📋 Indications & Clinical Dosage
*Acute uncomplicated urinary-tract infections:*
Adult: 50 mg 4 times a day for 3-7 days, to be taken with food
Children 3 months-11 yrs: 750 mcg/kg 4 times a day for 3-7 days; 12-17 years: 50 mg 4 times a day for 3-7 days.
*Severe chronic recurrent urinary-tract infections:*
Adult: 100 mg 4 times a day for 7 days, to be taken with food, reduce dose or discontinue treatment if severe nausea occurs.
Children 12-17 years: 100 mg 4 times a day for 3-7 days.
*Prophylaxis of urinary-tract infection (considered for recurrent infection, significant urinary-tract anomalies, or significant kidney damage):*
Adult: 50-100 mg once daily, dose to be taken at night.
Children 3 months-11 yrs: 1 mg/kg once daily, to be taken at night; 12-17 yrs: 50-100 mg once daily, to be taken at night
*Genito-urinary surgical prophylaxis:*
Adult: 100 mg twice daily on day of procedure and for 3 days afterwards.
⛔ Contraindications
Acute porphyrias, G6PD
Deficiency, infants less than 3 months old
⚠️ Precautions & Warnings
Anaemia, diabetes mellitus, electrolyte imbalance, folate deficiency, pulmonary disease, susceptibility to peripheral neuropathy, urine may be coloured yellow or brown, vitamin B deficiency. Use with caution in hepatic impairment; cholestatic jaundice and chronic active hepatitis reported. Caution in renal impairment; risk of peripheral neuropathy; antibacterial efficacy depends on renal secretion of the drug into urinary tract.
🔄 Drug Interactions
Oral magnesium salts, nalidixic acid, probenecid, sulfinpyrazone.
⚠️ Adverse Reactions / Side Effects
Acute pulmonary reactions, anaphylaxis, angioedema, anorexia, chronic pulmonary reactions (pulmonary fibrosis reported; possible association with lupus erythematosus-like syndrome), diarrhoea, hypersensitivity reactions, nausea, peripheral neuropathy, pruritus, rash, sialadenitis, urticaria, vomiting. Rare: Agranulocytosis, aplastic anaemia, arthralgia, benign intracranial hypertension, blood disorders, cholestatic jaundice, erythema multiforme, exfoliativedermatitis, hepatitis,pancreatitis, thrombocytopenia, transient alopecia
🤰 Pregnancy & Lactation Safety
Pregnancy Risk:
Avoid at term, may produce neonatal
haemolysis.
Lactation / Breastfeeding:
Avoid; small amounts in milk but may be used to produce haemolysis
📚 Official Regulatory & Clinical References
- Drug Regulatory Authority of Pakistan (DRAP): Drug Registration, S.R.O. Price Gazettes & National Essential Medicines List (NEML).
- World Health Organization (WHO): Collaborating Centre for Drug Statistics Methodology (ATC/DDD Index).
- Formulary Standards: British National Formulary (BNF) & Pakistan National Formulary (PNF) guidelines.