Fosfomycin

Pronunciation

(fos foe MYE sin)


U.S. Brand Names

Monurol™



Synonyms

Fosfomycin Tromethamine



Generic Available

No



Canadian Brand Names

Monurol™



Use

Single oral dose in the treatment of uncomplicated urinary tract infections in women due to susceptible strains of and ; may have an advantage over other agents since it maintains high concentration in the urine for up to 48 hours

E. coliEnterococcus

Use - Unlabeled/Investigational

Multiple doses have been investigated for complicated urinary tract infections in men



Pregnancy Risk Factor

B



Lactation

Enters breast milk/not recommended



Adverse Reactions

1% to 10%:

Central nervous system: Headache (47%), dizziness (1%)

Dermatologic: Rash (1%)

Gastrointestinal: Diarrhea (2% to 10%), nausea (4%), epigastric discomfort (1%), abdominal pain

Genitourinary: Vaginitis

Neuromuscular & skeletal: Weakness (1%)

<1%: Anorexia, drowsiness, fatigue, paresthesia, pruritus, somnolence, vomiting

Postmarketing and/or case reports: Angioedema, aplastic anemia, cholestasis, hepatic necrosis, jaundice, optic neuritis, toxic megacolon

Overdosage/Toxicology

Symptomatic and supportive treatment is recommended in the event of an overdose.



Drug Interactions

Antacids or calcium salts may cause precipitate formation and decrease fosfomycin absorption

Metoclopramide: Increased gastrointestinal motility may lower fosfomycin tromethamine serum concentrations and urinary excretion. This drug interaction possibly could be extrapolated to other medications which increase gastrointestinal motility.

Stability

Store at 15°C to 30°C (59°F to 86°F)



Mechanism of Action

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; the tromethamine salt is preferable to the calcium salt due to its superior absorption



Pharmacodynamics/Kinetics

Absorption: Well absorbed

Distribution: Vd: 2 L/kg; high concentrations in urine; well into other tissues; crosses maximally into CSF with inflamed meninges

Protein binding: <3%

Bioavailability: 34% to 58%

Half-life elimination: 4-8 hours; Clcr<10 mL/minute: 50 hours

Time to peak, serum: 2 hours

Excretion: Urine (as unchanged drug); high urinary levels (100 mcg/mL) persist for >48 hours

Dosage

Adults: Oral:

Female: Uncomplicated UTI: Single dose of 3 g in 4 oz of water

Male:

Complicated UTI (unlabeled): 3 g every 2-3 days for 3 doses

Prostatitis (unlabeled): 3 g every 3 days for a total of 21 days

Dosing adjustment in renal impairment: Decrease dose; 80% removed by dialysis, repeat dose after dialysis

Dosing adjustment in hepatic impairment: No dosage decrease needed

Administration

Always mix with water before ingesting; do not administer in its dry form; pour contents of envelope into 90-120 mL of water (not hot), stir to dissolve and take immediately



Monitoring Parameters

Signs and symptoms of urinary tract infection; urine culture plus sensitivity



Patient Education

May be taken with or without food; avoid use of antacids or calcium salts within 4 hours before or 2 hours after taking fosfomycin; contact your prescriber if signs of allergy develop; if symptoms do not improve after 2-3 days, contact your prescriber



Additional Information

Many gram-positive and gram-negative organisms such as staphylococci, pneumococci, , , , , spp, and some strains of , indole-negative , and are inhibited. , and anaerobic gram-negative cocci are resistant.

E. coliSalmonellaShigellaH. influenzaeNeisseriaP. aeruginosaProteusProvidenciaB. fragilis

Dental Health: Effects on Dental Treatment

No significant effects or complications reported



Dental Health: Vasoconstrictor/Local Anesthetic Precautions

No information available to require special precautions



Mental Health: Effects on Mental Status

May cause drowsiness



Mental Health: Effects on Psychiatric Treatment

None reported



Dosage Forms

Powder, as tromethamine: 3 g



References

Patel SS, Balfour JA, and Bryson HM, "Fosfomycin Tromethamine. A Review of Its Antibacterial Activity, Pharmacokinetic Properties, and Therapeutic Efficacy as a Single-Dose Oral Treatment for Acute Uncomplicated Lower Urinary Tract Infections,"Drugs, 1997, 53(4):637-56.

Shrestha N, Amuh D, Goldman MP, et al, "Treatment of a Complicated Vancomycin-Resistant Enterococcal Urinary Tract Infection With Fosfomycin,"Infectious Diseases in Clinical Practice, 2000, 9:368-71.

International Brand Names

Afos® (RO); Faremicin® (IT); Fosfocil® (DO, GT, HN, MX, PA, SV); Fosfocil® [inj.] (DO, GT, HN, MX, PA, SV); Fosfocina® [caps./liqu.oral] (ES); Fosfocina® (EC); Fosfocina® [inj.] (ES); Fosfocine® (FR); Fosfocin® [inj.] (IT); Fosfocin® (IT); Fosfomycin Biochemie® (AT); Fosmicin® (ID, TH); Fosmicin-S® (JP); Francital® (IT); Infectofos® (DE); Ipamicina® (IT); Monural® (HU, RO, RU, YU); Monuril® (AT, BE, BR, CH, CO, DE, FR, GB, IT, LU, NL, PT); Monurol® (AR); Monurol™ (CA); Monurol® (CL, ES, FI, IL, MX); Solufos® [caps./liqu.oral] (ES); Solufos® [inj.] (ES); Ultramicina® (IT); Uniryle® (RO); Uridoz® (FR); Urizone® (ZA); Veramina® (AR)



Review Date: 1969-12-31 Reviewed By: Keywords: ,
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