Macrobid (Nitrofurantoin,Nitrofurantoin)

Uses

Macrobid (Nitrofurantoin,Nitrofurantoin) is specifically used for the treatment & prophylaxis of urinary tract infections when due to susceptible strains of Escherichia coli, Enterococci, Staphylococcus aureus, Staphylococcus saprophyticus and certain susceptible strains of Klebsiella and Enterobacter species.

Macrobid (Nitrofurantoin,Nitrofurantoin) is also used to associated treatment for these conditions: Acute Cystitis, Urinary Tract Infection

How Macrobid (Nitrofurantoin,Nitrofurantoin) works

Macrobid (Nitrofurantoin,Nitrofurantoin) is converted by bacterial nitroreductases to electrophilic intermediates which inhibit the citric acid cycle as well as synthesis of DNA, RNA, and protein.

Dosage

Macrobid (Nitrofurantoin,Nitrofurantoin) dosage

Tablet:

• Adults: 50-100 mg four times a day - the lower dosage level is recommended for uncomplicated urinary tract infections.
• Children: 5-7 mg/kg/day in four divided doses (contraindicated under one month of age). Therapy should be continued for one week or for at least 3 days after sterility of the urine is obtained.
• For long-term suppressive therapy in adults:a reduction of dosage to 50-100 mg at bedtime may be adequate. For long-term suppressive therapy in children, doses as low as 1 mg/kg per 24 hours, given in a single dose or in two divided doses, may be adequate.

SR Capsule:

• Adults and Children over 12 years: One 100 mg capsule every 12 hours for seven days.
• Genito-urinary surgical prophylaxis: One capsule twice daily on day of procedure and for next 3 days.

Suspension:

Children: 5-7 mg/kg/day in four divided doses (contraindicated under 1 month of age). The average dose of Macrobid (Nitrofurantoin,Nitrofurantoin)suspension for pediatric patients can be calculated as follows:-

• For 7 to 11 kg Body Weight patient: ½ (2.5 ml) teaspoonfuls (4 times daily)
• For 12 to 21 kg Body Weight patient: 1 (5 ml) teaspoonfuls (4 times daily)
• For 22 to 30 kg Body Weight patient: 1 ½ (7.5 ml) teaspoonfuls (4 times daily)
• For 31 to 41 kg Body Weight patient: 2 (10 ml) teaspoonfuls (4 times daily)

Therapy should be continued for one week or for at least 3 days after sterility of the urine is obtained.

For long-term suppressive therapy in children, doses as low as 1 mg/kg per 24 hours, given in a single dose or in two divided doses, may be adequate.

Macrobid (Nitrofurantoin,Nitrofurantoin) should be taken with food.

Side Effects

The most frequent clinical adverse events are nausea, headache, and flatulence. Other less occurred adverse events are diarrhea, dyspepsia, abdominal pain, constipation, emesis, dizziness, drowsiness

Toxicity

Symptoms of overdose include vomiting. In case of overdose, induce vomiting if it has not already occurred and increase fluid intake to promote urination. In extreme cases, nitrofurantoin can be removed from circulation by dialysis.

Precaution

If acute, sub-acute, or chronic pulmonary reactions occur, Macrobid (Nitrofurantoin,Nitrofurantoin) should be discontinued. Antacid preparations containing magnesium trisilicate should not be taken while taking Macrobid (Nitrofurantoin,Nitrofurantoin)

Interaction

Reduced excretion with probenecid or sulfinpyrazone. Absorption reduced by magnesium trisilicate. Antagonistic effects with quinolone antibacterials. Reduced effects with carbonic anhydrase inhibitors or urinary alkalinisers.

Food Interaction

• Take with food. Food decreases irritation and increases bioavailability.

Macrobid (Nitrofurantoin,Nitrofurantoin) Drug Interaction

Moderate: bifidobacterium infantis / lactobacillus acidophilusUnknown: aspirin, diphenhydramine, ubiquinone, duloxetine, apixaban, omega-3 polyunsaturated fatty acids, fluticasone nasal, pregabalin, metoprolol, polyethylene glycol 3350, mirabegron, acetaminophen / hydrocodone, levothyroxine, acetaminophen, cyanocobalamin, ascorbic acid, cholecalciferol, alprazolam, cetirizine

Macrobid (Nitrofurantoin,Nitrofurantoin) Disease Interaction

Major: colitis, G-6-PD deficiency, hepatotoxicity, renal dysfunctionModerate: peripheral neuropathy, respiratory

Volume of Distribution

Data regarding the volume of distribution in humans is scarce but it has been reported as 0.46L/kg in dogs.

Elimination Route

Macrobid (Nitrofurantoin,Nitrofurantoin) reaches a C_max of 0.875-0.963mg/L with an AUC of 2.21-2.42mg*h/L. It is 38.8-44.3% bioavailable. Taking nitrofurantoin with food increases the absorption and duration of therapeutic concentrations in the urine.

Half Life

The half life of nitrofurantoin is 0.72-0.78h.

Clearance

The clearance of nitrofurantoin is 16.7-19.4L/h.

Elimination Route

27-50% of an oral dose is excreted in the urine as unchanged nitrofurantoin. 90% of the total dose is eliminated in the urine.

Pregnancy & Breastfeeding use

Pregnancy Category B. There are no adequate and well-controlled studies in pregnant women. This drug should be used during pregnancy only if clearly needed.

Macrobid (Nitrofurantoin,Nitrofurantoin) has been detected in human breast milk in trace amounts. Because of the potential for serious adverse reactions from Macrobid (Nitrofurantoin,Nitrofurantoin) in nursing infants under one month of age, a decision should be made whether to discontinue nursing or to discontinue the drug, taking into account the importance of the drug to the mother

Contraindication

Anuria, oliguria, or significant impairment of renal function are contraindications. This drug is contraindicated in pregnant patients at 38-42 weeks, during labor and delivery. Macrobid (Nitrofurantoin,Nitrofurantoin) is also contraindicated in those patients with known hypersensitivity to Macrobid (Nitrofurantoin,Nitrofurantoin)

Acute Overdose

Occasional incidents of acute overdosage of Macrobid (Nitrofurantoin,Nitrofurantoin) have not resulted in any specific symptoms other than vomiting. Induction of emesis is recommended

Storage Condition

Store at 15-30° C

Innovators Monograph

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