Furadantin contains nitrofurantoin as its active component. It belongs to the antibiotics class and is specifically used to treat infections of the urinary tract. The medication is supplied as a pill in two strengths: 50 mg and 100 mg. In Hong Kong, Furadantin is a prescription-only drug regulated by the Hong Kong Department of Health.
Nitrofurantoin is absorbed from the gastrointestinal tract and is rapidly excreted unchanged in the urine, where it reaches concentrations high enough to inhibit bacterial growth. It works by:
Because the drug is eliminated mainly via the kidneys, its therapeutic effect is localized to the urinary tract, limiting systemic exposure.
In Hong Kong, the approved indications for nitrofurantoin (Furadantin) are limited to uncomplicated urinary tract infections (UTIs) caused by susceptible bacteria. Typical patient populations include adult women with acute cystitis and, in some cases, men with uncomplicated infections when culture data support its use.
No robust, peer-reviewed evidence supports off-label uses of Furadantin. Consequently, this section is omitted.
Absolute contraindications
Relative contraindications
Special populations
If any of these conditions apply, discuss alternatives with a healthcare professional.
These effects are usually transient and often improve with food intake.
Patients should disclose all concurrent medications, supplements, and herbal products to their prescriber.
Standard dosing for uncomplicated UTIs
50 mg tablet: 4 times daily (every 6 hours) or
100 mg tablet: 2 times daily (every 12 hours).
Duration is typically 5-7 days, but the prescriber may adjust based on infection severity and response.
Administration tips
Swallow tablets whole with a full glass of water.
Taking the dose with food or milk can lessen stomach upset.
Do not crush or chew the tablets, as this may alter absorption.
Missed dose
Take the missed dose as soon as you remember unless it is near the time of the next scheduled dose.
Do not double the dose to make up for a missed one.
Overdose
Symptoms may include nausea, vomiting, abdominal pain, and dizziness.
Seek immediate medical assistance; treatment is supportive and may involve activated charcoal.
Discontinuation
For short courses, abrupt cessation is acceptable.
For prolonged therapy, tapering is not required but renal function should be reassessed before stopping.
Regular follow-up with a healthcare provider ensures efficacy and early detection of adverse effects.
This article provides educational information about Furadantin and is not a substitute for professional medical advice. Treatment decisions, including use for unapproved indications, must be made under the guidance of a qualified healthcare provider. The content is intended for informational purposes and does not constitute medical recommendations. Always consult a physician before starting, stopping, or changing any medication regimen.
Mild to moderate renal impairment (creatinine clearance ≥ 60 mL/min) may still allow use, but the prescriber should assess kidney function and possibly adjust the dose. Severe impairment (CrCl < 60 mL/min) is a contraindication because therapeutic urine concentrations cannot be achieved.
No specific dairy restriction exists, but taking the tablet with food or milk can improve gastrointestinal tolerance and may modestly enhance absorption.
Patients often notice symptom improvement within 48 hours, though full bacterial eradication may take the complete prescribed course (typically 5-7 days).
Nitrofurantoin can be prescribed to men when the infecting organism is susceptible, but clinicians usually prefer agents that achieve higher prostate concentrations for male patients.
A mild rash may be a common allergic reaction; discontinue the medication and contact a healthcare professional promptly, as more severe hypersensitivity reactions can occur.
Yes. Antacids containing magnesium or aluminum can reduce nitrofurantoin absorption. Separate dosing by at least two hours to maintain effectiveness.
Nitrofurantoin is generally avoided in the third trimester (≥ 38 weeks) due to neonatal risks. First-trimester use should be discussed with a prescriber, weighing potential benefits against risks.
Keep them in the original container at room temperature, away from moisture and heat, and out of reach of children. Do not use tablets past their expiration date.
Chronic therapy (typically > 6 months) has been associated with pulmonary toxicity. Regular monitoring for respiratory symptoms is recommended during extended use.
No. Furadantin is a prescription-only medication in Hong Kong, and any purchase must be made through a licensed pharmacy with a valid prescription from a qualified healthcare professional.
