Label: NITROFURANTOIN (MONOHYDRATE/MACROCRYSTALS)- nitrofurantoin monohydrate/macrocrystals capsule

To reduce the development of drug-resistant bacteria and maintain the effectiveness of Nitrofurantoin capsules, USP (monohydrate/macrocrystals) and other antibacterial drugs, Nitrofurantoin capsules, USP (monohydrate/macrocrystals) should be used only to treat or prevent infections that are proven or strongly suspected to be caused by bacteria.

Nitrofurantoin, USP is an antibacterial agent specific for urinary tract infections. Nitrofurantoin capsules, USP (monohydrate/macrocrystals) are a hard gelatin capsule shell containing the equivalent of 100 mg of nitrofurantoin, USP in the form of 25 mg of nitrofurantoin macrocrystals and 75 mg of nitrofurantoin monohydrate.

The chemical name of nitrofurantoin macrocrystals is 1-[[[5-nitro-2-furanyl]methylene]amino]-2,4-imidazolidinedione. The chemical structure is the following:

The chemical name of nitrofurantoin monohydrate is 1-[[[5-nitro-2-furanyl]methylene]amino]-2,4- imidazolidinedione monohydrate. The chemical structure is the following:

Inactive Ingredients: Each capsule contains carbomer 934P, carboxymethylcellulose, corn starch, D&C Yellow No. 10, FD&C Red No. 40, gelatin, iron oxide black, iron oxide yellow, lactose, magnesium stearate, maltodextrin, povidone, sodium lauryl sulfate, sugar, talc and titanium dioxide. The black monogramming ink contains butyl alcohol, dehydrated alcohol, iron oxide black, isopropyl alcohol, potassium hydroxide, propylene glycol, purified water, shellac and strong ammonia solution. The white monogramming ink contains butyl alcohol, dehydrated alcohol, isopropyl alcohol, povidone, propylene glycol, shellac, sodium hydroxide and titanium dioxide.

Meets USP Dissolution Test 7.

Each nitrofurantoin capsule (monohydrate/macrocrystals) contains two forms of nitrofurantoin. Twenty-five percent is macrocrystalline nitrofurantoin, which has slower dissolution and absorption than nitrofurantoin monohydrate. The remaining 75% is nitrofurantoin monohydrate contained in a powder blend which, upon exposure to gastric and intestinal fluids, forms a gel matrix that releases nitrofurantoin over time. Based on urinary pharmacokinetic data, the extent and rate of urinary excretion of nitrofurantoin from the 100 mg nitrofurantoin capsule (monohydrate/macrocrystals) are similar to those of 50 mg or 100 mg nitrofurantoin macrocrystals capsule. Approximately 20% to 25% of a single dose of nitrofurantoin is recovered from the urine unchanged over 24 hours.

Plasma nitrofurantoin concentrations after a single oral dose of the 100 mg nitrofurantoin capsule (monohydrate/macrocrystals) are low, with peak levels usually less than 1 mcg/mL. Nitrofurantoin is highly soluble in urine, to which it may impart a brown color. When nitrofurantoin is administered with food, the bioavailability of nitrofurantoin is increased by approximately 40%.

Nitrofurantoin is a nitrofuran antimicrobial agent with activity against certain Gram-positive and Gram-negative bacteria.

Mechanism of Action
The mechanism of the antimicrobial action of nitrofurantoin is unusual among antibacterials. Nitrofurantoin is reduced by bacterial flavoproteins to reactive intermediates which inactivate or alter bacterial ribosomal proteins and other macromolecules. As a result of such inactivations, the vital biochemical processes of protein synthesis, aerobic energy metabolism, DNA synthesis, RNA synthesis and cell wall synthesis are inhibited. Nitrofurantoin is bactericidal in urine at therapeutic doses. The broad-based nature of this mode of action may explain the lack of acquired bacterial resistance to nitrofurantoin, as the necessary multiple and simultaneous mutations of the target macromolecules would likely be lethal to the bacteria.

Interactions with Other Antibiotics
Antagonism has been demonstrated in vitro between nitrofurantoin and quinolone antimicrobials. The clinical significance of this finding is unknown.

Development of Resistance
Development of resistance to nitrofurantoin has not been a significant problem since its introduction in 1953. Cross-resistance with antibiotics and sulfonamides has not been observed, and transferable resistance is, at most, a very rare phenomenon.

Nitrofurantoin has been shown to be active against most strains of the following bacteria both in vitro and in clinical infections (see INDICATIONS AND USAGE).

Aerobic and facultative Gram-positive microorganisms:
Staphylococcus saprophyticus

Aerobic and facultative Gram-negative microorganisms:
Escherichia coli

At least 90 percent of the following microorganisms exhibit an in vitro minimum inhibitory concentration (MIC) less than or equal to the susceptible breakpoint for nitrofurantoin. However, the efficacy of nitrofurantoin in treating clinical infections due to these microorganisms has not been established in adequate and well-controlled trials.

Aerobic and facultative Gram-positive microorganisms:
Coagulase-negative staphylococci (including Staphylococcus epidermidis)
Enterococcus faecalis
Staphylococcus aureus
Streptococcus agalactiae
Group D streptococci
Viridans group streptococci

Aerobic and facultative Gram-negative microorganisms:
Citrobacter amalonaticus
Citrobacter diversus
Citrobacter freundii
Klebsiella oxytoca
Klebsiella ozaenae

Nitrofurantoin is not active against most strains of Proteus species or Serratia species. It has no activity against Pseudomonas species.

Susceptibility Testing:
For specific information regarding susceptibility test interpretive criteria and associated test methods and quality control standards recognized by FDA for this drug, please see: https://www.fda.gov/STIC.

Nitrofurantoin capsules, USP (monohydrate/macrocrystals) are indicated only for the treatment of acute uncomplicated urinary tract infections (acute cystitis) caused by susceptible strains of Escherichia coli or Staphylococcus saprophyticus.

Nitrofurantoin is not indicated for the treatment of pyelonephritis or perinephric abscesses.

To reduce the development of drug-resistant bacteria and maintain the effectiveness of nitrofurantoin capsules, USP (monohydrate/macrocrystals) and other antibacterial drugs, nitrofurantoin capsules, USP (monohydrate/macrocrystals) should be used only to treat or prevent infections that are proven or strongly suspected to be caused by susceptible bacteria. When culture and susceptibility information are available, they should be considered in selecting or modifying antibacterial therapy. In the absence of such data, local epidemiology and susceptibility patterns may contribute to the empiric selection of therapy.

Nitrofurantoins lack the broader tissue distribution of other therapeutic agents approved for urinary tract infections. Consequently, many patients who are treated with nitrofurantoin capsules, USP (monohydrate/macrocrystals) are predisposed to persistence or reappearance of bacteriuria (see CLINICAL STUDIES). Urine specimens for culture and susceptibility testing should be obtained before and after completion of therapy. If persistence or reappearance of bacteriuria occurs after treatment with nitrofurantoin capsules, USP (monohydrate/macrocrystals), other therapeutic agents with broader tissue distribution should be selected. In considering the use of nitrofurantoin capsules, USP (monohydrate/macrocrystals), lower eradication rates should be balanced against the increased potential for systemic toxicity and for the development of antimicrobial resistance when agents with broader tissue distribution are utilized.

Anuria, oliguria, or significant impairment of renal function (creatinine clearance under 60 mL per minute or clinically significant elevated serum creatinine) are contraindications. Treatment of this type of patient carries an increased risk of toxicity because of impaired excretion of the drug.

Because of the possibility of hemolytic anemia due to immature erythrocyte enzyme systems (glutathione instability), the drug is contraindicated in pregnant patients at term (38 to 42 weeks gestation), during labor and delivery, or when the onset of labor is imminent. For the same reason, the drug is contraindicated in neonates under one month of age.

Nitrofurantoin capsules (monohydrate/macrocrystals) are contraindicated in patients with a previous history of cholestatic jaundice/hepatic dysfunction associated with nitrofurantoin.

Nitrofurantoin capsules (monohydrate/macrocrystals) are also contraindicated in those patients with known hypersensitivity to nitrofurantoin.

Pulmonary reactions:
ACUTE, SUBACUTE, OR CHRONIC PULMONARY REACTIONS HAVE BEEN OBSERVED IN PATIENTS TREATED WITH NITROFURANTOIN. IF THESE REACTIONS OCCUR, NITROFURANTOIN SHOULD BE DISCONTINUED AND APPROPRIATE MEASURES TAKEN. REPORTS HAVE CITED PULMONARY REACTIONS AS A CONTRIBUTING CAUSE OF DEATH.

CHRONIC PULMONARY REACTIONS (DIFFUSE INTERSTITIAL PNEUMONITIS OR PULMONARY FIBROSIS, OR BOTH) CAN DEVELOP INSIDIOUSLY. THESE REACTIONS OCCUR RARELY AND GENERALLY IN PATIENTS RECEIVING THERAPY FOR SIX MONTHS OR LONGER. CLOSE MONITORING OF THE PULMONARY CONDITION OF PATIENTS RECEIVING LONG-TERM THERAPY IS WARRANTED AND REQUIRES THAT THE BENEFITS OF THERAPY BE WEIGHED AGAINST POTENTIAL RISKS (SEE RESPIRATORY REACTIONS).

Hepatotoxicity:
Hepatic reactions, including hepatitis, cholestatic jaundice, chronic active hepatitis and hepatic necrosis, occur rarely. Fatalities have been reported. 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. If hepatitis occurs, the drug should be withdrawn immediately and appropriate measures should be taken.

Neuropathy:
Peripheral neuropathy, which may become severe or irreversible, has occurred. Fatalities have been reported. Conditions such as renal impairment (creatinine clearance under 60 mL per minute or clinically significant elevated serum creatinine), anemia, diabetes mellitus, electrolyte imbalance, vitamin B deficiency and debilitating disease may enhance the occurrence of peripheral neuropathy. Patients receiving long-term therapy should be monitored periodically for changes in renal function.

Optic neuritis has been reported rarely in postmarketing experience with nitrofurantoin formulations.

Hemolytic anemia:
Cases of hemolytic anemia of the primaquine-sensitivity type have been induced by nitrofurantoin. Hemolysis appears to be linked to a glucose-6-phosphate dehydrogenase deficiency in the red blood cells of the affected patients. This deficiency is found in 10 percent of Blacks and a small percentage of ethnic groups of Mediterranean and Near-Eastern origin. Hemolysis is an indication for discontinuing nitrofurantoin; hemolysis ceases when the drug is withdrawn.

Clostridium difficile-associated diarrhea:
Clostridium difficile associated diarrhea (CDAD) has been reported with use of nearly all antibacterial agents, including nitrofurantoin, and may range in severity from mild diarrhea to fatal colitis. Treatment with antibacterial agents alters the normal flora of the colon leading to overgrowth of C. difficile.

C. difficile produces toxins A and B which contribute to the development of CDAD. Hypertoxin producing strains of C. difficile cause increased morbidity and mortality, as these infections can be refractory to antimicrobial therapy and may require colectomy. CDAD must be considered in all patients who present with diarrhea following antibiotic use. Careful medical history is necessary since CDAD has been reported to occur over two months after the administration of antibacterial agents.

If CDAD is suspected or confirmed, ongoing antibiotic use not directed against C. difficile may need to be discontinued. Appropriate fluid and electrolyte management, protein supplementation, antibiotic treatment of C. difficile and surgical evaluation should be instituted as clinically indicated.

Information for Patients
Patients should be advised to take nitrofurantoin with food (ideally breakfast and dinner) to further enhance tolerance and improve drug absorption. Patients should be instructed to complete the full course of therapy; however, they should be advised to contact their physician if any unusual symptoms occur during therapy.

Patients should be advised not to use antacid preparations containing magnesium trisilicate while taking nitrofurantoin.

Patients should be counseled that antibacterial drugs including nitrofurantoin should only be used to treat bacterial infections. They do not treat viral infections (e.g., the common cold). When nitrofurantoin is prescribed to treat a bacterial infection, patients should be told that although it is common to feel better early in the course of therapy, the medication should be taken exactly as directed. Skipping doses or not completing the full course of therapy may (1) decrease the effectiveness of the immediate treatment and (2) increase the likelihood that bacteria will develop resistance and will not be treatable by nitrofurantoin or other antibacterial drugs in the future.

Diarrhea is a common problem caused by antibiotics which usually ends when the antibiotic is discontinued. Sometimes after starting treatment with antibiotics, patients can develop watery and bloody stools (with or without stomach cramps and fever) even as late as two or more months after having taken the last dose of the antibiotic. If this occurs, patients should contact their physician as soon as possible.

In clinical trials of nitrofurantoin, the most frequent clinical adverse events that were reported as possibly or probably drug-related were nausea (8%), headache (6%) and flatulence (1.5%). Additional clinical adverse events reported as possibly or probably drug-related occurred in less than 1% of patients studied and are listed below within each body system in order of decreasing frequency:

Gastrointestinal: Diarrhea, dyspepsia, abdominal pain, constipation, emesis

Neurologic: Dizziness, drowsiness, amblyopia

Respiratory: Acute pulmonary hypersensitivity reaction (see WARNINGS)

Allergic: Pruritus, urticaria

Dermatologic: Alopecia

Miscellaneous: Fever, chills, malaise

The following additional clinical adverse events have been reported with the use of nitrofurantoin:

Gastrointestinal: Sialadenitis, pancreatitis. There have been sporadic reports of pseudomembranous colitis with the use of nitrofurantoin. The onset of pseudomembranous colitis symptoms may occur during or after antimicrobial treatment (see WARNINGS).

Neurologic: Peripheral neuropathy, which may become severe or irreversible, has occurred. Fatalities have been reported. Conditions such as renal impairment (creatinine clearance under 60 mL per minute or clinically significant elevated serum creatinine), anemia, diabetes mellitus, electrolyte imbalance, vitamin B deficiency and debilitating diseases may increase the possibility of peripheral neuropathy (see WARNINGS).

Asthenia, vertigo and nystagmus also have been reported with the use of nitrofurantoin.

Benign intracranial hypertension (pseudotumor cerebri), confusion, depression, optic neuritis and psychotic reactions have been reported rarely. Bulging fontanels, as a sign of benign intracranial hypertension in infants, have been reported rarely.

Occasional incidents of acute overdosage of nitrofurantoin have not resulted in any specific symptoms other than vomiting. Induction of emesis is recommended. There is no specific antidote, but a high fluid intake should be maintained to promote urinary excretion of the drug. Nitrofurantoin is dialyzable.

Nitrofurantoin capsules (monohydrate/macrocrystals) should be taken with food.

Adults and Pediatric Patients Over 12 Years: One 100 mg capsule every 12 hours for seven days.

Nitrofurantoin capsules, USP (monohydrate/macrocrystals), 100 mg, are supplied as a gray opaque cap and yellow opaque body imprinted axially “AN” in white ink on the cap and “478” in black ink on the body.
They are available as follows:
Unit dose packages of 50 (5 x 10) NDC 60687-633-65
Unit dose packages of 100 (10 x 10) NDC 60687-633-01

Store at 20° to 25°C (68° to 77°F); excursions permitted between 15° to 30°C (59° to 86°F) [see USP Controlled Room Temperature].

FOR YOUR PROTECTION: Do not use if blister is torn or broken.

Rx Only

Controlled clinical trials comparing nitrofurantoin 100 mg p.o. q12h and nitrofurantoin macrocrystals 50 mg p.o. q6h in the treatment of acute uncomplicated urinary tract infections demonstrated approximately 75% microbiologic eradication of susceptible pathogens in each treatment group.

American Health Packaging unit dose blisters (see How Supplied section) contain drug product from Amneal Pharmaceuticals LLC as follows:
(100 mg / 50 UD) NDC 60687-633-65 packaged from NDC 65162-478
(100 mg / 100 UD) NDC 60687-633-01 packaged from NDC 65162-478

Distributed By:
American Health Packaging
Columbus, OH 43217

8463301/0924F

NDC 60687- 633-65

Nitrofurantoin
Capsules, USP
(monohydrate/macrocrystals)

100 mg

50 Capsules (5 x 10)                 Rx Only

URINARY TRACT ANTIBACTERIAL

Each Capsule Contains:
The equivalent of 100 mg of nitrofurantoin, USP in the form of 25 mg of
nitrofurantoin macrocrystals and 75 mg of nitrofurantoin monohydrate.

Usual Dosage: Adults: One 100 mg capsule every 12 hours with
food. See package insert for full prescribing information.

Store at 20° to 25°C (68° to 77°F); excursions permitted between 15°
to 30°C (59° to 86°F) [see USP Controlled Room Temperature].

Keep this and all drugs out of reach of children.

FOR YOUR PROTECTION: Do not use if blister is torn or broken.

The drug product contained in this package is from
NDC # 65162-478, Amneal Pharmaceuticals LLC.

Distributed by:
American Health Packaging
Columbus, Ohio 43217

763365
0463365/0423

NDC 60687- 633-01

Nitrofurantoin
Capsules, USP
(monohydrate/macrocrystals)

100 mg

100 Capsules (10 x 10)                Rx Only

URINARY TRACT ANTIBACTERIAL

Each Capsule Contains:
The equivalent of 100 mg of nitrofurantoin, USP in the form of 25 mg
of nitrofurantoin macrocrystals and 75 mg of nitrofurantoin monohydrate.

Usual Dosage: Adults: One 100 mg capsule every 12 hours with food.
See package insert for full prescribing information.

Store at 20° to 25°C (68° to 77°F); excursions permitted between
15° to 30°C (59° to 86°F) [see USP Controlled Room Temperature].

FOR YOUR PROTECTION: Do not use if blister is torn or broken.

The drug product contained in this package is from NDC # 65162-478,
Amneal Pharmaceuticals LLC.

Distributed by: American Health Packaging, Columbus, Ohio 43217

763301
0463301/0924

Nitrofurantoin
Capsules, USP (monohydrate/
macrocrystals)     100 mg