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Fosfomycin

By

Brian J. Werth

, PharmD, University of Washington School of Pharmacy

Last full review/revision May 2020
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Fosfomycin is a novel class of antibacterial drugs Overview of Antibacterial Drugs Antibacterial drugs are derived from bacteria or molds or are synthesized de novo. Technically, “antibiotic” refers only to antimicrobials derived from bacteria or molds but is often (including... read more with a chemical structure unrelated to other known antibiotics. It is a bactericidal drug that disrupts cell wall synthesis by inhibiting phosphoenolpyruvate synthetase and thus interferes with the production of peptidoglycan.

In the US, it is available only as a powder formulation of fosfomycin tromethamine, which can be dissolved in liquid and taken orally. Outside the US, IV formulations are available.

Pharmacokinetics

Fosfomycin does not bind to plasma proteins and distributes widely into tissues. Fosfomycin is excreted in urine mainly by glomerular filtration without biotransformation. After oral dosing, urinary levels exceed the MICs of susceptible pathogens for over 24 hours.

An IV formulation of fosfomycin is available in some countries and can be useful for more serious infections, including central nervous system infections, osteomyelitis, and pneumonia; when used to treat these infections, it is often used with other antibiotics such as beta-lactams.

Indications for Fosfomycin

Fosfomycin has a broad spectrum of activity against both gram-positive and gram-negative organisms, including many antibiotic-resistant organisms such as

Oral fosfomycin should be used only for uncomplicated (ie, lower) urinary tract infections caused by susceptible pathogens. However, because it has a broad spectrum of activity, IV fosfomycin is sometimes used to treat infections with multidrug-resistant organisms at other anatomic sites.

Contraindications to Fosfomycin

There are no significant contraindications to its use other than known hypersensitivity to fosfomycin or to any component of the formulation.

Use During Pregnancy and Breastfeeding

Fosfomycin crosses the placenta but is generally considered to be safe for treatment of cystitis in pregnant women.

How much fosfomycin enters breast milk is unknown, and caution is advised if treatment with fosfomycin is necessary for breastfeeding women.

Adverse Effects of Fosfomycin

Fosfomycin is generally well-tolerated and has a low rate of adverse effects, which include mainly gastrointestinal symptoms (eg, nausea, diarrhea).

Dosing Considerations for Fosfomycin

For uncomplicated urinary tract infections in women, a single oral dose of fosfomycin tromethamine 5.61 g (equivalent to 3 g of fosfomycin) dissolved in liquid is used. A longer treatment course is probably necessary for infections at other sites (eg, prostate [1 Dosing considerations reference Fosfomycin is a novel class of antibacterial drugs with a chemical structure unrelated to other known antibiotics. It is a bactericidal drug that disrupts cell wall synthesis by inhibiting phosphoenolpyruvate... read more ]).

Dosing considerations reference

Drugs Mentioned In This Article

Drug Name Select Trade
No US brand name
CLEOCIN
CUBICIN
FLAGYL
MONUROL
ZYVOX
VIBATIV
DALVANCE
SIVEXTRO
ORBACTIV
BACTROBAN
AZACTAM
VANCOCIN
TINDAMAX
FORTAZ, TAZICEF
ZITHROMAX
BIAXIN
ERY-TAB, ERYTHROCIN
DIFICID
No US brand name
No US brand name
GENOPTIC
ANCEF, KEFZOL
FURADANTIN, MACROBID, MACRODANTIN
KEFLEX
THAM
No US brand name
CEFOTAN
MEFOXIN
No US brand name
CEFTIN, ZINACEF
No US brand name
No US brand name
SUPRAX
CLAFORAN
No US brand name
No US brand name
No US brand name
MAXIPIME
No US brand name
BACIIM
TYGACIL
ACHROMYCIN V
MINOCIN
BICILLIN L-A
No US brand name
PRIMSOL
MYCOBUTIN
VIBRAMYCIN
XERAVA
RIFADIN, RIMACTANE
No US brand name
PRIFTIN
XIFAXAN
DORIBAX
INVANZ
MERREM
AMOXIL
SULFAMYLON
No US brand name
BLEPH-10
No US brand name
NALLPEN IN PLASTIC CONTAINER
BACTOCILL IN PLASTIC CONTAINER
AZULFIDINE
BACTRIM, SEPTRA
DARAPRIM
SILVADENE
QUALAQUIN
CILOXAN, CIPRO
No US brand name
ZEMDRI
No US brand name
TOBI, TOBREX
No US brand name
NUZYRA
No US brand name
COLY-MYCIN M
ARALEN
PROGRAF
TIKOSYN
SEROQUEL
LANOXIN
OZURDEX
DILANTIN
LANIAZID
No US brand name
NARDIL
MARPLAN
DEMEROL
WELLBUTRIN, ZYBAN
No US brand name
SYNERCID
PROZAC, SARAFEM
ELIXOPHYLLIN
ANTABUSE
COUMADIN
ACZONE
No US brand name
No US brand name
OCUFLOX
AFRINOL, SUDAFED
ADRENALIN
LEVOPHED
BAXDELA
FACTIVE
LEVAQUIN
AVELOX
No US brand name
No US brand name
ZYMAR
No US brand name
ORAP
ZOSYN
CORTEF, SOLU-CORTEF
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