FOSFOMYCIN INJ,LYPHL

Clinical Criteria Summary

Treatment of complicated urinary tract infections (cUTI), including acute pyelonephritis (AP)
Caused by susceptible isolates of Escherichia coli and Klebsiella pneumoniae
Patients 18 years of age and older

6 grams IV every 8 hours over 1 hour for adults with estimated CrCl > 50 mL/min
Duration up to 14 days, guided by severity of infection and clinical status
Dosage adjustment required for estimated CrCl ≤ 50 mL/min per US Prescribing Information
Administer after hemodialysis on hemodialysis days for patients requiring hemodialysis

Assess previous hypersensitivity reactions to oral or parenteral fosfomycin
Recommend a low-sodium diet during treatment due to high sodium load (1,980 mg/vial)

Serum electrolytes (Na, K, Ca, Mg, P)
CBC (monitor for neutropenia)
Fluid status
Estimated CrCl (adjust dosage as needed)
Hepatic enzymes (ALT, AST)
QT prolongation
Evaluate if diarrhea occurs to rule out Clostridioides difficile-associated diarrhea

Known serious hypersensitivity to fosfomycin or any excipients
Avoid in patients with known QT prolongation or ventricular arrhythmias
Avoid co-administration with drugs known to prolong the QT interval (Class IA/III antiarrhythmics, tricyclic antidepressants, macrolides, antipsychotics)
Monitor closely for fluid overload and electrolyte abnormalities in severe hepatic impairment

Positioned as an alternative (not first-line) empiric agent for cUTI
First-line empiric agents include 3rd/4th generation cephalosporins, piperacillin-tazobactam, fluoroquinolones, and carbapenems (if sepsis present)
Reserve novel beta-lactam/beta-lactamase inhibitor combinations and cefiderocol for MDR/carbapenem-resistant pathogens
May be used as an alternative for suspected or confirmed cUTI caused by ESBL-producing Enterobacterales when other agents are not viable due to resistance or contraindications
Particularly appropriate for hemodynamically stable patients who can tolerate the high sodium load
Empiric therapy should be guided by patient-specific factors (history of resistant pathogens, risk of allergic reaction, contraindications, drug-drug interactions)
Therapy should be de-escalated and targeted based on urine culture and susceptibility results