Nitrofurantoin

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Nitrofurantoin
Structural formula of nitrofurantoin
Ball-and-stick model of the nitrofurantoin molecule
Clinical data
Trade namesMacrobid, Macrodantin, Macpac, others[1]
AHFS/Drugs.comMonograph
MedlinePlusa682291
License data
Pregnancy
category
  • AU: A
Routes of
administration		By mouth
ATC code
Legal status
Legal status
Pharmacokinetic data
Bioavailability40%
MetabolismLiver (75%)
Elimination half-life20 minutes
ExcretionKidney and bile duct
Identifiers
  • (E)-1-[(5-nitro-2-furyl)methylideneamino]imidazolidine-2,4-dione
JSmol)
Melting point270 to 272 °C (518 to 522 °F) (decomp.)
  • O=[N+]([O-])c2oc(/C=N/N1C(=O)NC(=O)C1)cc2
  • InChI=1S/C8H6N4O5/c13-6-4-11(8(14)10-6)9-3-5-1-2-7(17-5)12(15)16/h1-3H,4H2,(H,10,13,14)/b9-3+ checkY
  • Key:NXFQHRVNIOXGAQ-YCRREMRBSA-N checkY
 ☒NcheckY (what is this?)  (verify)

Nitrofurantoin is an

antibacterial medication of the nitrofuran class used to treat urinary tract infections, although it is not as effective for kidney infections.[2] It is taken by mouth.[2]

Common side effects include nausea, loss of appetite, diarrhea, and headaches.[2] Rarely numbness, lung problems, or liver problems may occur.[2] It should not be used in people with kidney problems.[2] While it appears to be generally safe during pregnancy it should not be used near delivery.[2][3] While it usually works by slowing bacterial growth, it may result in bacterial death at the high concentrations found in urine.[2]

Nitrofurantoin was first sold in 1953.

generic medication.[2] In 2021, it was the 135th most commonly prescribed medication in the United States, with more than 4 million prescriptions.[6][7]

Medical uses

100 mg Macrobid, Canada

Uses include the treatment of uncomplicated urinary tract infections (UTIs) and prophylaxis against UTIs in people prone to recurrent UTIs.[8]

Increasing bacterial

fluoroquinolones, has led to increased interest in using nitrofurantoin.[9][10] The efficacy of nitrofurantoin in treating UTIs combined with a low rate of bacterial resistance to this agent makes it one of the first-line agents for treating uncomplicated UTIs as recommended by the Infectious Diseases Society of America and the European Society for Microbiology and Infectious Diseases.[11]

Nitrofurantoin is not recommended for the treatment of pyelonephritis,[11] and intra-abdominal abscess,[12] because of extremely poor tissue penetration and low blood levels.

Antibacterial activity

Nitrofurantoin has been shown to have good activity against:[citation needed]

It is used in the treatment of infections caused by these organisms.[13]

Many or all strains of the following genera are resistant to nitrofurantoin:[13]

Special populations

Pregnancy

Nitrofurantoin is pregnancy category A in Australia.[14] It is one of the few drugs commonly used in pregnancy to treat UTIs.[15] It however should not be used in late pregnancy due to the potential risk of hemolytic anemia in the newborn.[14] Newborns of women given this drug late in pregnancy had a higher risk of developing neonatal jaundice.[16]

Evidence of safety in early pregnancy is mixed as of 2017.

meta analysis found no increased risk from first trimester use in cohort studies that was a slight increase of malformations in case control studies.[18]

Available forms

There are two formulations of nitrofurantoin:

  • Macrocrystals (Macrodantin, Furadantin) – 25, 50, or 100 mg capsules – taken once every 6 hours[citation needed][19]
  • Monohydrate/macrocrystals (Macrobid) – 100 mg capsules – taken once every 12 hours or 2 times a day[20] (written on prescriptions as BID, which is the last part of the trade name MacroBID). It is 75% monohydrate and 25% macrocrystals.[21]

Contraindications

Nitrofurantoin is contraindicated in patients with decreased renal function (CrCl < 60 ml/min) due to systemic accumulation and subtherapeutic levels reached in the urinary tract.

AGS Beers Criteria.[23]

Nitrofurantoin is also contraindicated in babies up to the age of one month, as they have immature enzyme systems in their

intravascular hemolysis resulting in anemia.[8]

Adverse effects

The most common side effects with nitrofurantoin are nausea, headache, and flatulence. Less common adverse events (occurring in less than 1% of those taking the drug) include:[8]

  • Gastrointestinal: diarrhea,
    emesis
  • Neurologic: dizziness, drowsiness, amblyopia
  • Respiratory: acute pulmonary hypersensitivity reaction
  • Allergic:
    urticaria
  • Dermatologic: hair loss
  • Miscellaneous: fever, chills, malaise

Lung toxicity

The pulmonary toxicity caused by nitrofurantoin can be categorized into acute, subacute, and chronic pulmonary reactions. The acute and subacute reactions are thought to be due to a hypersensitivity reaction and often resolve when the drug is discontinued. Acute reactions have been estimated to occur in about one in 5000 women who take the drug.

epigastric pain. Chest radiograph will often show unilateral or bilateral infiltrates similar to pulmonary edema. Treatment includes discontinuation of the nitrofurantoin, which should result in symptom improvement within 24 hours.[26]

Chronic pulmonary reactions caused by nitrofurantoin include diffuse

interstitial pneumonitis, pulmonary fibrosis, or both.[8] This uncommon reaction may occur 1 month to 6 years after starting the drug and is usually related to its total lifetime dose.[citation needed] This reaction manifests with progressive shortness of breath.[27] It is important to recognize nitrofurantoin as possible cause of symptoms and discontinue the drug when the suspicion of pulmonary side effects arises as it can be reversible if the drug is stopped early.[25]

Liver toxicity

Hepatic reactions, including hepatitis, cholestatic jaundice, chronic active hepatitis, and hepatic necrosis, occur rarely. The onset of chronic active hepatitis may be insidious, and patients should be monitored periodically for changes in biochemical tests that would indicate liver injury.[8] These reactions usually occur after exposure to the drug for more than 6 weeks. If signs of liver failure are observed in a patient taking nitrofurantoin, the drug should be discontinued. Re-challenge with the drug at a later date is not recommended, as the reaction may have a hypersensitivity component and recur when the drug is resumed.[28]

Neuropathy

Neuropathy is a rare side effect of taking nitrofurantoin. Patients may experience numbness and tingling in a stocking-glove pattern, which may or may not improve upon discontinuation of the drug.[29]

Pharmacology

Organisms are said to be susceptible to nitrofurantoin if their

cystitis
.

At the concentrations achieved in urine (>100 μg/mL), nitrofurantoin is a

bacteriostatic against most susceptible organisms at concentrations less than 32 μg/mL.[8]

Nitrofurantoin and the quinolone antibiotics are mutually antagonistic in vitro. It is not known whether this is of clinical significance, but the combination should be avoided.[8]

Resistance to nitrofurantoin may be chromosomal or plasmid-mediated and involves inhibition of nitrofuran reductase.[32] Acquired resistance in E. coli continues to be rare.

Nitrofurantoin and its metabolites are excreted mainly by the kidneys. In renal impairment, the concentration achieved in urine may be subtherapeutic. Nitrofurantoin should not be used in patients with a

creatinine clearance of 60 mL/min or less. However, a retrospective chart review may suggest nitrofurantoin is not contraindicated in this population.[33]

Mechanism of action

Nitrofurantoin is concentrated in the urine, leading to higher and more effective levels in the urinary tract than in other tissues or compartments.[25] With a 100 mg oral dose, plasma levels are typically less than 1 µg/mL while in the urine it reaches 200 µg/mL.[34]

The drug works by damaging bacterial

pyruvate metabolism and other macromolecules within the cell. Nitrofurantoin exerts greater effects on bacterial cells than mammalian cells because bacterial cells activate the drug more rapidly. It is not known which of the actions of nitrofurantoin is primarily responsible for its bactericidal activity. The broad mechanism of action for this drug likely is responsible for the low development of resistance to its effects, as the drug affects many different processes important to the bacterial cell.[8]

History

Nitrofurantoin has been available for the treatment of lower urinary tract infections (UTIs) since 1953.[4]

Society and culture

Brand names

Nitrofurantoin is marketed under many names in countries worldwide.[36]

Animal feed

Residues from the breakdown of nitrofuran veterinary antibiotics, including nitrofurantoin, have been found in chicken in Vietnam, China, Brazil, and Thailand.[37] The European Union banned the use of nitrofurans in food producing animals by classifying it in ANNEX IV (list of pharmacologically active substances for which no maximum residue limits can be fixed) of the Council Regulation 2377/90. The Food and Drug Administration (FDA) of the United States has prohibited furaltadone since February 1985 and withdrew the approval for the other nitrofuran drugs (except some topical uses) in January 1992. The topical use of furazolidone and nitrofurazone was prohibited in 2002. Australia prohibited the use of nitrofurans in food production in 1992. Japan did not allocate MRLs for nitrofurans leading to the implementation of a "zero tolerance or no residue standard". In Thailand, the Ministry of Health issued in 2001 Proclamation No. 231 MRL of veterinary drug in food which did not allocate MRL for nitrofurans. The Ministry of Agriculture and Cooperatives had already prohibited importation and use of furazolidone and nitrofurazone in animal feed in 1999 which was extended to all nitrofurans in 2002. Several metabolites of nitrofurans, such as furazolidone, furaltadone and nitrofurazone cause cancer or genetic damage in rats.[37]

References

  1. ^ "Nitrofurantoin".
  2. ^ a b c d e f g h "Nitrofurantoin". The American Society of Health-System Pharmacists. Archived from the original on 7 July 2015. Retrieved 1 August 2015.
  3. ^ "Prescribing medicines in pregnancy database". Australian Government. 3 March 2014. Archived from the original on 8 April 2014. Retrieved 22 April 2014.
  4. ^
    ISBN 9780124115255. Archived
    from the original on 8 September 2017.
  5. hdl:10665/325771
    . WHO/MVP/EMP/IAU/2019.06. License: CC BY-NC-SA 3.0 IGO.
  6. ^ "The Top 300 of 2021". ClinCalc. Archived from the original on 15 January 2024. Retrieved 14 January 2024.
  7. ^ "Nitrofurantoin - Drug Usage Statistics". ClinCalc. Retrieved 14 January 2024.
  8. ^ a b c d e f g h i j "Macrobid Drug Label" (PDF). FDA. Archived (PDF) from the original on 21 April 2014. Retrieved 21 April 2014.
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  14. ^ a b "Nitrofurantoin Use During Pregnancy". Drugs.com. Archived from the original on 3 December 2018. Retrieved 10 September 2019.
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  17. ^ a b c "Sulfonamides, Nitrofurantoin, and Risk of Birth Defects - ACOG". www.acog.org. Archived from the original on 30 September 2019. Retrieved 25 November 2019.
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  19. ^ USFDA datahttps://www.accessdata.fda.gov/drugsatfda_docs/label/2013/016620s072lbl.pdf
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  21. ^ "Nitrofurantoin Capsules - FDA prescribing information, side effects and uses". Drugs.com. Archived from the original on 1 December 2017. Retrieved 28 November 2017.
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  36. ^ "Nitrofurantoin". drugs.com. Archived from the original on 18 May 2015. Retrieved 2 May 2015.
  37. ^ a b "Joint FAO/WHO Technical Workshop on Residues of Veterinary Drugs without ADI/MRL - Bangkok, 24 – 26 August 2004". www.fao.org. Archived from the original on 4 December 2008.
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