tissue penetration and low blood levels.
For the first time the medicine was used in 1953. Nitrofurantoin is included in the List of Essential Medicines by World Health Organization meaning that it is one of the most important drugs required in a basic health care system. In the United States of America, the medicine is sold as Macrobid. Different countries and manufacturers offer identical medicines called in the USA the generic versions of Nitrofurantoin. The cost of a treatment course with the American version of the drug is around 60 Dollars for 10 days. The cost of the generic version treatment course varies from 7 to 20 Dollars for a ten-day course.
Nitrofurantoin - Mode of action
The mechanism of Nitrofurantoin action is quite complex. Unlike most antibiotics, the medicine slows down the development and growth of bacteria rather than eliminates already existing cells. Nitrofurantoin damages bacterial DNA without negatively affecting healthy human cells because bacterial cells faster start the reaction with the medicine’s main component. Nitrofurantoin reacts with the bacterial DNA and RNA, providing double simultaneous effect. To date, it is not precisely known which of the actions provide bacteriostatic effect. However, it is known that its versatile mechanism of action is responsible for the low rate of resistance development to the medicine in bacteria.
Pharmacokinetics of Nitrofurantoin
When the medicine is used orally, it is well absorbed from the gastrointestinal tract reaching the bioavailability of 90%. The bioavailability is increased when Nitrofurantoin is taken with meal. The speed of absorption depends on the size of crystals – the smaller they are, the faster is the absorption. The peak concentration in tissues in the intake of 100 mg is lower than 1 μg/ml. The medicine is metabolized in liver and muscle tissue. It crosses the placenta and the blood-brain barrier, excreted in breast milk. Total urinary excretion is 40%, unchanged are exerted 25%. The concentration in the urine may reach 200 μg/ml or more. The medicine provides bacteriostatic effect on all the susceptible infections causing cystitis at as small concentrations as 32 μg/ml. The penetration in the tissues of Nitrofurantoin is very poor; therefore, the drug is not used to treat kidneys.
The release form of Nitrofurantoin
The medicine is supplied in form of pills, suspension, and gelatin capsules of 25mg, 50mg, and 100mg.
Dosages of Nitrofurantoin
The dosage for adults for acute infection is 50 to 100 mg orally 4 times a day for 7 days or for at least 3 days after urine sterility is found during the urine test. Prophylaxis of cystitis requires the intake of 50 to 100 mg orally once a day at bedtime. The length of the treatment course depends on the severity of the infection and frequency of relapses and can take from 3 to 12 months.
The dosage of Nitrofurantoin for children over one month of age is 5-7 mg per kilogram of body weight daily (up to 400 mg a day) taken orally in 4 intakes at even intervals.
The prophylaxis of cystitis in children requires the administration of 1-2 mg per kilogram of weight daily (up to 100 mg a day) orally in 1 to 2 intakes at even intervals.
When Nitrofurantoin is prescribed
Nitrofurantoin is effective against Gram-positive and Gram negative bacteria affecting bladder such as Streptococcus spp., Staphylococcus spp., Shigella flexneri, Shigella dysenteriae, Shigella boydii, Shigella sonnei, Streptococcus agalactiae, Staphylococcus saprophyticus, Escherichia coli, Proteus spp., Klebsiella, Enterococcus faecalis, Citrobacter, and Coagulase negative staphylococci. Preferably, the medicine is prescribed after susceptibility test confirming that the bacteria that caused the disease is sensible to the drug.
Commonly, the Nitrofurantoin and other medicines with the same composition are prescribed for cystitis, pyelitis, and urethritis. Rarely, for pyelonephritis. It is also used to prevent infection in surgical intervention with the urinary tract or examinations such as cystoscopy, catheterization, and so on.
The medicine is considered ineffective against majority strains of the following bacteria: Enterobacter, Klebsiella, Proteus, and Pseudomonas.
Interactions of Nitrofurantoin with other medicines
The simultaneous use of nalidixic acid or antacids comprising magnesium trisilicate with Nitrofurantoin reduces antibacterial effect. The medicine is incompatible with fluoroquinolones. The medicines that block tubular secretion decrease the antibacterial effect (by reducing the concentration of nitrofurantoin in urine) and increase toxicity (increased concentrations of the medicine in blood).
Contraindications for Nitrofurantoin use
The medicine is contraindicated to people allergic to one or more of its components, children less than one month of age, during last trimester of pregnancy, during breastfeeding, to people suffering from oliguria, anuria, or significant renal insufficiency, liver cirrhosis, and chronic hepatitis.
Though the medicine is not recommended in the last trimester of pregnancy, in Australia, the medicine is believed to be safe throughout the entire pregnancy. In the USA the drug is attributed pregnancy category B, meaning that the studies performed hadn’t show any evidence that the medicine is harmful during the non-human studies.
Adverse effects of Nitrofurantoin
Nitrofurantoin potentially may cause a range of side effects such as chest pain, fever, chills, cough, general feeling of discomfort or illness, hives, itching, joint or muscle pain, skin rash, troubled breathing, black stools, headache, dizziness, and others. In occurrence of any of the discomfort during the medicine intake, contact your doctor or emergency right away.
Nitrofurantoin is a medicine with a pronounced antimicrobial action.
The medicine is commonly used for the urinary tract infections.
Infections of the urinary tract are treated either by broad-spectrum antibiotics or specific antibacterial drugs that show exceptional effect namely in the elimination of bladder or kidney infections. One of such drugs is Nitrofurantoin or its generic analogs. The medicine is mostly effective in cystitis and urethritis but not pyelonephritis as its higher concentrations are found in urine rather than tissues. The bioavailability of the medicine, i.e. the quantity of active substance reaching the site of infection, is 90%. In acute cystitis or other bladder inflammations, adults are prescribed 50-100 mg of Generic Nitrofurantoin in capsules taken orally 4 times a day for a week. If the symptoms disappear faster, the medicine still needs to be used for the following 3 days in order to prevent relapse of the disease. For the prophylaxis of bladder infections, the drug is used from 3 to 12 months in amount of 50-100 mg once a day before bedtime.
The use of Nitrofurantoin or Generic Nitrofurantoin in children is calculated based on the body weight. The daily dosage should consist of 5-7 mg per kilogram of the child’s weight and must be divided in 4 intakes. Prophylaxis of bladder infections in children requires the daily dosage of 1-2 mg per kilogram of the child’s weight divided in 2 intakes.
The general treatment dosage can be administered after a urological surgery or catheterization in order to prevent infection development.
Contraindications for use
Generic Nitrofurantoin is considered a relatively safe drug as it can be used even in children of one month of age. However, it can be dangerous for people with allergy to one of its components, during last trimesters of pregnancy, people with cirrhosis or chronic hepatitis, and severe kidney dysfunction.
Where to buy Generic Nitrofurantoin?
In the USA, UK, Australia, and Canada the medicine is released only with a prescription. Other countries that have less rigid legislation allow selling the drug over-the-counter. If you are suffering from chronic bladder infection and do not want to go to a doctor for a prescription or have an already expired prescription, you can buy Nitrofurantoin at an international online pharmacy. Such pharmacies are commonly situated in the countries where drugs can be bought without a prescription, so you can legally purchase the drug you need without seeking assistance of local illegal drug sellers.
Even if you have a prescription, it’s still more convenient to buy the drug online. If you opt for Generic Nitrofurantoin, you can save more than a half of the treatment cost.
Tips on how to buy Generic Nitrofurantoin online safely
First of all, look for a reliable seller with adequate prices. Check at least 5 online pharmacies in order to know the average price for Generic Nitrofurantoin pills of the dosage that you need. If you see a significantly lower price, be aware that the drug may be expired and harmful or ineffective.
Before purchasing the medicine, you need to make sure that it is not contraindicated to you. Check the list of contraindications and negative interactions with other medicines. If you have problems with liver or kidneys, make sure to consult your doctor on the dosage adjustment.
Like any other medicine, Generic Nitrofurantoin pills may cause various adverse effects. Be ready to experience them and immediately stop the intake. If even after you stopped using the medicine the negative reactions are still there, seek medical assistance.
Respect the dosage regimen chosen by your doctor. If you skipped the dose, take it as soon as you remembered. If you are not sure whether you took the last dosage or missed it, skip the intake and take the drug when the next intake is scheduled.