fosfomycin tromethamine
Monurol

Available forms
Available by prescription only
Single-dose sachet: 3 g

Indications and dosages
 Uncomplicated urinary tract infections (acute cystitis) in women caused by susceptible strains of Escherichia coli and Enterococcus faecalis. Women older than age 18: 1 sachet P.O. mixed with 3 to 4 oz (1/2 cup) of cold water just before ingestion.

Pharmacodynamics
Bactericidal action: Inhibits bacterial cell wall synthesis. It’s effective in the urinary tract because it reduces adherence of bacteria to uroepithelial cells.

Pharmacokinetics
Absorption: Rapidly absorbed following oral administration and converted to free acid, fosfomycin. When drug is taken on empty stomach, levels peak within 2 hours; within 4 hours when taken with food.
Distribution: Mean apparent steady state volume of distribution is 136 L following oral administration. Not bound to plasma proteins; distributed to kidneys, bladder wall, prostate, and seminal vesicles. Crosses placental barrier.
Metabolism: Not reported.
Excretion: Excreted unchanged in both urine and feces.

Contraindications and precautions
Contraindicated in patients hypersensitive to drug. Use cautiously in patients with renal impairment.

Interactions
Drug-drug. Metoclopramide: Lowers serum level and urinary excretion of fosfomycin. Avoid use together.
Other drugs that increase GI motility: May increase GI effects. Monitor patient.

Adverse reactions
CNS: asthenia, dizziness, headache.
EENT: pharyngitis, rhinitis.
GI: abdominal pain, diarrhea, dyspepsia, nausea.
GU: dysmenorrhea, vaginitis.
Musculoskeletal: back pain.
Skin: rash.

Effects on lab test results
• May increase bilirubin, ALT, AST, and alkaline phosphatase levels.
• May increase eosinophil count. May decrease hemoglobin and hematocrit. May increase or decrease WBC and platelet counts.

Overdose and treatment
No cases of overdose have been reported. If overdose occurs, provide supportive and symptomatic treatment.

Special considerations
• Using more than one single-dose sachet to treat a single episode of acute cystitis won’t improve success and may cause adverse reactions.
• Obtain urine specimens for culture and sensitivity before therapy and after completion.
Breast-feeding patients
• It isn’t known whether drug appears in breast milk. Because many drugs do, a decision should be made to stop either breast-feeding or drug.
Pediatric patients
• Safety and effectiveness in children age 12 and younger haven’t been established in well-controlled studies.
Geriatric patients
• There are no significant differences in drug effectiveness or safety in women age 65 and younger compared with those older than age 65.

Patient education
• Show patient how to properly take drug. The entire contents of a single-dose sachet should be mixed with 3 to 4 oz (1/2 cup [120 ml]) cold water, stirred to dissolve, and drunk immediately.
• Tell patient to call if symptoms don’t improve in 2 to 3 days.
• Inform patient that drug may be taken without regard to food.

Reactions may be common, uncommon, life-threatening, or COMMON AND LIFE THREATENING.
◆ Canada only
◇ Unlabeled clinical use