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Furadantin Side Effects

Generic Name: nitrofurantoin

Note: This page contains information about the side effects of nitrofurantoin. Some of the dosage forms included on this document may not apply to the brand name Furadantin.

For the Consumer

Applies to nitrofurantoin: oral capsule, oral suspension, oral tablet

In addition to its needed effects, some unwanted effects may be caused by nitrofurantoin (the active ingredient contained in Furadantin). In the event that any of these side effects do occur, they may require medical attention.

Major Side Effects

You should check with your doctor immediately if any of these side effects occur when taking nitrofurantoin:

More common:
  • Changes in facial skin color
  • chest pain
  • chills
  • cough
  • fever
  • general feeling of discomfort or illness
  • hives
  • hoarseness
  • itching
  • joint or muscle pain
  • shortness of breath
  • skin rash
  • sudden trouble in swallowing or breathing
  • swelling of the face, mouth, hands, or feet
  • troubled breathing
Less common:
  • Black, tarry stools
  • blood in the urine or stools
  • burning, numbness, tingling, or painful sensations
  • dizziness
  • drowsiness
  • headache
  • pinpoint red spots on the skin
  • sore throat
  • unsteadiness or awkwardness
  • unusual bleeding or bruising
  • unusual tiredness or weakness
  • weakness in the arms, hands, legs, or feet
  • Abdominal or stomach pain
  • blindness
  • blistering, peeling, or loosening of the skin and mucous membranes
  • blue-yellow color blindness
  • bluish color of the fingernails, lips, skin, palms, or nail beds
  • blurred vision or loss of vision, with or without eye pain
  • bulging soft spot on the head of an infant
  • change in the ability to see colors, especially blue or yellow
  • confusion
  • cracks in the skin
  • darkening of the urine
  • decreased vision
  • diarrhea
  • diarrhea, watery and severe, which may also be bloody
  • eye pain
  • general tiredness and weakness
  • light-colored stools
  • loss of appetite
  • loss of heat from the body
  • mental depression
  • mood or mental changes
  • nausea or vomiting
  • pale skin
  • pale stools
  • red skin lesions, often with a purple center
  • red, irritated eyes
  • red, swollen skin
  • red, thickened, or scaly skin
  • skin rash
  • sores, ulcers, or white spots on the lips or in the mouth
  • swollen or painful glands
  • tenderness of salivary glands
  • unpleasant breath odor
  • upper right abdominal pain
  • visual changes
  • vomiting of blood
  • wheezing or tightness in the chest
  • yellow eyes or skin

Minor Side Effects

Some of the side effects that can occur with nitrofurantoin may not need medical attention. As your body adjusts to the medicine during treatment these side effects may go away. Your health care professional may also be able to tell you about ways to reduce or prevent some of these side effects. If any of the following side effects continue, are bothersome or if you have any questions about them, check with your health care professional:

More common:
  • Diarrhea
  • gas
Incidence not known:
  • Dizziness or lightheadedness
  • feeling of constant movement of self or surroundings
  • lack or loss of strength
  • loss of hair, temporary
  • sensation of spinning
  • uncontrolled eye movements

For Healthcare Professionals

Applies to nitrofurantoin: compounding powder, oral capsule, oral suspension


Nausea, emesis, and anorexia occurred most often; abdominal pain and diarrhea were less common. These side effects were dose-related (minimized by dose reduction) and occurred more frequently with Furadantin(R), the crystalline form of the drug. Administration of the drug with food reduced gastrointestinal intolerance.

Comparative studies of the gastrointestinal side effects of the crystalline form (Furadantin[R]) and the macrocrystalline form (Macrodantin[R]) reported up to 34% gastrointestinal intolerance with the crystalline form and up to 13% with the macrocrystalline form. In patients who were unable to tolerate Furadantin(R), 80% were able to tolerate Macrodantin(R).

The onset of pseudomembranous colitis symptoms has been reported during and after antimicrobial therapy.

Pancreatitis due to nitrofurantoin (the active ingredient contained in Furadantin) has been reported. In one case, the patient experienced cholestatic jaundice secondary to edema of the pancreas.[Ref]

Common (1% to 10%): Nausea (8%), flatulence (1.5%)
Uncommon (0.1% to 1%): Diarrhea (less than 1%), dyspepsia (less than 1%), abdominal pain (less than 1%), constipation (less than 1%), emesis (less than 1%)
Rare (less than 0.1%): Parotitis, pseudomembranous colitis
Frequency not reported: Anorexia, sialadenitis, pancreatitis[Ref]


Uncommon (0.1% to 1%): Acute pulmonary hypersensitivity reaction (less than 1%)
Rare (less than 0.1%): Cyanosis
Frequency not reported: Pulmonary hypersensitivity reactions (chronic and subacute), chronic pulmonary reactions (symptoms include malaise, exertional dyspnea, cough, altered pulmonary function, radiologic/histologic findings of diffuse interstitial pneumonitis and/or fibrosis), acute pulmonary reactions (symptoms include fever, chills, cough, chest pain, dyspnea, pulmonary infiltration with consolidation or pleural effusion on x-ray, eosinophilia), pulmonary toxicity (acute and chronic), alveolar infiltrates, alveolar hemorrhage (including fatal cases), interstitial fibrosis, pneumonitis, drug-induced bronchiolitis obliterans with organizing pneumonia[Ref]

Respiratory system side effects have included both acute and chronic pulmonary toxicity. Acute toxicity has occurred from within a few hours to 3 weeks after therapy was started and consisted of dyspnea, cough, fever, and chills. Chronic toxicity has generally occurred after 6 months of therapy and has presented with an insidious onset of dyspnea, cough, malaise, and fatigue.

Respiratory side effects associated with nitrofurantoin therapy have occurred as both acute and chronic events. Acute pulmonary reactions have manifested as a type of hypersensitivity, and have occurred rapidly in patients who were previously sensitized. Of one group of 447 pulmonary reactions reported, 89% were of the acute type. Patients commonly had eosinophilia. Lung changes generally included alveolar infiltrates. Alveolar hemorrhage and death have been reported. Symptoms generally resolved within 24 to 48 hours after nitrofurantoin was discontinued.

Chronic pulmonary reactions occurred after 6 months of therapy and were generally more severe. Biopsy often revealed interstitial fibrosis. Eosinophilia was less common. Positive antinuclear antibodies were reported in up to 66% of patients, and patients commonly exhibited abnormal liver function tests. Resolution of symptoms usually occurred over a few months, although deaths have been reported. It has been suggested that the mechanism of this reaction is a combination of drug toxicity and an immune reaction.[Ref]


Frequency not reported: Changes in EKG (e.g., nonspecific ST/T wave changes, bundle branch block) associated with pulmonary reactions


Rare (less than 0.1%): Hepatic reactions (including hepatitis, cholestatic jaundice, chronic active hepatitis, hepatic necrosis), hepatotoxicity with concurrent pulmonary reactions
Frequency not reported: Elevated AST (SGOT), elevated ALT (SGPT), elevated bilirubin, hepatic toxicity (presented with jaundice, abdominal pain, malaise, nausea, and anorexia)[Ref]

Fatalities have been reported with hepatic reactions.

Hepatic toxicity has occurred more often following lengthy therapy (6 months or more) and has presented with jaundice, abdominal pain, malaise, nausea, and anorexia.

Most acute hepatic reactions were self-limiting and resolved within a few days. Patients who experienced chronic reactions often had positive antinuclear antibodies (77%) and may have developed chronic active hepatitis or hepatic necrosis. Liver function tests generally returned to normal after a few months, although deaths due to hepatic failure have been reported.

Hepatotoxicity with concurrent pulmonary effects following the use of nitrofurantoin has been reported and may be mediated by the immune system. A case of hepatotoxicity accompanied by elevations in serum immune globulins (IgG) has been reported. The authors theorized that cytotoxic T cells (CD8) were involved in the liver damage. They postulated that the antigen-antibody complex was removed when the drug was discontinued as evidenced by the patient's rapidly corrected liver enzyme levels.[Ref]

Nervous system

Common (1% to 10%): Headache (6%)
Uncommon (0.1% to 1%): Dizziness (less than 1%), drowsiness (less than 1%)
Rare (less than 0.1%):Vertigo, benign intracranial hypertension (pseudotumor cerebri), bulging fontanels
Frequency not reported: Peripheral neuropathy, vertigo, neuropathy (generally beginning as paresthesia of the lower extremities and the hands and progressing to muscle weakness and wasting), cerebellar dysfunction[Ref]

Peripheral neuropathy (which may become severe or irreversible) has occurred; fatalities have been reported. Risk of peripheral neuropathy may be increased with renal impairment (CrCl less than 60 mL/min or clinically significant elevated serum creatinine), anemia, vitamin B deficiency, diabetes mellitus, electrolyte imbalance, and/or debilitating disease.

Peripheral neuropathy has developed after a few days to several months of therapy. There was no consistent relationship between the dose, length of therapy, and neuropathy development. In a review of 100 cases of peripheral neuropathy, 34 experienced total regression, 45 had partial regression, 13 had no change, and 8 died.[Ref]


Rare (less than 0.1%): Cyanosis secondary to methemoglobinemia, aplastic anemia
Frequency not reported: Hemolytic anemia, leukopenia, agranulocytosis, granulocytopenia, megaloblastic anemia, eosinophilia, decreased hemoglobin, glucose-6-phosphate dehydrogenase deficiency anemia, thrombocytopenia[Ref]


Uncommon (0.1% to 1%): Pruritus (less than 1%), urticaria (less than 1%)
Frequency not reported: Lupus-like syndrome associated with pulmonary reactions, angioedema, eruptions (maculopapular, erythematous, and eczematous), anaphylaxis, arthralgia, myalgia, drug fever, chills, vasculitis (sometimes associated with pulmonary reactions)
Postmarketing reports: Hypersensitivity reactions[Ref]

Hypersensitivity reactions were the most frequently reported side effect during postmarketing experience.[Ref]


Uncommon (0.1% to 1%): Alopecia (less than 1%)
Rare (less than 0.1%): Exfoliative dermatitis, erythema multiforme (including Stevens-Johnson syndrome)
Frequency not reported: Transient alopecia


Uncommon (0.1% to 1%): Amblyopia (less than 1%)
Rare (less than 0.1%): Retinopathy due to intraretinal crystals (at least 1 case)
Frequency not reported: Diplopia, nystagmus
Postmarketing reports: Optic neuritis (rare)[Ref]

Retinopathy due to intraretinal crystals has been reported in a patient with a 9-year history of nitrofurantoin use.[Ref]


Uncommon (0.1% to 1%): Fever (less than 1%), chills (less than 1%), malaise (less than 1%)
Rare (less than 0.1%): Systemic lupus erythematous-like reactions
Frequency not reported: Asthenia, superinfections due to resistant organisms[Ref]


Rare (less than 0.1%): Acute interstitial nephritis[Ref]


Rare (less than 0.1%): Confusion, depression, psychotic reactions


Frequency not reported: Increased serum phosphorus, increased alkaline phosphatase, increased lactate dehydrogenase, increased creatine phosphokinase[Ref]


Frequency not reported: Dark discoloration of urine[Ref]


1. Hailey FJ, Gascock HW "Gastrointestinal tolerance to a new macrocrystalline form of nitrofurantoin: a collaborative study." Curr Ther Res Clin Exp 9 (1967): 600-5

2. Kalowski S, Radford N, Kincaid-Smith P "Crystalline and macrocyrstalline nitrofurantoin in the treatment of urinary-tract infection." N Engl J Med 290 (1974): 385-97

3. Christophe JL "Pancreatitis induced by nitrofurantoin." Gut 35 (1994): 712-3

4. Kammire LD, Donofrio PD "Nitrofurantoin neuropathy: a forgotten adverse effect." Obstet Gynecol 110 (2007): 510-2

5. Nelis GF "Nitrofurantoin-induced pancreatitis: report of a case." Gastroenterology 84 (1983): 1032-4

6. Averbuch SD, Yungbluth P "Fatal pulmonary hemorrhage due to nitrofurantoin." Arch Intern Med 140 (1980): 271-3

7. Jick SS, Jick H, Walker AM, Hunter JR "Hospitalizations for pumonary reactions following nitrofurantoin use." Chest 96 (1989): 512-5

8. Beigel R, Perets R, Mouallem M "Acute Kidney Injury, Hepatitis, and CPK Elevation Associated With Nitrofurantoin Therapy." Am J Med Sci 337 (2009): 132-3

9. Reinhart HH, Reinhart E, Korlipara P, Peleman R "Combined nitrofurantoin toxicity to liver and lung." Gastroenterology 102 (1992): 1396-9

10. Schatz M, Wasserman S, Patterson R "Eosinophils and immunologic lung disease." Med Clin North Am 65 (1981): 1055-71

11. Robinson BW "Nitrofurantoin-induced interstitial pulmonary fibrosis." Med J Aust 1 (1983): 72-6

12. Israel RH, Gross RA, Bomba PA "Adult respiratory distress syndrome associated with acute nitrofurantoin toxicity." Respiration 39 (1980): 318-22

13. Willcox PA, Maze SS, Sandler M, Benatar SR "Pulmonary fibrosis following long-term nitrofurantoin therapy." S Afr Med J 61 (1982): 714-7

14. Brutinel WM, Martin WJ "Chronic nitrofurantoin reaction associated with t-lymphocyte alveolitis." Chest 89 (1986): 150-2

15. Jayasundera NS, Johnson RD, Nicholson MP "Chronic pulmonary reaction to nitrofurantoin." JAMA 243 (1980): 769

16. Robinson GM, Bai TR, Steele RH "Nitrofurantoin induced chronic pulmonary reaction: case report." N Z Med J 91 (1980): 50-2

17. Magee F, Wright JL, Chan N, et al "Two unusual pathological reaction to nitrofurantoin: case reports." Histopathology 10 (1986): 701-6

18. Bryant DH "Drug-induced plumonary disease." Med J Aust 156 (1992): 802-5

19. Bucknall CE, Adamson MR, Banham SW "Non fatal pulmonary haemorrhage associated with nitrofurantoin." Thorax 42 (1987): 475-6

20. Hainer BL, White AA "Nitrofurantoin pulmonary toxicity." J Fam Pract 13 (1981): 817-23

21. Robinson C, Nyi PP "Probable nitrofurantoin-induced bronchiolitis obliterans with organizing pneumonia." Am J Health Syst Pharm 66 (2009): 1919-22

22. Schattner A, VonderWalde J, Kozak N, Sokolovskaya N, Knobler H "Nitrofurantoin-induced immune-mediated lung and liver disease." Am J Med Sci 317 (1999): 336-40

23. Homberg L, Boman G "Pulmonary reactions to nitrofurantoin." Eur J Respir Dis 62 (1981): 186-9

24. Witten CM "Pulmonary toxicity of nitrofurantoin." Arch Phys Med Rehabil 70 (1989): 55-7

25. Podevin P, Biour M "Drug-induced ''allergic hepatitis''." Clin Rev Allergy Immunol 13 (1995): 223-44

26. Burgert SJ, Burke JP, Box TD "Reversible nitrofurantoin-induced chronic active hepatitis and hepatic cirrhosis in a patient awaiting liver transplantation." Transplantation 59 (1995): 448-9

27. Kelly BD, Heneghan MA, Connolly CE, OGorman TA "Nitrofurantoin-induced hepatotoxicity mediated by CD8+ T cells." Am J Gastroenterol 93 (1998): 819-21

28. Maskell R "Nitrofurantoin induced chronic liver disease." J Antimicrob Chemother 19 (1987): 140

29. Miller AR, Addis BJ, Clarke PD "Nitrofurantoin and chronic active hepatitis." Ann Intern Med 97 (1982): 452

30. Thuluvath PJ, McKendrick MW "Nitrofurantoin induced chronic liver disease." J Antimicrob Chemother 18 (1986): 291-2

31. Mulberg AE, Bell LM "Fatal cholestatic hepatitis and multisystem failure associated with nitrofurantoin." J Pediatr Gastroenterol Nutr 17 (1993): 307-9

32. Mollison LC, Angus P, Richards M, Jones RM, Ireton J "Hepatitis due to nitrofurantoin." Med J Aust 156 (1992): 347-9

33. Sharp JR, Ishak KG, Zimmerman HJ "Chronic active hepatitis and sever heptic necrosis associated with nitrofurantoin." Ann Intern Med 92 (1980): 14-9

34. Black M, Rabin L, Schatz N "Nitrofurantoin-induced chronic active hepatitis." Ann Intern Med 92 (1980): 62-4

35. Sippel PJ, Agger WA "Nitrofurantoin-induced granulomatous hepatitis." Urology 18 (1981): 177-8

36. Stricker BH, Blok AP, Claas FH, Van Parys GE, Des Met VJ "Hepatic injury associated with the use of nitrofurans: a clinicopathological study of 52 reported cases." Hepatology 8 (1988): 599-608

37. Korzets A, Rathaus M, Chen B, Bernheim J "Pseudotumor cerebri and nitrofurantoin." Drug Intell Clin Pharm 22 (1988): 345

38. White WT, Harrison L, Dumas J "Nitrofurantoin unmasking peripheral neuropathy in a type 2 diabetic patient." Arch Intern Med 144 (1984): 821

39. Spring PJ, Sharpe DM, Hayes MW "Nitrofurantoin and peripheral neuropath: a forgotten problem?." Medical Journal of Australia 174 (2001): 153-4

40. Craven RS "Furadantin neuropathy." Aust N Z J Med 3 (1971): 246-9

41. Yiannikas C, Pollard JD, McLeod JG "Nitrofurantoin neuropathy." Aust N Z J Med 11 (1981): 400-5

42. "Product Information. Macrobid (nitrofurantoin)." Procter and Gamble Pharmaceuticals, Cincinnati, OH.

43. Roberts AD, Neelamegam M "Agranulocytosis associated with nitrofurantoin therapy." Ann Pharmacother 39 (2004): 198

44. "Product Information. Macrodantin (nitrofurantoin)." Procter and Gamble Pharmaceuticals, Cincinnati, OH.

45. Carroll DA "Nitrofurantoin induced neutropenia: case report." Mil Med 149 (1984): 570-1

46. Pellinen TJ, Kalske J "Nitrofurantoin-induced parotitis." Br Med J (Clin Res Ed) 285 (1982): 344

47. Meyboom RH, Van Gent A, Zinkstok DJ "Nitrofurantoin-induced parotitis." Br Med J (Clin Res Ed) 285 (1982): 1049

48. Sanford RG, Olmstead PM "Nitrofurantoin-induced antinuclear antibodies and panniculitis." Arthritis Rheum 30 (1987): 1076-8

49. Young EJ, Fainstein V, Musher DM "Drug-induced fever: cases seen in the evaluation of unexplained fever in a general hospital population." Rev Infect Dis 4 (1982): 69-77

50. Adkinson NF "Drug allergy." JAMA 268 (1992): 771-3

51. Chapman JA "An unusual nitrofurantoin-induced drug reaction." Ann Allergy 56 (1986): 16-8

52. Ibanez HE, Williams DF, Boniuk I "Crystalline retinopathy associated with long-term nitrofurantoin therapy." Arch Ophthalmol 112 (1994): 304-5

53. Dyer IE, Sankary TM, Dawson JA "Antibiotic resistance in bacterial urinary tract infections, 1991 to 1997." West J Med 169 (1998): 265-8

54. Kahn SR "Acute interstitial nephritis associated with nitrofurantoin." Lancet 348 (1996): 1177-8

Not all side effects for Furadantin may be reported. You should always consult a doctor or healthcare professional for medical advice. Side effects can be reported to the FDA here.

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