Clinical beta
FMBM is currently in clinical beta. Content is for professional review/testing and must not replace local protocols, senior clinical judgment, or official prescribing references.
Drug Monograph
Nitrofurantoin
Nitrofuran (PO)
Indication
Acute cystitis β’ UTI prophylaxis β’ NOT pyelonephritis
INDICATIONS (CORE USE)
**Uncomplicated cystitis** first-line many guidelines β **avoid CrCl <30** (ineffective + toxicity); **pulmonary/hepatic** toxicity long-term suppressive.
ADULT DOSE (STANDARD)
Macrocrystal 100 mg PO BID Γ 5β7d cystitis; prophylaxis 50β100 mg HS
MAX DOSE
400 mg/day total
Route
PO
PEDIATRIC DOSE
5β7 mg/kg/day divided (max 400 mg/day) β verify formulation
Must-not-miss safety points
Major warning
- **Misuse boundary:** NOT appropriate as sole therapy for **pyelonephritis**, **bacteremia**, or **unstable systemic infection** β escalate route/spectrum when indicated - **MRSA:** **no reliable MRSA coverage** β do not use as monotherapy when MRSA in differential - **CrCl <30** β avoid (ineffective urine levels + toxicity) - **Pulmonary fibrosis** acute/chronic β stop if new dyspnea - **Hepatotoxicity** β LFTs if prolonged - Peripheral neuropathy renal impairment
USE IF: Uncomplicated lower UTI, prophylaxis when indicated. AVOID IF: Pyelonephritis, men, indwelling catheter stones (often inadequate), CrCl <30.
Primary
Secondary
Other
STANDARD (ADULT PO)
100 mg BID Γ 5β7 days cystitis
ADULT DOSE
Macro 100 mg BID; Monohydrate/macrocrystal BID schedules differ slightly by product
PEDIATRIC DOSE
Weight-based divided.
MAX DOSE
400 mg/day
Practical Note
Take with food; complete short course.
Clinical warnings
Adverse effects
Pediatrics
5β7 mg/kg/day divided (max 400 mg/day) β verify formulation
Pregnancy
Avoid near term (hemolysis newborn G6PD); earlier pregnancy per guideline
Lactation
compatible generally.
Renal impairment
CrCl <30 β **avoid**; 30β50 use caution short course only per some labels. **CrCl scaffold (FMBM β titrate to FDA/SFDA label + institutional pharmacy nomogram):** - **CrCl β₯50** β short cystitis courses per indication - **CrCl 10β50** β caution β many labels **avoid if CrCl <30** (urine penetration + toxicity); verify SFDA/FDA - **CrCl <10** β **avoid** (ineffective urine + toxicity risk)
Hepatic impairment
Acute hepatitis on nitro β never rechallenge.
Elderly
Renal function estimate β Cockcroft-Gault matters here.
PO with food; plenty of water.
Clinical Picture
**Life-threatening (first):** **hypoxemic pulmonary** reaction; **acute liver failure**. **Secondary:** neuropathy with renal impairment.
Immediate Actions
Stop β CXR if respiratory symptoms; LFTs if hepatitis
Antidote
No specific antidote; treat complications (e.g. anaphylaxis β epinephrine per ACLS)
Decontamination
Supportive PO
Escalation
Hypoxemic respiratory failure, ALF β **ICU** / transplant referral; **severe renal failure + toxicity β consider HD** (limited role) β supportive
Common mistakes, resistance logic, and bedside traps
**Cystitis champion** β **pyelonephritis pretender**. **CrCl <30 = stop**. **Lungs** can fry on long suppressive.
Stewardship: first-line cystitis where resistance low. Do not use for bacteremia source. Pregnancy: avoid term; OK mid-pregnancy many guidelines. *Stewardship (all antimicrobials):* Empiric choice β syndrome severity + **local antibiogram**; shortest effective course.
Low serum, high urine concentration; short half-life β only lower UTI.
Reduced by bacterial flavoproteins β reactive intermediates damage DNA/ribosomes.
Global data (no country-specific data available)
Saudi Arabia
(placeholder β verify local formulary)
Common trade names are curated examples only β formulations and availability vary. Verify the exact product name with your local pharmacy and national regulator before prescribing or dispensing.
Saudi Arabia
International