Indications & Uses
Nitrofurantoin (including the microcrystalline form) is used both to treat and to prevent acute or recurrent uncomplicated infections of the lower urinary tract, as well as pyelitis, whether these arise spontaneously or occur after a surgical procedure. It is particularly suited to treating infections caused by susceptible organisms such as *Escherichia coli*, enterococci, staphylococci, *Citrobacter*, *Klebsiella*, and *Enterobacter*.
Pharmacology
Each capsule contains two forms of nitrofurantoin. Twenty-five percent is macrocrystalline nitrofurantoin, which dissolves and is absorbed more slowly than nitrofurantoin monohydrate. The remaining 75 percent is nitrofurantoin monohydrate, held in a powder blend that, on contact with gastric and intestinal fluids, forms a gel matrix releasing nitrofurantoin gradually over time. This capsule is highly soluble in urine, which it may turn brown. Taking it with food raises the bioavailability of nitrofurantoin by approximately 40 percent.
Dosage Reference
Reference Information Only
Dosages shown are general references from official sources. Always consult your doctor or pharmacist for personalized dosing.
Adults:
Adults and children over 12 years of age
For acute or recurrent uncomplicated urinary tract infections and pyelitis, the usual dose is one Umactin-BD 100 capsule, which contains Nitrofurantoin Modified Release 100 mg, taken 2 times daily for 7 days.
For surgical prophylaxis, take one Umactin-BD 100 capsule (Nitrofurantoin Modified Release 100 mg) 2 times daily on the day of the procedure and for 3 days after it.
Children and infants over 3 months of age
For acute urinary tract infections, the dose is Nitrofurantoin 3 mg/kg per day, given as Umactin Suspension 0.6 ml/kg, split into 4 doses over 7 days.
For long term suppression of UTI, the dose is Nitrofurantoin 1 mg/kg, given as Umactin Suspension 0.25 ml/kg, once a day.
Elderly
As long as there is no significant renal impairment, the dose for older people is the same as for any normal adult. Nitrofurantoin is contraindicated where renal impairment is significant, so kidney function matters here.
Side Effects
Respiratory: If any of these reactions occur, the drug should be stopped. Acute pulmonary reactions can develop, and subacute reactions may take several months to settle once the drug has been withdrawn. Chronic pulmonary reactions are rare and are seen in patients who have been on continuous therapy for 6 months or longer; they are more common in elderly patients. ECG changes have been seen alongside these pulmonary reactions. Even minor symptoms such as fever, chills, cough and breathlessness may be meaningful and should not be ignored. Hepatic: Liver reactions, including cholestatic jaundice and chronic active hepatitis, occur rarely. Treatment should be stopped as soon as there is any sign of liver toxicity. Neurological: Peripheral neuropathy, including optic neuritis, with both sensory and motor symptoms, has been reported infrequently and may become severe or irreversible. Treatment should be stopped at the first sign of nerve involvement. Gastrointestinal: Nausea and loss of appetite have been reported.
Cautions & Contraindications
Warnings & Precautions
Nitrofurantoin does not effectively treat parenchymal infections of a unilaterally nonfunctioning kidney. In recurrent or severe cases, a surgical cause for the infection should be ruled out. Since underlying conditions may mask adverse reactions, Nitrofurantoin should be used cautiously in patients with pulmonary disease, hepatic dysfunction, neurological disorders, and allergic diathesis. Peripheral neuropathy, which may become severe or irreversible and can be life threatening, has occurred with this drug. Treatment should therefore be stopped at the very first signs of nerve involvement, such as tingling or numbness (paraesthesiae). Caution is also needed in patients with anaemia, diabetes mellitus, electrolyte imbalance, debilitating conditions, and vitamin B deficiency, particularly of folate. Chronic pulmonary reactions can develop gradually and without obvious warning, and they tend to occur more often in elderly patients, so close monitoring of pulmonary status is warranted during long-term therapy. In patients with suspected glucose-6-phosphate dehydrogenase deficiency, Nitrofurantoin should be discontinued at the first sign of haemolysis. Gastrointestinal reactions may be minimised by taking the drug with food or milk, or by adjusting the dosage.
Contraindications
Nitrofurantoin should not be used in patients with renal impairment (creatinine clearance under 60 ml/minute) or elevated serum creatinine, in infants under 3 months of age, or in pregnant women at term (during labour and delivery). This last precaution is because of a theoretical risk of haemolytic anaemia in the foetus or newborn, arising from the immaturity of their red blood cell enzyme systems. It is also contraindicated in anyone with known hypersensitivity to nitrofurantoin or other nitrofuran-class drugs.
Pregnancy & Breastfeeding
Animal studies with Nitrofurantoin have shown no teratogenic effects, and the medicine has been in extensive clinical use since 1952, giving it a well-documented safety record in human pregnancy. It should still be used at the lowest dose appropriate for the specific indication, and only after careful assessment. Nitrofurantoin is contra-indicated in infants under 3 months of age and in pregnant women during labour and delivery, because of the possible risk of haemolysis in the infant's immature red blood cells. Since the drug is detected in trace amounts in breast milk, caution should be exercised when breastfeeding an infant known or suspected to have an erythrocyte enzyme deficiency.
⚠️ Talk to your doctor before taking any medicine during pregnancy or while breastfeeding.
Overdose
An overdose of Nitrofurantoin shows up as gastric irritation, nausea and vomiting. No specific antidote is known. If the tablets were taken recently, Nitrofurantoin can be removed by haemodialysis. The standard treatment is to induce emesis or to do gastric lavage. Full blood count, liver function and pulmonary function tests should be monitored. The patient should also keep up a high fluid intake, which helps the body pass the drug out in the urine.
⚠️ In an emergency call 999 or go to the nearest hospital emergency department.
Storage
Keep Nitrofurantoin in a cool, dry place and away from light.
Common questions about Macrogen 50 SR Capsule 37.5 mg
What is Macrogen 50 SR Capsule 37.5 mg Capsule?
Macrogen 50 SR Capsule 37.5 mg Capsule is a medicine that contains Nitrofurantoin + Nitrofurantoin Microcrystals. It is made by Renata PLC, Gazipur. It belongs to the Systemic Urinary Anti- infective group of medicines.
What is Macrogen 50 SR Capsule used for?
Nitrofurantoin (including the microcrystalline form) is used both to treat and to prevent acute or recurrent uncomplicated infections of the lower urinary tract, as well as pyelitis, whether these arise spontaneously or occur after a surgical procedure. It is particularly suited to treating infections caused by susceptible organisms such as *Escherichia coli*, enterococci, staphylococci, *Citrobacter*, *Klebsiella*, and *Enterobacter*.
What are the side effects of Macrogen 50 SR Capsule?
Respiratory: If any of these reactions occur, the drug should be stopped. Acute pulmonary reactions can develop, and subacute reactions may take several months to settle once the drug has been withdrawn.
Can I take Macrogen 50 SR Capsule during pregnancy or while breastfeeding?
Animal studies with Nitrofurantoin have shown no teratogenic effects, and the medicine has been in extensive clinical use since 1952, giving it a well-documented safety record in human pregnancy. It should still be used at the lowest dose appropriate for the specific indication, and only after careful assessment. Talk to your doctor before taking any medicine during pregnancy or while breastfeeding.
What happens if I take too much Macrogen 50 SR Capsule?
An overdose of Nitrofurantoin shows up as gastric irritation, nausea and vomiting. No specific antidote is known. In an emergency call 999 or go to the nearest hospital emergency department.
How should I store Macrogen 50 SR Capsule?
Keep Nitrofurantoin in a cool, dry place and away from light.
Do I need a prescription for Macrogen 50 SR Capsule?
Macrogen 50 SR Capsule is a prescription (Rx) medicine. Take it as your doctor advises.