Fosfomycin
Mechanism :
As a phosphonic acid derivative, fosfomycin inhibits bacterial wall synthesis (bactericidal) by inactivating the enzyme, pyruvyl transferase, which is critical in the synthesis of cell walls by bacteria.
Indication :
- Acute cystitis
- Multidrug resistant gram-negative and gram-positive pathogens (Fosfomycin is not active against anaerobes, such as Bacteroides spp.). Pseudomonas spp., Acinetobacter spp., Stenotrophomonas maltophilia, Burkholderia cepacia, Staphylococcus capitis, Staphylococcus saprophyticus, Mycobacterium tuberculosis, Morganella morganii are intrinsically resistant to fosfomycin.
Contraindications :
Hypersensitivity to fosfomycin or any component of the formulation.
Dosing :
Safety & efficacy not established in children.
Acute cystitis:
>12 years:
3 g PO once.
<12 years:
1-2 g PO once.
Complicated urinary tract infections (complicated cystitis):
3 g fosfomycin every 2 to 3 days for a total of 3 doses PO.
Recurrent UTI:
IV:
100-200 mg/kg/day for 7-10 days plus
amikacin at 15 mg/kg/day for 5 days or
ceftazidime at 100-150 mg/kg/day for 7-10 days.
Adverse Effect :
Headache, pain, dizziness, skin rash, diarrhea, nausea, abdominal pain, dyspepsia, vaginitis, dysmenorrhea, back pain, weakness.
Interaction :
Lactobacillus and Estriol: Antibiotics may diminish the therapeutic effect of Lactobacillus and Estriol.
Sodium Picosulfate: Antibiotics may diminish the therapeutic effect of Sodium Picosulfate. Management: Consider using an alternative product for bowel cleansing prior to a colonoscopy in patients who have recently used or are concurrently using an antibiotic.
Cholera Vaccine: Antibiotics may diminish the therapeutic effect of Cholera Vaccine.
Hepatic Dose :
No dosage adjustments are needed.