Ofuran SR100 mg

Ofuran SR is a urinary antiseptic antibiotic that is FDA-approved and guideline-supported for the following use:

• Acute uncomplicated urinary tract infection (cystitis): Treatment of acute uncomplicated lower UTIs caused by susceptible strains of Escherichia coli, Staphylococcus saprophyticus, and certain other susceptible organisms including Enterococcus faecalis, Klebsiella, and Enterobacter species.
• Long-term suppressive therapy (prophylaxis): Guideline-supported use for prevention of recurrent uncomplicated urinary tract infections in selected patients, at lower once-daily or bedtime doses.

Ofuran SR is not effective for pyelonephritis, perinephric abscess, prostatitis, or other upper urinary tract or systemic infections, because it does not achieve adequate tissue or serum concentrations outside the urine. It is not indicated for infections outside the urinary tract.

Each unit of Nitrofurantoin contains Nitrofurantoin as the active ingredient, available in the following forms and strengths:

• Tablets: 100 mg
• Capsules: 50 mg and 100 mg
• Sustained-release (macrocrystalline) capsules: 50 mg and 100 mg (including combination monohydrate/macrocrystalline formulations of 100 mg)
• Oral suspension: 25 mg/5 mL

Ofuran SR is a synthetic nitrofuran-derivative antibacterial agent used specifically as a urinary antiseptic. Unlike most systemic antibiotics, Ofuran SR achieves therapeutic bactericidal concentrations mainly within the urine rather than in blood or tissue, which is why its use is restricted to lower urinary tract infections.

It is available as plain crystalline, macrocrystalline, and monohydrate/macrocrystalline formulations, which differ in their dissolution and absorption rates but are used for the same clinical indication.

Urinary anti-infective (urinary antiseptic); nitrofuran-class antibacterial agent, classified under Systemic Urinary Anti-infectives.

Mechanism of Action

Nitrofurantoin is bactericidal in urine. Bacterial flavoproteins reduce Nitrofurantoin to reactive intermediates that inactivate or alter bacterial ribosomal proteins and other macromolecules, inhibiting bacterial protein synthesis, aerobic energy metabolism, DNA, RNA, and cell wall synthesis. This broad, multi-target mechanism explains the low rate of acquired bacterial resistance to Nitrofurantoin.

Pharmacokinetics

Absorption of Nitrofurantoin is enhanced when taken with food. Approximately 20-25% of an oral dose is excreted unchanged in the urine within 24 hours, producing urinary concentrations well above the minimum inhibitory concentration for most susceptible urinary pathogens, while plasma concentrations remain very low (typically under 1 mcg/mL) because of rapid renal clearance and tissue distribution/metabolism. Because urinary excretion is essential for its antibacterial effect, adequate renal function is required for Nitrofurantoin to work and to avoid toxic accumulation.

Ofuran SR should be taken orally with food or milk to improve absorption and minimize gastrointestinal side effects such as nausea. Capsules and tablets should be swallowed whole; the oral suspension should be measured with an accurate dosing device and may be mixed with water, milk, or juice if needed. Doses should be spaced evenly through the day as prescribed.

• Magnesium trisilicate-containing antacids: Reduce both the rate and extent of absorption of Ofuran SR, potentially lowering its effectiveness; avoid co-administration where possible.
• Probenecid and sulfinpyrazone (uricosuric agents): These drugs inhibit renal tubular secretion of Ofuran SR, raising blood levels and increasing the risk of systemic toxicity while simultaneously reducing the urinary concentrations needed for antibacterial effect.
• Fluoroquinolone antibiotics: Ofuran SR may antagonize the antibacterial activity of fluoroquinolones; concurrent use is generally avoided.

Always inform your physician or pharmacist of all medicines, supplements, and antacids being used before starting Ofuran SR.

The following adverse effects have been reported with Ofuran SR use:

Most common (generally mild):

• Nausea
• Headache
• Flatulence
• Diarrhea, dyspepsia, abdominal pain
• Dizziness, drowsiness

Less common but serious (see Precautions and Warnings for full details):

• Pulmonary reactions (acute hypersensitivity-type or chronic fibrotic reactions)
• Hepatotoxicity, including hepatitis and cholestatic jaundice
• Peripheral neuropathy
• Hemolytic anemia (particularly in G6PD-deficient individuals)
• Hypersensitivity reactions including rash, urticaria, and rarely anaphylaxis

Pregnancy: Ofuran SR should be used during pregnancy only if clearly needed and if the potential benefit justifies the potential risk to the fetus; always consult a physician. Ofuran SR is contraindicated at term (38-42 weeks gestation), during labor, and when delivery is imminent, because of the risk of hemolytic anemia in the newborn. Some formal drug references classify Ofuran SR under a legacy pregnancy category B (animal reproduction studies have not demonstrated fetal risk, but adequate well-controlled human studies are lacking); however, some later guidance urges caution regarding use in the first trimester, so use should always be individualized under medical supervision.

Lactation: Ofuran SR passes into breast milk in small (trace) amounts. It should be used with caution during breastfeeding, and avoided if the infant is under one month old, has known or suspected G6PD deficiency, or is otherwise at increased risk of hemolytic anemia. Consult a physician before using Ofuran SR while breastfeeding.

Pulmonary Reactions

Both acute and chronic pulmonary reactions have been reported with Ofuran SR. Acute reactions (fever, chills, cough, chest pain, dyspnea, and infiltrates on chest X-ray) are hypersensitivity-type reactions that usually resolve within days of stopping the drug. Chronic pulmonary reactions, including pulmonary fibrosis, can develop insidiously during prolonged therapy (generally six months or more) and may be irreversible or fatal if unrecognized. Patients on long-term Ofuran SR therapy should be monitored periodically for changes in pulmonary function, and the drug should be discontinued immediately if pulmonary symptoms develop.

Hepatotoxicity

Hepatotoxic reactions, including hepatitis, cholestatic jaundice, and (rarely, with long-term use) chronic active hepatitis and hepatic necrosis, have occurred with Ofuran SR, occasionally with fatal outcomes. Liver function should be monitored during prolonged therapy, and Ofuran SR should be discontinued immediately if signs of hepatic injury occur.

Peripheral Neuropathy

Peripheral neuropathy, which may become severe or irreversible, has been reported with Ofuran SR, particularly with prolonged use and in patients with renal impairment, anemia, diabetes mellitus, electrolyte imbalance, vitamin B deficiency, or debilitation. Patients should report any tingling, numbness, or weakness in the hands or feet promptly.

Renal Function

Ofuran SR requires adequate renal function to concentrate in the urine for antibacterial effect and to avoid systemic toxic accumulation; it is contraindicated in significant renal impairment (see Contraindications).

Hemolytic Anemia / G6PD Deficiency

Hemolytic anemia may occur in patients with glucose-6-phosphate dehydrogenase (G6PD) deficiency; Ofuran SR should be used with caution or avoided in such patients.

Antibiotic Stewardship

Take Ofuran SR exactly as prescribed by your physician; do not stop, extend, skip doses, or share this medicine with others without medical advice, as this may reduce effectiveness and contribute to antibiotic resistance.

Other

Superinfection with resistant organisms, including Clostridioides difficile-associated diarrhea, may occur with any antibiotic including Ofuran SR.

There is no specific antidote for Ofuran SR overdose. Vomiting is the most commonly reported effect of acute overdosage. In case of a suspected overdose of Ofuran SR, seek immediate medical attention or contact a poison control center or emergency services. General supportive measures may be used, including maintaining adequate fluid intake to promote urinary output; Ofuran SR is dialyzable, so hemodialysis may be considered by a physician in severe cases. Do not attempt to manage an overdose at home without professional medical guidance.

Store at room temperature (below 30°C), protected from light and moisture. Keep the container tightly closed and out of the reach and sight of children.

Pediatric Use

Ofuran SR is contraindicated in infants younger than one month of age due to the risk of hemolytic anemia from immature red blood cell enzyme systems. In children one month of age and older, the usual dose is 5-7 mg/kg/day in divided doses (four times daily) for acute infection, or as low as 1 mg/kg/day for long-term suppressive therapy, as directed by a physician. Safety and effectiveness of Ofuran SR in children under 12 years for the dual-release (macrocrystalline/monohydrate) formulation have not been separately established; use the age-appropriate formulation as prescribed.

Use in Elderly

Elderly patients may have age-related reduction in renal function, which can increase the risk of toxicity from Ofuran SR even when serum creatinine appears normal; renal function should be assessed before and periodically during therapy, and Ofuran SR avoided if significant impairment is present (see Contraindications).

Renal Impairment

Ofuran SR is contraindicated in significant renal impairment (see Contraindications and Precautions).

Hepatic Impairment

Ofuran SR should be avoided in patients with a history of cholestatic jaundice or hepatic dysfunction associated with prior Ofuran SR use (see Contraindications).

For acute uncomplicated urinary tract infection, Ofuran SR is typically given for 7 days, or for at least 3 days after urine cultures become sterile, as directed by the prescribing physician. For long-term suppressive (prophylactic) therapy, Ofuran SR may be continued for extended periods at a lower dose under close medical supervision, with periodic reassessment of pulmonary, hepatic, and renal status given the risks of prolonged use.

Nitrofuran antibacterials; urinary anti-infective agents.

Nitrofurantoin is reduced by bacterial flavoproteins into highly reactive intermediate compounds. These intermediates damage bacterial ribosomal proteins and other macromolecules, broadly inhibiting bacterial protein synthesis, aerobic energy metabolism, and DNA/RNA/cell wall synthesis. Because Nitrofurantoin attacks multiple bacterial targets simultaneously rather than one specific pathway, development of acquired bacterial resistance is uncommon.

B

Ofuran SR is contraindicated in infants under one month of age because of the risk of hemolytic anemia related to immature red blood cell enzyme systems. In children one month of age or older, Ofuran SR may be used for treatment of acute uncomplicated urinary tract infections at a dose of 5-7 mg/kg/day in four divided doses, or for long-term suppressive therapy at doses as low as 1 mg/kg/day, under a physician's direction. Safety and efficacy of certain sustained-release formulations of Ofuran SR have not been established in children under 12 years; the appropriate formulation and dose should be selected by the treating physician.