Macrobid Side Effects

Generic name: nitrofurantoin

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

Some side effects of Macrobid may not be reported. Always consult your doctor or healthcare specialist for medical advice. You may also report side effects to the FDA.

For the Consumer

Applies to nitrofurantoin: oral capsule, oral suspension

Get emergency medical help if you have any of these signs of an allergic reaction while taking nitrofurantoin (the active ingredient contained in Macrobid) hives; difficulty breathing; swelling of your face, lips, tongue, or throat.

Stop using nitrofurantoin and call your doctor at once if you have a serious side effect such as:

• diarrhea that is watery or bloody;

• shortness of breath, running out of breath easily;

• sudden chest pain or discomfort, wheezing, dry cough or hack;

• fever, chills, body aches, unexplained weight loss;

• peripheral neuropathy - numbness, tingling, or pain in your hands or feet;

• nausea, upper stomach pain, itching, loss of appetite, dark urine, clay-colored stools, jaundice (yellowing of the skin or eyes);

• pale skin, easy bruising, confusion or weakness;

• patchy skin color, red spots, or a severe blistering, peeling, and red skin rash; or

• severe headache, ringing in your ears, dizziness, vision problems, pain behind your eyes.

Less serious side effects of nitrofurantoin may include:

• upset stomach, vomiting;

• mild diarrhea;

• rust-colored or brownish urine; or

• vaginal itching or discharge.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects.

For Healthcare Professionals

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

Gastrointestinal

Gastrointestinal side effects have included nausea, vomiting, anorexia, diarrhea, and abdominal pain. These adverse effects occur more frequently with Furadantin (R), the crystalline form of the drug. Administration of the drug with food reduces gastrointestinal intolerance. Sialadenitis, pancreatitis, parotitis (rare), and pseudomembranous colitis have also been reported.

Comparative studies of the gastrointestinal adverse 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).

Pancreatitis due to nitrofurantoin has been reported. In one case the patient experienced cholestatic jaundice secondary to edema of the pancreas.

Respiratory

Respiratory side effects associated with nitrofurantoin (the active ingredient contained in Macrobid) 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 will commonly have eosinophilia. Lung changes generally include alveolar infiltrates. Alveolar hemorrhage and death have been reported. Symptoms generally resolved within 24 to 48 hours after nitrofurantoin is discontinued.

Chronic pulmonary reactions occur after six months of therapy and are generally more severe. Biopsy often reveals interstitial fibrosis. Eosinophilia is less common. Positive antinuclear antibodies are reported in up to 66% of patients, and patients commonly exhibit abnormal liver function tests. Resolution of symptoms usually occurs 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.

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. Cyanosis (rare), alveolar infiltrates, alveolar hemorrhage (including fatal cases), interstitial fibrosis, and pneumonitis have been reported. Nitrofurantoin-induced bronchiolitis obliterans with organizing pneumonia has been reported.

Cardiovascular

Cardiovascular side effects have included changes in EKG (such as nonspecific ST/T wave changes or bundle branch block) associated with pulmonary reactions.

Hepatic

Most acute hepatic reactions are self-limiting and resolve within a few days. Patients who experience chronic reactions often have positive antinuclear antibodies (77%) and may develop chronic active hepatitis or hepatic necrosis. Liver function tests generally return 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 (the active ingredient contained in Macrobid) 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.

Hepatic side effects have included elevated transaminase levels, hepatitis (including fatal cases), elevated bilirubin, cholestatic jaundice, and hepatic necrosis. Hepatotoxicity with concurrent pulmonary reactions has occurred rarely. Hepatic toxicity has occurred more often following lengthy therapy (6 months or more) and has presented with jaundice, abdominal pain, malaise, nausea, and anorexia.

Nervous system

Peripheral neuropathy may develop after a few days to several months of therapy. There is 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. Nitrofurantoin (the active ingredient contained in Macrobid) therapy in those at risk is not recommended.

Nervous system side effects have included headache and dizziness. Less frequently, severe and debilitating peripheral neuropathy due to nitrofurantoin may occur. Neuropathy generally begins as paresthesia of the lower extremities and the hands and progresses to muscle weakness and wasting. Patients at risk include the elderly and those with renal impairment, anemia, vitamin B12 deficiency, diabetes, or debilitating diseases. Vertigo, cerebellar dysfunction, benign intracranial hypertension (pseudotumor cerebri), and confusion have been reported rarely.

Hematologic

Hematologic side effects have included hemolytic anemia, leukopenia, agranulocytosis, granulocytopenia, megaloblastic anemia, cyanosis secondary to methemoglobinemia, eosinophilia, decreased hemoglobin, glucose-6-phosphate dehydrogenase deficiency anemia, thrombocytopenia, and aplastic anemia.

Hypersensitivity

Hypersensitivity side effects have included lupus-like syndrome, angioedema, eruptions (maculopapular, erythematous, and eczematous), anaphylaxis, arthralgia, myalgia, drug fever, and chills.

Dermatologic

Dermatologic side effects have included exfoliative dermatitis, erythema multiforme, and Stevens-Johnson syndrome.

Ocular

Ocular side effects have included amblyopia, diplopia, nystagmus, and optic neuritis. Retinopathy due to intraretinal crystals has been reported in a patient with a nine year history of nitrofurantoin (the active ingredient contained in Macrobid) use.

Other

Other side effects have included systemic lupus erythematous-like reactions (rare), asthenia, fever, chills, and superinfections due to resistant organisms.

Renal

Renal side effects have rarely included acute interstitial nephritis.

Psychiatric

Psychiatric side effects have rarely included depression and psychotic reactions.

Metabolic

Metabolic side effects have included increased serum phosphorus, alkaline phosphatase, lactate dehydrogenase, and creatine phosphokinase.

Genitourinary

Genitourinary side effects have included dark discoloration of urine.

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