Nitrofurantoin
Brand names Furadantin, Macrobid, Macrodantin
Used in the following combined preparations None
GENERAL INFORMATION
Nitrofurantoin is an antibacterial drug that is prescribed to treat urinary tract infections. The drug reaches high levels in the urinary tract where the bacteria are concentrated. Nitrofurantoin acts quickly, usually curing the infection within days.
Unfortunately, this drug produces adverse effects in about 10 per cent of people taking it, the most common of which is stomach irritation. This can be alleviated to a certain extent by taking the drug with food. Nitrofurantoin may cause toxic effects in the lungs and /or the nervous system in some cases; it may also affect liver function, leading to jaundice. Serious adverse effects are much more likely in people with reduced kidney function since drug levels build up in the body.
INFORMATION FOR USERS
Your drug prescription is tailored for you. Do not alter dosage without checking with your doctor.
How taken
Tablets, capsules, SR-capsules, liquid.
Frequency and timing of doses
3-4 x daily with food; once daily (prevention); 2 x daily (SR-capsules).
Dosage range
Adults 50-100mg daily at bedtime (prevention); 200-400mg daily (treatment). Children Reduced dose necessary according to age and weight.
Onset of effect
4-6 hours.
Duration of action
6-12 hours.
Diet advice
None.
Storage
Keep in a closed container in a cool, dry place out of the reach of children. Protect from light.
Missed dose
Take as soon as you remember. If your next dose is due within 3 hours, take a single dose now and skip the next.
Stopping the drug
Take the full course. Even if you feel better, the original infection may still be present, and symptoms may recur if treatment is stopped too soon.
Exceeding the dose
An occasional unintentional extra dose is unlikely to be a cause for concern. But if you notice any unusual symptoms, or if a large overdose has been taken, notify your doctor.
QUICK REFERENCE
Drug group Antibacterial drug
Overdose danger rating Low
Dependence rating Low
Prescription needed Yes
Available as generic Yes
POSSIBLE ADVERSE EFFECTS
Nitrofurantoin has a number of serious adverse effects that may make it necessary to stop taking the drug. The more common adverse effects, such as loss of appetite, nausea, and vomiting, tend to diminish as your body adjusts to the drug.
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Symptom/effect
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Frequency
Common
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Rare
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Discus, doctor
Only if severe
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with
In all cases
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Stop taking drug now
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Call
doctor
now
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Loss of appetite
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•
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■
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Nausea/vomiting
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•
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■
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Jaundice
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•
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■
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▲
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1
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Headache
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•
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■
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|
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Rash
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•
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■
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A
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Numb/tingling face
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•
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■
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▲
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Unexplained fever
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•
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■
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▲
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Shortness of breath
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•
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■
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▲
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1
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INTERACTIONS
Probenecid
The risk of adverse effects is increased when nitrofurantoin is taken in conjunction with probenecid.
Nalidixic acid
This drug reduces the antibacterial effect of nitrofurantoin.
SPECIAL PRECAUTIONS
Be sure to tell your doctor if:
▼ You have long-term liver or kidney problems.
▼ You have diabetes.
You have anaemia.
▼ You have a lung disorder.
▼ You have glucose-6-phosphate dehydrogenase (G6PD) deficiency.
▼ You are taking other medications.
Pregnancy
▼ Safety in pregnancy not established. Discuss with your doctor.
Breast-feeding
▼ The drug passes into the breast milk and may cause anaemia in G6PD-deficient infants. Discuss with your doctor.
Infants and children
▼ Reduced dose necessary.
Over 60
▼ No special problems.
Driving and hazardous work
▼ No known problems.
Alcohol
No known problems.
PROLONGED USE
Nitrofurantoin is not usually prescribed for long periods. If it is taken long term as a preventative measure, signs of toxic effects should be watched for.
Monitoring
Blood tests to check liver function may be carried out.
