Fosfomycin

General

• Type: Antibiotic
• Dosage Forms: oral
• Common Trade Names: Monurol

Adult Dosing

• Uncomplicated UTI: 3g PO x 1

Pediatric Dosing

• >12 y/o: 3 g PO x 1

Special Populations

• Pregnancy Rating: B
• Lactation Risk: Infant risk cannot be ruled out
• Renal Dosing: Half life increased in renal impairment, no specific adjustment
• Hepatic dosing: no adjustment

Contraindications

• Allergy to class/drug
• Caution if hepatic impairment
• Caution if recent antibiotic-associated colitis

Adverse Reactions

Serious

• Angioedema
• Aplastic Anemia
• Asthma Exacerbation
• Hepatic Necrosis
• Toxic Megacolon
• C. difficile diarrhea

Common

• Diarrhea
• Vaginitis
• Rhinitis
• nausea
• headache
• dizziness
• back pain
• abdominal pain
• dysmenorrhea

Pharmacology

• Half-life: 5.7 hours
• Metabolism:
• Excretion: Urine 38%, Feces 18%
• Mechanism of Action: Bactericidal, inhibits cell wall synthesis

Antibiotic Sensitivities

Group	Organism	Sensitivity
Gram Positive	Strep. Group A, B, C, G	X1
	Strep. Pneumoniae	S
	Viridans strep	X1
	Strep. anginosus gp	X1
	Enterococcus faecalis	S
	Enterococcus faecium	I
	MSSA	S
	MRSA	S
	CA-MRSA	S
	Staph. Epidermidis	X1
	C. jeikeium	X1
	L. monocytogenes	R
Gram Negatives	N. gonorrhoeae	X1
	N. meningitidis	X1
	Moraxella catarrhalis	X1
	H. influenzae	X1
	E. coli	S
	Klebsiella sp	S
	E. coli/Klebsiella ESBL+	S
	E coli/Klebsiella KPC+	S
	Enterobacter sp, AmpC neg	S
	Enterobacter sp, AmpC pos	S
	Serratia sp	X1
	Serratia marcescens	S
	Salmonella sp	S
	Shigella sp	X1
	Proteus mirabilis	X1
	Proteus vulgaris	S
	Providencia sp.	X1
	Morganella sp.	X1
	Citrobacter freundii	X1
	Citrobacter diversus	X1
	Citrobacter sp.	X1
	Aeromonas sp	X1
	Acinetobacter sp.	R
	Pseudomonas aeruginosa	R
	Burkholderia cepacia	X1
	Stenotrophomonas maltophilia	X1
	Yersinia enterocolitica	X1
	Francisella tularensis	X1
	Brucella sp.	X1
	Legionella sp.	X1
	Pasteurella multocida	X1
	Haemophilus ducreyi	X1
	Vibrio vulnificus	X1
Misc	Chlamydophila sp	X1
	Mycoplasm pneumoniae	X1
	Rickettsia sp	X1
	Mycobacterium avium	X1
Anaerobes	Actinomyces	X1
	Bacteroides fragilis	X1
	Prevotella melaninogenica	X1
	Clostridium difficile	X1
	Clostridium (not difficile)	X1
	Fusobacterium necrophorum	X1
	Peptostreptococcus sp.	X1

Key

• S susceptible/sensitive (usually)
• I intermediate (variably susceptible/resistant)
• R resistant (or not effective clinically)
• S+ synergistic with cell wall antibiotics
• U sensitive for UTI only (non systemic infection)
• X1 no data
• X2 active in vitro, but not used clinically
• X3 active in vitro, but not clinically effective for Group A strep pharyngitis or infections due to E. faecalis
• X4 active in vitro, but not clinically effective for strep pneumonia

Source

• Epocrates 12/7/14

Authors

Ross Donaldson, Ben Isakson, Claire, Neil Young, Daniel Ostermayer