Infectofos (Fosfomycin)

• Fosfomycin is used to treat bacterial infections affecting specific organ systems.
• Complicated urinary tract infections: effective in eradicating Gram‑negative and Gram‑positive pathogens causing upper and lower urinary tract involvement.
• Lower respiratory tract infections: used to manage bacterial pneumonia and bronchitis when susceptible organisms are identified.
• Skin and soft tissue infections: employed for cellulitis, wound infections and other soft‑tissue bacterial conditions.

• Fosfomycin exerts its antibacterial activity by inhibiting the MurA enzyme (enolpyruvyl transferase), a key catalyst in the early stage of peptidoglycan synthesis. By blocking the formation of N‑acetylmuramic acid, the drug prevents bacterial cell wall construction, leading to cell lysis and death of susceptible organisms.

Fosfomycin may be associated with a range of adverse reactions, varying from mild to severe.

Common Side Effects

• Nausea: mild gastrointestinal upset that often resolves without intervention.
• Diarrhea: loose stools occurring during therapy.
• Headache: transient cranial discomfort.
• Injection site reactions: erythema, pain or swelling at the intravenous site.

Serious or Rare Side Effects

• Hypersensitivity reactions: rash, pruritus, or anaphylaxis requiring immediate medical attention.
• Hepatotoxicity: elevated liver enzymes or jaundice in rare cases.
• Hematologic abnormalities: neutropenia or thrombocytopenia reported infrequently.

When prescribing fosfomycin, clinicians should consider several precautionary measures to ensure safe use.

• Renal function: adjust therapy in patients with severe renal impairment.
• Pregnancy: use only if potential benefit outweighs risk, as safety data are limited.
• Concomitant nephrotoxic drugs: monitor for additive kidney toxicity.
• Electrolyte balance: observe serum potassium and magnesium during prolonged therapy.
• Allergies: avoid in individuals with known hypersensitivity to fosfomycin or related compounds.
• Store at ambient temperature: keep vials in original packaging, protect from light and moisture, and do not freeze.

Fosfomycin can interact with other medicines, altering its efficacy or safety profile.

Major Interactions (Avoid)

• Anticoagulants (e.g., warfarin): may increase INR, requiring close monitoring.
• Live vaccines: concurrent use may reduce vaccine efficacy.

Moderate Interactions (Monitor Closely)

• Aminoglycosides: combined nephrotoxicity risk; monitor renal function.
• Loop diuretics: may enhance electrolyte disturbances.
• Probenecid: can increase fosfomycin plasma concentrations.
• Oral contraceptives: potential reduction in effectiveness; advise additional contraceptive measures.