Consumer medicine information

APO-Nitrofurantoin

Nitrofurantoin

BRAND INFORMATION

Brand name

APO-Nitrofurantoin

Active ingredient

Nitrofurantoin

Schedule

What is in this leaflet

This leaflet answers some common questions about this medicine. It does not contain all the available information. It does not take the place of talking to your doctor or pharmacist.

All medicines have risks and benefits. Your doctor has weighed the risks of you taking this medicine against the benefits they expect it will have for you.

If you have any concerns about taking this medicine, ask your doctor or pharmacist.

Keep this leaflet with the medicine. You may need to read it again.

What this medicine is used for

Nitrofurantoin is used to treat infections of the urinary system caused by bacteria, such as bladder infections.

It is an antibiotic which belongs to a group of medicines called nitrofurans. It works by killing or stopping the growth of the bacteria and other organisms causing these infections.

Ask your doctor if you have any questions about why this medicine has been prescribed for you. Your doctor may have prescribed it for another reason.

This medicine is not addictive.

This medicine is only with a doctor's prescription.

Before you take this medicine

When you must not take it

Do not take this medicine if you have an allergy to:

any medicine containing nitrofurantoin or any other nitrofuran
any of the ingredients listed at the end of this leaflet.

Some of the symptoms of an allergic reaction may include:

shortness of breath
wheezing or difficulty breathing
swelling of the face, lips, tongue or other parts of the body
rash, itching or hives on the skin

Do not take this medicine if you have or have had severe kidney problems.

Do not take this medicine if you are pregnant. It may affect your developing baby if you take it during pregnancy.

Do not give this medicine to a child under the age of 1 month. Safety and effectiveness in children younger than 1 month have not been established.

Do not take this medicine after the expiry date printed on the pack or if the packaging is torn or shows signs of tampering. If it has expired or is damaged, return it to your pharmacist for disposal.

If you are not sure whether you should start taking this medicine, talk to your doctor.

Before you start to take it

Tell your doctor if you have allergies to any other medicines, foods, preservatives or dyes.

Tell your doctor if you have or have had any of the following medical conditions:

kidney problems
G-6-PD deficiency, a condition where you lack an enzyme in red blood cells (occurs in a very small number of people of African descent or Mediterranean or Near Eastern origin)
anaemia (a blood disorder)
diabetes
vitamin B deficiency

Tell your doctor if you are pregnant or plan to become pregnant or are breastfeeding. Your doctor can discuss with you the risks and benefits involved.

If you have not told your doctor about any of the above, tell them before you start taking this medicine.

Taking other medicines

Tell your doctor or pharmacist if you are taking any other medicines, including any that you get without a prescription from your pharmacy, supermarket or health food shop.

Some medicines and this one may interfere with each other. These include:

phenobarbitone, used to treat epilepsy
medicines used to treat gout, such as probenecid and sulfinpyrazone
antacids, used to treat heartburn, indigestion or reflux
agents used to make the urine more acidic, such as ammonium chloride tablets
agents used to make the urine more alkaline, such as sodium bicarbonate

These medicines may be affected by nitrofurantoin or may affect how well it works. You may need different amounts of your medicines, or you may need to take different medicines.

Your doctor and pharmacist have more information on medicines to be careful with or avoid while taking this medicine.

How to take this medicine

Follow all directions given to you by your doctor or pharmacist carefully. They may differ from the information contained in this leaflet.

If you do not understand the directions, ask your doctor or pharmacist for help.

How much to take

Adults

If you already have an infection:
The usual dose is 1 capsule (either the 50 mg or 100 mg strength) four times daily.

To prevent an infection:
The usual dose is 1 capsule (either the 50 mg or 100 mg strength) taken at night.

Children
The dose for children will depend on their body weight. The usual dose is 1.25 to 1.75 mg/kg of body weight given four times a day. Your doctor will calculate the proper dose considering the age and weight of the child, and how severe the infection is.

How to take it

Swallow the capsules with a full glass of water.

When to take it

Take your medicine at about the same time each day. Taking it at the same time each day will have the best effect. It will also help you remember when to take it.

Take your medicine immediately after food or a glass of milk. If taken on an empty stomach it may cause a stomach upset.

How long to take it

Continue taking your medicine until you finish the bottle or until your doctor recommends.

Do not stop taking your medicine earlier than this, even if you are feeling better.

Check with your doctor if you are not sure how long you should be takingthe medicine.

If you forget to take it

If it is almost time to take your next dose, skip the dose you missed and take your next dose when you are meant to.

Otherwise, take it as soon as you remember, and then go back to taking your medicine as you would normally.

Do not take a double dose to make up for the dose that you missed. This may increase the chance of you getting an unwanted side effect.

If you are not sure what to do, ask your doctor or pharmacist.

If you have trouble remembering to take your medicine, ask your pharmacist for some hints.

If you take too much (overdose)

Immediately telephone your doctor or the Poisons Information Centre (telephone 13 11 26) for advice or go to Accident and Emergency at the nearest hospital, if you think that you or anyone else may have taken too much of this medicine. Do this even if there are no signs of discomfort or poisoning.

You may need urgent medical attention.

While you are using this medicine

Things you must do

Tell your doctor if the symptoms of your infection do not improve, or if they become worse.

If you are about to be started on any new medicine, remind your doctor and pharmacist that you are taking this medicine.

Tell any other doctors, dentists, and pharmacists who treat you that you are taking this medicine.

If you are going to have surgery, tell the surgeon or anaesthetist that you are taking this medicine. It may affect other medicines usedduring surgery.

If you become pregnant or start to breastfeed while taking this medicine, tell your doctor immediately.

If you are about to have any urine or blood tests, tell your doctor that you are taking this medicine. It may interfere with the results of some tests.

Keep all your doctor's appointments so that your progress can be checked. Your doctor may do some tests from time to time to make sure the medicine is working and to prevent unwanted side effects.

Things you must not do

Do not take this medicine to treat any other complaints unless your doctor tells you to.

Do not give your medicine to anyone else, even if they have the same condition as you.

Do not stop taking your medicine before you finish the bottle or until as advised by your doctor, even if you are feeling better. If you do not complete the full course prescribed by your doctor, all of the bacteria causing your infection may not be killed. These bacteria may continue to grow and multiply so that your infection may not clear completely or may return.

Do not take antacid preparations at the same time as this medicine. These preparations may affect how well nitrofurantoin works.

Things to be careful of

When taking this medicine, your urine may turn brown. This is temporary and not associated with any serious effects.

Nitrofurantoin may interfere with the normal production of spermcells. This is reversible. If this causes you any concerns, please speak to your doctor.

Side effects

Tell your doctor or pharmacist as soon as possible if you do not feel well while you are taking this medicine.

All medicines can have side effects. Sometimes they are serious, most of the time they are not. You may need medical attention if you get some of the side effects.

If you are over 65 years of age you may have an increased chance of getting side effects.

Do not be alarmed by the following lists of side effects. You may not experience any of them.

Ask your doctor or pharmacist to answer any questions you may have.

Tell your doctor or pharmacist if you notice any of the following and they worry you:

nausea and vomiting
diarrhoea
headache and dizziness
drowsiness and altered mood
feeling weak

The above list includes the more common side effects of your medicine. They are usually mild and short-lived.

Tell your doctor as soon as possible if you notice any of the following:

diarrhoea (which may occur up to several weeks after finishing the course)
numbness or tingling in any area of the body
confusion, hallucinating or illusions
hepatitis, an inflammation of the liver which can result in yellowing of the skin and eyes, lower back pain, dark urine, tiredness and a general feeling of being unwell
fever and chills
chest pain, difficulty with breathing and cough
skin rash and itchiness
asthma attack
sore throat or gums and a continual feeling of tiredness

The above list includes serious side effects that may require medical attention. Serious side effects are rare.

If any of the following happen, tell your doctor immediately or go to Accident and Emergency at your nearest hospital:

symptoms of an allergic reaction including cough, shortness of breath, wheezing or difficulty breathing; swelling of the face, lips, tongue, throat or other parts of the body; rash, itching or hives on the skin

The above list includes very serious side effects. You may need urgent medical attention or hospitalisation. These side effects are very rare.

Tell your doctor or pharmacist if you notice anything that is making you feel unwell.

Other side effects not listed above may also occur in some people.

Storage and Disposal

Storage

Keep your capsules in the bottle until it is time to take them. If you take the capsules out of the bottle, they may not keep well.

Keep your medicine in a cool dry place where the temperature stays below 25°C.

Do not store this medicine or any other medicine in the bathroom or near a sink. Do not leave it on a window sill or in the car. Heat and dampness can destroy some medicines.

Keep it where children cannot reach it. A locked cupboard at least one-and-a-half metres above the ground is a good place to store medicines.

Disposal

If your doctor tells you to stop taking this medicine or the expiry date has passed, ask your pharmacist what to do with any medicine that is left over.

Product description

What it looks like

APO-Nitrofurantoin is available as 50 mg and 100 mg capsules.

These are supplied in bottles of 4 (50 mg only) or 30 capsules.

Nitrofurantoin 50 mg Capsules
Yellow, opaque cap and white opaque body, size “3" plain, hard gelatin capsule filled with yellow coloured powder. AUST R 299383.

Nitrofurantoin 100 mg Capsules
Yellow, opaque cap and yellow opaque body, size "2", plain, hard gelatin capsule filled with yellow coloured powder. AUST R 299385.

Ingredients

APO-Nitrofurantoin capsules contain either 50 mg or 100 mg of nitrofurantoin macrocrystals as the active ingredient.

This medicine also contains the following:

pregelatinised maize starch
purified talc
lactose monohydrate
magnesium stearate
gelatin
purified water
titanium dioxide
quinoline yellow
sunset yellow FCF

This medicine contains sugars as lactose. It also contains sulfites.

This medicine is free-from gluten.

Supplier

This medicine is supplied in Australia by:

Apotex Pty Ltd
16 Giffnock Avenue
Macquarie Park NSW 2113
Tel: (02) 8877 8333

This leaflet was prepared in December 2021.

Published by MIMS January 2022

BRAND INFORMATION

Brand name

APO-Nitrofurantoin

Active ingredient

Nitrofurantoin

Schedule

1 Name of Medicine

Nitrofurantoin.

2 Qualitative and Quantitative Composition

Each APO-Nitrofurantoin capsule contains either 50 mg or 100 mg of nitrofurantoin.
Nitrofurantoin is a synthetic antibacterial nitrofuran derivative. It occurs as lemon yellow crystals, or fine powder, and is very slightly soluble in water or alcohol. However, solubility of the drug in water and urine increases with rises in pH. Nitrofurantoin darkens on exposure to light or to alkali and is decomposed upon contact with metals other than stainless steel or aluminium. In view of this, the drug should not be exposed to light.

Note.

Nitrofurantoin macrocrystals is a larger crystal form of nitrofurantoin. The absorption of nitrofurantoin macrocrystals is slower and the excretion is somewhat less, when the two are compared. The reduced incidence of gastrointestinal intolerance with nitrofurantoin macrocrystals is probably due to delayed and decreased absorption; this however does not significantly reduce clinical effectiveness. A number of patients who cannot tolerate nitrofurantoin tablets can take nitrofurantoin macrocrystals capsules without nausea.

Excipient with known effect.

Lactose monohydrate. For a full list of excipients, see Section 6.1 List of Excipients.

3 Pharmaceutical Form

Nitrofurantoin 50 mg capsule.

Yellow, opaque cap and white opaque body, size "3" plain, hard gelatin capsule filled with yellow coloured powder.

Nitrofurantoin 100 mg capsules.

Yellow, opaque cap and yellow opaque body, size "2", plain, hard gelatin capsule filled with yellow coloured powder.

4 Clinical Particulars

4.1 Therapeutic Indications

Treatment of urinary tract infections such as cystitis and pyelitis when due to susceptible pathogens. Nitrofurantoin does not reach effective levels in plasma and consequently is not indicated for cortical or perinephric abscesses and in cases of prostatitis.

4.2 Dose and Method of Administration

To be taken with food or milk.

Dosage.

Adults.

50-100 mg four times a day. Do not exceed 400 mg daily.

Prophylactic therapy.

50 mg or 100 mg nocte.

Children.

Should be calculated on the basis of 5-7 mg/kg body weight per 24 hours to be given in divided doses four times a day.
APO-Nitrofurantoin should not be administered to infants under one month of age.
Therapy should be continued for at least one week and for at least 3 days after sterility of the urine is obtained. Continued infection indicates the need for re-evaluation. If the drug is to be used for prophylactic or for long-term suppressive therapy, consideration should be given to finding the lowest effective dose.

4.3 Contraindications

Anuria and oliguria or extensive impairment of renal function (creatinine clearance under 60 mL/min or clinically significant elevated serum creatinine); hypersensitivity to furan derivatives; nitrofurantoin should not be administered to pregnant women during labour and delivery, or when the onset of labour is imminent or to infants under one month of age because of the possibility of producing a haemolytic anaemia due to immature enzyme systems (glutathione instability) in the early neonatal period.

4.4 Special Warnings and Precautions for Use

Peripheral neuropathy.

Peripheral neuropathy (including optic neuritis), which may become severe or irreversible, has occurred. Fatalities have been reported. Conditions such as renal impairment (creatinine clearance under 60 mL/min or clinically significant elevated serum creatinine), anaemia, 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. If numbness or tingling occurs in any area, administration of the drug should be discontinued (see Section 4.8 Adverse Effects (Undesirable Effects), Neurological).

Hepatic reactions.

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 liver function. If hepatitis occurs, the drug should be withdrawn immediately and appropriate measures should be taken (see Section 4.8 Adverse Effects (Undesirable Effects), Hepatic).

Pulmonary reactions.

Acute, subacute or chronic pulmonary reactions have been observed in patients treated with nitrofurantoin. These reactions can be life threatening; therefore if they occur treatment should be stopped immediately. 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 Section 4.8 Adverse Effects (Undesirable Effects), a) Pulmonary hypersensitivity).

Impaired renal function or acidosis.

In the presence of impairment of renal function or acidosis, administer APO-Nitrofurantoin with caution. If employed under such circumstances the blood pH, CO₂-content or combining power and urea nitrogen or non-protein nitrogen should be followed closely. This is particularly important if treatment is continued beyond fourteen days.

Haemolytic anaemia.

Haemolytic anaemia of the primaquine-sensitivity type has been induced by nitrofurantoin. The haemolysis appears to be linked to a glucose-6-phosphate dehydrogenase deficiency in the affected patients' red blood cells. This deficiency is found in 10% of African descent individuals and in a small percentage of ethnic groups of Mediterranean and Near Eastern origin. G6PD deficiency has also been reported occasionally amongst Caucasian groups. Any sign of haemolysis is an indication to discontinue the drug. Haemolysis ceases when the drug is withdrawn.

Colitis.

Antibiotic associated pseudomembranous colitis has been reported with many antibacterials including sporadic reports with nitrofurantoin. A toxin produced with Clostridium difficile appears to be the primary cause. The severity of the colitis may range from mild to life threatening. It is important to consider this diagnosis in patients who develop diarrhoea or colitis in association with antibiotic use (this may occur up to several weeks after cessation of antibiotic therapy). Mild cases usually respond to drug discontinuation alone. However, in moderate to severe cases appropriate therapy with a suitable oral antibacterial agent effective against Clostridium difficile should be considered. Fluids, electrolytes and protein replacement should be provided when indicated. Drugs which delay peristalsis, e.g. opiates and diphenoxylate with atropine may prolong and/or worsen the condition and should not be used.
Patients should be advised that nitrofurantoin may cause brownish discolouration of the urine.

Use in the elderly.

No data available

Paediatric use.

No data available.

Effects on laboratory tests.

Nitrofurantoin can interfere with certain laboratory tests e.g. serum bilirubin (false positive or spuriously high reading), urine creatinine (false positive, or accurate readings cannot be made, due to interference), serum urea (no accurate reading due to interference), urine glucose (false positive or spuriously high readings). Urine glucose tests dependent on glucose oxidase are not affected e.g. Clinistix and Testape.

4.5 Interactions with Other Medicines and Other Forms of Interactions

The excretion of nitrofurantoin is decreased by acidifying drugs, whereby potentiation of nitrofurantoin may occur. Conversely, alkalinising drugs increase the rate of excretion and may diminish the effect of nitrofurantoin. Phenobarbitone has an inhibitory action on nitrofurantoin. Uricosuric drugs, such as probenecid and sulfinpyrazone, can inhibit renal tubular secretion of nitrofurantoin. The resulting increase in nitrofurantoin serum levels may increase toxicity and the decreased urinary levels could lessen its efficacy as a urinary tract antibacterial.
Antacids reduce the potency of the drug. Patients should be advised not to use antacid preparations at the same time as nitrofurantoin.

4.6 Fertility, Pregnancy and Lactation

Effects on fertility.

Rats given large doses of nitrofurantoin have developed lesions in seminiferous tubules which vary from atrophy to arrest of spermatogenesis. The arrest of spermatogenesis was reversible and treated male rats sired normal litters after recovery.
In man, nitrofurantoin can decrease sperm counts and produce abnormal testicular histology suggestive of arrested spermatogenesis.
(Category A)

Short term therapy.

Nitrofurantoin has had widespread clinical use for many years. Studies, to date, have not shown a potential for nitrofurantoin to cause birth defects.
Nitrofurantoin crosses the placenta, and caution should be exercised when administering nitrofurantoin at term or to infants under one month of age because of the possibility of producing a haemolytic anaemia in patients with glucose-6-phosphate dehydrogenase (G6PD) deficiency due to immature enzyme systems in the early neonatal period.
Although studies have shown that the amount of nitrofurantoin excreted in breast milk after normal therapeutic doses is negligible, the possibility of producing a haemolytic anaemia due to immature enzyme systems in the early neonatal period should be considered when administering the drug to nursing mothers.

4.7 Effects on Ability to Drive and Use Machines

Nitrofurantoin may cause dizziness and drowsiness and the patient should not drive or operate machinery if affected this way.

4.8 Adverse Effects (Undesirable Effects)

Gastrointestinal.

Nausea with associated anorexia and emesis is the most common adverse effect of nitrofurantoin therapy. This can be reduced by taking the drug with food or milk. Less frequent are abdominal pain and diarrhoea and, rarely, hepatitis - these latter dose-related toxic effects can be minimised by reduction of the dose especially in females on long term treatment. Dyspepsia, flatulence and constipation have also been reported.

Neurological.

Polyneuropathy, (including optic neuritis) which starts peripherally with initial sensory loss and paraesthesia but progresses to motor loss often with severe muscle atrophy, has occurred during nitrofurantoin therapy. A predisposing condition in most of these patients was renal failure which often was accompanied by anaemia, diabetes, electrolyte imbalance, vitamin B deficiency and debilitating disease. After stopping nitrofurantoin therapy, further deterioration is generally halted and total or partial regression occurs in almost 80% of those affected. These reactions may be severe or irreversible, but are rarely fatal. Polyneuropathy occurs in adults and children.
If numbness or tingling occurs in any area, administration of the drug should be discontinued. Headache, dizziness, nystagmus, drowsiness, asthenia, vertigo, amblyopia, depression, euphoria, confusion, psychotic reactions and benign intracranial hypertension have also been reported.

Hepatic.

Hepatic reactions can occur, including hepatitis, cholestatic jaundice, chronic active hepatitis and hepatic necrosis. These reactions can be life threatening, therefore if they occur treatment should be stopped immediately. Chronic hepatic reactions can develop insidiously, but usually occur in patients on therapy for 5 months or longer. Patients on prolonged therapy should be re-examined at intervals not exceeding 6 months.

Hypersensitivity reactions of several types have been reported.

a) Pulmonary hypersensitivity.

Can be acute, sub-acute or chronic. These reactions can be life threatening; therefore if they occur treatment should be stopped immediately.
Acute reactions are commonly manifested by fever, chills, cough, chest pain, dyspnoea and pulmonary infiltration with consolidation and pleural effusion on X-ray and eosinophilia. The acute reaction usually occurs in the first week of therapy and resolves on withdrawal of the drug.
Sub-acute or chronic pulmonary reactions are associated with prolonged therapy. Insidious onset of malaise, dyspnoea on exertion, cough, cyanosis, altered pulmonary function and roentgenographic and histological findings of diffuse interstitial pneumonitis and fibrosis are common manifestations. Patients on prolonged therapy should be re-examined at intervals not exceeding 6 months.
The severity of chronic pulmonary reactions and their degree of resolution appear to be related to the duration of therapy after the first clinical signs appear. Pulmonary function may be impaired permanently, even after cessation of therapy. The risk is greater when chronic pulmonary reactions are not recognised early.
Changes in ECG may occur associated with pulmonary reactions. Cardiopulmonary failure leading to collapse and death has been reported.

b) Dermatological reactions.

Exfoliative dermatitis, erythema multiforme, (including Stevens-Johnson syndrome) maculopapular, erythematous or eczematous eruptions and transient alopecia may occur.

c) Other sensitivity reactions.

Have included lupus like syndrome and anaphylaxis, asthma attacks in patients with a history of asthma, urticaria, rash, pruritis, drug fever, angioedema, drug allergy, sialadenitis, pancreatitis and arthralgia.

Haematological reactions.

Haemolytic anaemia, leucopenia, granulocytopenia, eosinophilia, thrombocytopenia, agranulocytosis, aplastic anaemia and megaloblastic anaemia. Return of the blood picture to normal has followed cessation of therapy.

Miscellaneous reactions.

As with other microbial agents, urinary tract superinfections by resistant organisms (e.g. Pseudomonas or Candida) can occur. There are sporadic reports of Clostridium difficile superinfections, or pseudomembranous colitis, with the use of nitrofurantoin.
The most frequent laboratory test abnormalities reported with use of nitrofurantoin are as follows: eosinophilia, increased AST (SGOT), increased ALT (SGPT), decreased haemoglobin, increased serum phosphate.
The following laboratory adverse events also have been reported with the use of nitrofurantoin: glucose-6-phosphate dehydrogenase deficiency anaemia (see Section 4.4 Special Warnings and Precautions for Use), agranulocytosis, leukopenia, granulocytopenia, haemolytic anaemia, thrombocytopenia, megaloblastic anaemia. In most cases, these hematologic abnormalities resolved following cessation of therapy. Aplastic anaemia has been reported rarely.

Reporting suspected adverse effects.

Reporting suspected adverse reactions after registration of the medicinal product is important. It allows continued monitoring of the benefit-risk balance of the medicinal product. Healthcare professionals are asked to report any suspected adverse reactions at http://www.tga.gov.au/reporting-problems and contact Apotex Medical Information Enquiries/Adverse Drug Reaction Reporting on 1800 195 055.

4.9 Overdose

There are very little data available on toxicity of nitrofurantoin after overdose. No toxic serum levels have been established.

Symptoms.

Symptoms expected would be mainly extensions of side effects. Occasional incidents of acute overdosage have not resulted in any specific symptoms other than vomiting.

Treatment.

There is no specific treatment of overdosage and no antidotes are recommended. Treatment is essentially symptomatic and supportive.
As nitrofurantoin is excreted rapidly in the urine administration of adequate amounts of fluid will hasten excretion of the absorbed drug. In a patient with normal renal function 50 to 250 mg/L are considered normal urine levels after taking a therapeutic dose.
For information on the management of overdose, contact the Poisons Information Centre on 131126 (Australia).

5 Pharmacological Properties

5.1 Pharmacodynamic Properties

Mechanism of action.

APO-Nitrofurantoin is bacteriostatic at low concentrations (1:100,000 to 1:200,000) and in vitro is considered to be bactericidal in higher concentrations. Its presumed mode of action is based upon its interference with several bacterial enzyme systems.
Nitrofurantoin is active against Gram-positive and Gram-negative urinary tract pathogens, particularly E. coli, but Ps. aeruginosa and some Klebsiella, Aerobacter and Proteus strains are insensitive. See Table 1.

Urine levels reached with normal therapeutic doses are usually in the range of 15-46 micrograms/mL and levels above the MIC for the most sensitive organisms are detectable for about 6 hours.
Bacteria develop only a limited resistance to furan derivatives.

Clinical trials.

No data available.

5.2 Pharmacokinetic Properties

Absorption.

Nitrofurantoin is well absorbed orally. The peak plasma level appears 1-2 hours after an oral dose and has been found not to exceed 2.5 micrograms/mL.

Distribution.

25-60% of nitrofurantoin is bound to serum proteins. The plasma half life of the drug is 20 min.
The average urinary drug recoveries following a therapeutic dose regimen (100 mg four times daily for 7 days) were reported to be 37.9% (day 1) and 35% (day 7) for the macrocrystalline dosage form.

Metabolism and excretion.

Nitrofurantoin is excreted rapidly in the urine, mainly in the unchanged form, the only metabolic pathway of importance involving reduction of the nitro group. Excretion is via the kidney both in the glomerular filtrate and by tubular secretion.

5.3 Preclinical Safety Data

Genotoxicity.

It may be concluded that although nitrofurantoin has genotoxic properties in vitro, it is of low genotoxic potential in whole animals. Thus it is unlikely that the increased tumour incidences seen in male rats are due to genotoxic action.

Carcinogenicity.

Nitrofurantoin has caused increases in the incidence of renal tubular cell adenomas when administered to male rats at 65-125 mg/kg/day for 2 years. The biological significance of this remains to be established. When administered to female mice at 375 mg/kg/day for 2 years, nitrofurantoin induced an increase in the incidence of benign ovarian tumours. It would appear that this effect may be secondary to its primary toxic activity of inducing ovarian atrophy and sterility.

Mutagenicity.

Nitrofurantoin is mutagenic in certain bacterial systems and although it is not known how far this relates to the clinical situation the possibility of a permanent mutagenic effect on spermatozoa-producing cells requires that careful consideration be given to its use in young males.

6 Pharmaceutical Particulars

6.1 List of Excipients

Capsule content.

Lactose monohydrate, pregelatinised maize starch, purified talc, magnesium stearate.

Capsule shell.

Gelatin, purified water, quinoline yellow, sunset yellow FCF, titanium dioxide.

6.2 Incompatibilities

See Section 4.5 Interactions with Other Medicines and Other Forms of Interactions.

6.3 Shelf Life

2 years.

6.4 Special Precautions for Storage

Store below 25°C.

6.5 Nature and Contents of Container

HDPE bottle with a PP child resistant screw cap containing the tablets which is covered by Cotton-9gm coiler.

APO-Nitrofurantoin capsules 50 mg.

Bottle packs of 4's count and 30's count.
AUST R 299383.

APO-Nitrofurantoin capsules 100 mg.

Bottle packs of 30's count
AUST R 299385.
Not all pack sizes may be marketed.

6.6 Special Precautions for Disposal

In Australia, any unused medicine or waste material should be disposed of by taking to your local pharmacy.

6.7 Physicochemical Properties

Nitrofurantoin has the following chemical structure:

Chemical structure.

Chemical name: 1-[[(5-nitrofuran-2-yl)methylene]amino]imidazolidine-2,4-dione.
Molecular formula: C₈H₆N₄O₅.
Molecular weight: 238.2.

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APO-Nitrofurantoin 100 mg Capsules

APO-Nitrofurantoin 50 mg Capsules