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
Fosfomycin
Phosphonic acid antibiotic (PO granules; IV formulation distinct)
Indication
Acute cystitis β’ ESBL UTI selected β’ MDR infection IV combinations
INDICATIONS (CORE USE)
**Single-dose** uncomplicated cystitis (oral); **IV** MDR regimens specialist β **not interchangeable** products.
ADULT DOSE (STANDARD)
3 g PO single dose cystitis; IV grams multi-dose MDR β **separate pathways**
MAX DOSE
IV protocols grams/day β pharmacy
Route
PO (tromethamine), IV (disodium)
PEDIATRIC DOSE
Oral pediatric data limited β specialist
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 - Oral fosfomycin β IV fosfomycin indication/dose - Resistance emerging β verify local guidance - Do not use oral for pyelonephritis standard
USE IF: Uncomplicated cystitis single dose convenience; ESBL cystitis in some stewardship pathways. AVOID IF: Pyelonephritis standard care; male complicated UTI without ID.
Primary
Secondary
Other
STANDARD (ADULT PO)
3 g PO Γ1 dissolved in water
ADULT DOSE
Oral: one sachet once IV: per MDR gram-negative protocol (grams divided)
PEDIATRIC DOSE
Not routine oral.
MAX DOSE
IV grams/day per protocol
Practical Note
Empty bladder before oral dose.
Clinical warnings
Adverse effects
Pediatrics
Oral pediatric data limited β specialist
Pregnancy
Animal data β human cystitis use when benefit
Lactation
limited data.
Renal impairment
IV adjust CKD; oral single-dose generally avoids accumulation issue. **CrCl scaffold (FMBM β titrate to FDA/SFDA label + institutional pharmacy nomogram):** - **CrCl β₯50** β oral single-dose cystitis per card; **IV MDR** per protocol - **CrCl 10β50** β verify label (oral often acceptable short course); **IV** CrCl-based per protocol - **CrCl <10** β **IV** strong CrCl reduction; oral β verify label / avoid if contraindicated
Hepatic impairment
No adjustment.
Elderly
Renal function for IV pathway.
Dissolve oral granules in water; drink immediately.
Clinical Picture
**Life-threatening (first):** **anaphylaxis** (IV > oral). **Secondary:** GI (oral); IV electrolyte/infusion reactions per program.
Immediate Actions
Stop β antiemetics; IV fluids; anaphylaxis β epinephrine if indicated
Antidote
No specific antidote; treat complications (e.g. anaphylaxis β epinephrine per ACLS)
Decontamination
Usually not required oral
Escalation
Severe anaphylaxis β **ICU**; **IV overdose / severe renal failure β consider hemodialysis** per pharmacy protocol
Common mistakes, resistance logic, and bedside traps
**One and done** cystitis packet. **IV fosfomycin** is a different beast for **MDR ICU** β never confuse.
Stewardship: rotate away from fluoroquinolones. Resistance surveillance needed as use rises. Male UTI β usually investigate, not single-dose oral default. *Stewardship (all antimicrobials):* Empiric choice β syndrome severity + **local antibiogram**; shortest effective course.
Oral tromethamine high urine levels prolonged; IV different PK.
Enolpyruvate transferase inhibitor β early cell wall step.
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