Nitrofurantoin is an antibacterial agent that helps in fighting bacteria and treating the urinary tract . Nitrofurantoin is an antibiotic that prevents infection by killing the bacteria. Antibiotics like nitrofurantoin are not used for colds, flu or other viral functions.

  • Among many antibiotics, nitrofurantoin is a special and unique antibiotic which is characterised by a Hayden tone ring with her Nitro substituted for Anil chain and is metabolised within the bacteria to produce reactive compounds.
  • Nitrofurantoin is known for its effectiveness against most of the common uropathogens and is rapidly excreted from the urine.
  • Nitrofurantoin is not found suitable for the treatment of upper tract complicated infections and blood borne infections and has minimal effect on bowel residents and vagina flora.
  • Nitrofurantoin may cause gastrointestinal upset and pulmonary issues such as pulmonary fibrosis when taken for a long use.
  • It should be avoided by patients with GbPD ( glucose 6 phosphate dehydrogenase) deficiency as it can lead to haemolytic anemia.
  • Nitrofurantoin is also effective against a  certain class of bacteria called enterobacteriaceae .It acts as a mutagen that inhibits DNA synthesis.
  • Nitrofurantoin is known as a urinary antiseptic that is associated with hepatic injury as well.

Uses of the antibiotic nitrofurantoin

  • Nitrofurantoin is mostly used to try to prevent urinary tract infections.infections
  • It stops the growth of bacteria and hence the infection.
  • Nitrofurantoin is not used for infants especially below one month of age  due to increased risk of blood related problems such as haemolytic amoeba.
  • It is a good treatment option for the acute management of uncomplicated cystitis selectively within the elderly populations.
  • Nitrofurantoin is also used for some ranges of liver diseases such as acute hepatitis occasionally with the features of Cholestasis,  hepatic granulomas,  chronic hepatitis  along with autoimmune features and cirrhosis. However, the relative frequencies of hepatocellular and cholestatic or of acute and chronic hepatitis has been debated.
  • Nitrofurantoin is a synthetic , orally active and bactericidal agent mainly  associated with the treatment of urinary tract infections and where most of the urinary tract pathogens retain susceptibility to nitrofurantoin with rare resistance.
  • It is also suitable for the treatment of prophylaxis of urinary tract infections in elderly patients.
  • Certain acute respiratory reactions to nitrofurantoin include dyspnea , interstitial pneumonitis, pleural effusion . It may also cause acute lung injury more often than any other drug can cause.
  • Nitrofurantoin should not be used with substantial renal insufficiency which has creatinine clearance of below 60 ml per minute.
  • Nitrofurantoin can also be used in pregnancy up to a certain stage that appears to be safe; however, it is not suggested for a pregnant woman within 38 to 42 weeks of gestation period that can probably  initiate a possible risk of haemolytic anemia.
  • Nitrofurantoin is very active against gram positive cocci shaped bacteria and equally.

Dose of nitrofurantoin in general population

Dosage forms or strength of nitrofurantoin

  • 25 milligram
  • 50 milligram
  • 100 milligram

The dosage of nitrofurantoin depends upon several factors such as your age, the health conditions, severity of a complication, other medical conditions present in the body, reaction to your first dose etc.  The dosage completely varies from person to person and also it depends upon the strength and number of doses that the patient takes each day upon recommendation.

  • For oral dosage forms such as capsule suspension or tablets the adult or teenagers may take 50 to 100 milligrams at bedtime under medical consultation, if you have certain infections especially the urinary tract infections.
  • Children need medical supervision first and the dose  basically depends upon the body weight along with other factors.
  • For  infants below one month of age it is not recommended to have this medicine.

Dosage recommended for the treatment of urinary tract infections

  • Nitrofurantoin is a prescription drug that is available as an oral capsule and as an oral suspension. Oral capsules of nitrofurantoin are available as the brand name drugs as macrobid and Macrodantin but it is also available as the generic drugs.

child dosage (0-1 month) 

These drugs are not recommended by the medical health care specialist to be used in children younger than one month of age.

Child dosage one month to 11 years

  • The macrodantin is taken as 5 to 7 mg per kg of body weight per day into 4 divided doses where the treatment length may vary.
  • The macrobid drugs are not found suitable to be used in children below 12 years of age and these drugs are strictly avoided in these cases.

child dosage 12 years to 17 years

  • Macrodantin is used as 5 to 7 mg per kg of body weight taken into 4 divided doses a day.
  • Macrobid are  suggested to have 100 mg every 12 hours for 7 days continuously to track the infection.

Adult dosage 18 years to 64 years

  • Macrodantin is recommended to be taken as 50-100 mg four  times a day.
  • Macrobid can be taken  100 mg every 12 hours for 7 days continuously.

Dosage of older people over 65 years of age

  • The kidneys of older people are not very healthy and may not work well so , slow functioning of kidneys may cause drugs to process more slowly and as a result the drugs retained in the body for a longer time and eventually increases the risk of side effects.
  • However, lower  dosages are preferred or may switch to a different treatment schedule as this can help in lowering the levels of building up of these drugs in the body.

Dosage of nitrofurantoin for the prevention of urinary tract infections

  • Children below one month of age are  not recommended to use this medicine.
  • Children between one month and 217 years can have macrodantin as one mg per kg body weight once per a day whereas macrobid are not suggested for the prevention of urinary infections in children of these ages.
  • Adults above  18 years of age can have macrodantin of 50-100 mg usually at bedtime whereas macrobid are not used.
  • Senior citizens of higher age that are above  65 years of age are usually recommended lower doses of these drugs as their kidneys do not work well ,which they used to be and can’t filter out waste materials that raises the risk of some major side effects in the body.

Taking the drugs as directed in the prescription

Nitrofurantoin oral capsules are used for the short term treatment of related issues like urinary tract infections. Macrodantin may be used as the long term treatment options.

But under certain conditions the drugs comes out with some serious risk if you don’t take the medicines as prescribed, here are some of the mentioned ones

  • If you stop taking medicines are drugs suddenly by your own

Stopping the intake of medicines daily may increase your chances of spreading urinary tract infections and this may make the situation even more worse. If you do this then the bacteria may become resistant to this drug and will not work for you anymore.

  • If you don’t take the drug on scheduled time

Not taking the medicine on time prescribed increases your chances of infection and the bacteria becomes resistant to this drug and eventually stops working for you.

  • If you take too much drugs without recommendation

Consuming more and more drugs believing that it would function more, is one of the greatest myths and the patient can have dangerous levels of the drug in the body, also the overdose of this drug results in nausea and vomiting. Talk to your nephrologists or doctor ( as soon as possible to avoid any serious side effects.

Major side effects of Nitrofurantoin

The common side effects of Nitrofurantoin as a medications include :- 

  • Nausea 
  • Vomiting
  • Appetite loss.
  • Headache
  • Dizziness
  • Diarrhoea
  • Dark colour or brown colour urine. 

However, the common symptoms can be managed easily after consulting the nephrologist (

Serious side effects of Nitrofurantoin

Serious side effects are usually rare and need to consult a healthcare specialist as soon as possible.

The major side effects includes :-

  • Inflammation of lungs .

The inflammation of lung tissues may cause some symptoms such as tiredness, breath shortness, pain in chest , fever, chills and some serious painful coughs.

  • Liver complications

The side effects on the liver cause some other symptoms such as itching, yellowing of the skin, vomiting, dark coloured and foamy urine, and appetite loss. 

  • Damages in the nerves 

There can be nerve damage as well in such cases ,and the symptoms include numbness in the hands or feet or you may feel some tingling and muscle weakness as well.

  • Haemolysis or the red blood cell damages . The symptoms include pale skin, weakness or tiredness in the body.
  • Diarrhoea – Diarrhoea is quite serious for the patients , the symptoms include loose or watery stools, bloody stools, and stomach pain. 

Side effects of Nitrofurantoin on kidneys

  • Patients with renal impairments have reduced renal secretion of Nitrofurantoin and these may reduce antibacterial efficiency and increase its risk of side effects.
  • The side effects include nausea, vomiting, appetite loss, diarrhoea and in some cases it may also result in its failures in the treatment.

Major drug interactions of Nitrofurantoin

Nitrofurantoin oral capsules can interact with other medications , vitamins , minerals or other herbs that you take along with these medicines.

  •  An interaction happens to change the way a drug works. The drug interaction can come out to be sometimes harmful and sometimes helps in functioning well.
  • To avoid any drug interaction with nitrofurantoin firstly,  you should clearly mention all of your medications , so the  doctor or  nephrologists manage well to avoid any interactions.

The drug interactions that can happen with nitrofurantoin or the drugs that you should not take with nitrofurantoin includes:- 

  • Antacids like Gavison  which contain magnesium trisilicate-  taking these drugs with nitrofurantoin can make their functioning less effective.
  • Probenecid and sulfinpyrazone drugs. Intake of these drugs along with taking nitrofurantoin results into drug interaction and may cause harmful levels of nitrofurantoin to build up in and causes major side effects in the body
  • Intake of nitrofurantoin is generally avoided if you are having some allergic reactions otherwise it would lead to some trouble breathing ,swelling of throat or tongue. Knowing the allergic reactions and still taking the drugs can prove to be fatal.
  • People with severe renal impairment should generally limit taking these drugs as it would cause build-up of these drugs in the body.
  • Also, people with liver disease avoid taking these nitrofurantoin, as it can make your liver damage worsen.
  • The pregnant women of increased weeks of gestation period that is 32 to 42 weeks of gestation need consultation first before taking this medicine into the body. Nitrofurantoin is considered as a category B drug that means no sufficient research has been made showing risk to the foetus when mother takes this drug.
  • Women who breastfeed should consult their doctor before taking nitrofurantoin.

Is nitrofurantoin a good antibiotic to take?

Yes, nitrofurantoin is a good antibiotic recommended by the health care specialist to treat urinary tract infections. It is effective against a wide array of bacteria such as enterobacter cystitis,, Klebsiella , enterococcus, Staphylococcus aureus and avoids infections caused by different types of bacteria. The other preferred antibiotics of UTI  include sulfamethoxazole and fosfomycin.

Is nitrofurantoin the same as amoxicillin?

Nitrofurantoin amoxicillin are both antibiotics but are not actually the same.  Amoxicillin is a good and cheap antibiotic that is available in different forms to treat various types of  bacterial infections. It is used to prevent urinary tract infection and is also used for treating infections of the skin, lungs ,eyes ,ears, nose and throat. Whereas, nitrofurantoin antibiotics are known to treat urinary tract infection. The antibiotics which are similar to nitrofurantoin that are alternatives compared include cipro, sulfamethoxazole ,Bactrim, amoxil amoxicillin and doxycycline.

Why is it recommended to take nitrofurantoin at night?

It is recommended to take nitrofurantoin at night because taking the  nitrofurantoin oral capsule may cause drowsiness. It is best taken with food or milk to avoid and lessen  stomach upset and easily help your body to absorb the medicine. Dosage of nitrofurantoin needs space evenly throughout your day for example, if you take twice a day, then space the dose for 12 hours at least. So , the best recommended timing lies one in the morning and another at night. So avoid taking this medicine in an empty stomach to prevent stomach upset rather prefer  it with the food and is  recommended to take during bedtime especially.

How fast does nitrofurantoin work?

Nitrofurantoin generally starts working within 3 to 5 days, although it sometimes takes a week to clear symptoms. The UTI infection starts fading away from 2 to 3 days after starting your antibiotics. But taking the medications to the full course is very important to make it an effective treatment and ensure that infection fades away completely. However, most people start to feel relief from the pain within 2 to 3 days after intake of medicines is scheduled.

 What is the Nitrofurantoin prophylaxis dose for children?

Nitrofurantoin is frequently recommended as prophylaxis for recurrent urinary tract infections. Nitrofurantoin remains the first choice as antimicrobial for an uncomplicated unity tract infection due to low resistance rates among the uropathogens. Nitrofurantoin as prophylaxis are  used for years for most of the time ,but the  Dutch guidelines advise to not to use nitrofurantoin for more than 12 months because prolonged use may link with severe adverse situations such as pulmonary toxicity. A daily dose of 50 mg of nitrofurantoin as prophylaxis is generally recommended for children suffering from urinary tract infections.

 What is the Nitrofurantoin prophylaxis dose for adults? 

Nitrofurantoin as prophylaxis can be dosed as 50 to 100  mg orally once a day at bedtime or twice a day but under commendable conditions.

 What is the Nitrofurantoin prophylaxis dose in urinary tract infections? 

Nitrofurantoin is used in urinary tract infections and is taken as oral dosage forms such as capsule ,suspension tablets as 50 to 100 mg at bedtime. Dose may vary depending upon your body weight and this is decided by the doctors . so you should not decide this by your own and must consult their doctors(

Is nitrofurantoin known to be safe for chronic kidney disease patients?

Nitrofurantoin is commonly used to try to prevent urinary tract infections caused by bacteria but it is not recommended  to patients with an estimated kidney global filtration rate below 60 ml per minute 1.73 metre square. Nitrofurantoin use can prove to be problematic for people suffering from Renal dysfunction as it can lead to the toxicity because of an increased nitrofurantoin serum levels, also the renal dysfunction reduces the efficacy of nitrofurantoin as an antimicrobial medicine. Taking nitrofurantoin is one of the well known reasons to cause acute renal impairment.

Is nitrofurantoin also nephrotoxic?

Nitrofurantoin is known to be a cause for acute renal impairment. It is also not recommended to patients who have renal dysfunction with glomerular filtration rate below 60 ml per minute 1.73 metre square as it leaves toxic formation and could result in pulmonary toxicity ,hepatotoxicity and hemolytic anemia as well.

The other  nephrotoxic drugs include vancomycin and colistin. According to the research conducted, 56% of the patients had a negative experience with nitrofurantoin.

Which antibiotics are generally contraindicated in CKD?

Many antibiotics are contraindicated or need regulation in CKD. Some of them include phase prophylactic psychotropic drugs when GFR drops to below 60ml/min , anti diabetic drugs, antibiotics such as cefepime  should be avoided. The other  medicines that need to be adjusted include pain medicines, nonsteroidal anti-inflammatory drugs such as ibuprofen and naproxen.

Some of the nephrotoxic antibiotics include neomycin, kanamycin, paromomycin , bacitracin, the polymyxins and amphotericin b.

Can nitrofurantoin penetrate the kidneys?

Nitrofurantoin is an antibiotic that kills the bacteria causing urinary tract infections.. It is effective in the treatment of bladder infections but it is less known to penetrate the kidney tissues so it is not recommended for pyelonephritis or perinephric abscesses. However the nitrofurantoin drug is well absorbed in the  gastrointestinal tract where most of the absorption takes place in the proximal small bowel and is screwed out through bile and urine in large amounts from the body. This drug should be avoided for long term as it causes some irreversible complications further.

Who is not recommended to take nitrofurantoin?

Nitrofurantoin antibiotic is usually used for the treatment of urinary tract infections and always remains the first line treatment option for UTI but it is not recommended for every person in such cases. A proper regulation must be done before taking this medicine based on certain factors such as the stage of a disease and other factors linked with this disease . Here are some cases where patients should limit or stop taking Nitrofurantoin or it may generate some serious ill effects:- 

  • Patients with allergic reactions should avoid Nitrofurantoin .
  • Severe kidney disease patients with glomerular filtration rate below 50 ml/min/1.73m2 , need to strictly avoid using this medicine.
  • If a patient has a history of jaundice or liver diseases, then he/she needs consultation from the specialist first. 
  • A pregnant woman into the last 2to 4 weeks of gestation period should avoid taking this Nitrofurantoin drug . 
  • Elderly patients who are more likely to have age related disorders such as heart, liver, lung or kidney problems need to limit taking of Nitrofurantoin and require proper caution receiving this drug. 

Why is Nitrofurantoin regarded as  the first line for UTI? 

Nitrofurantoin always remains the first line for UTI because it is associated with lower chances of antibiotic resistance and has few adverse effects as compared to the other classes of antibiotics. So, it remains the first choice agent for such infections.

What are the best antibiotics for kidney infections?

The commonly best used antibiotics for kidney infections includes Ciprofloxacin, cefalexin , co- amoxiclav or trimethoprim, fosfomycin, bactrim , Cipro, clindamycin, Amoxicillin, doxycycline.

What are the best antibiotics for uncomplicated UTI?

The drugs that are commonly used for uncomplicated UTI ‘s includes trimethoprim/ sulfamethoxazole, Fosfomycin, , Nitrofurantoin (macrodantin, macrobid ) , cephalexin ,ceftriaxone , beta- lactams , fluoroquinolones , fosfomycin tromethamine. 

What are the best antibiotics for UTI in elderly patients?

The elderly patients need to take proper care and caution before regulating any antibiotic for dosing as some might be related to toxicity in the bodies that may cause other uncomplicated diseases. However, for UTI in elderly patients, Ciprofloxacin and Levofloxacin are the most commonly prescribed fluoroquinolones for UTI. Amoxicillin is also the first line treatment option for older patients . Other narrow spectrum antibiotics should be used when patients are having some chronic kidney disorder. 

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