What Is Fosfomycin?

Fosfomycin is an antibiotic medication most commonly used to treat urinary tract infections. It works by inhibiting the ability of bacteria to form proper cell walls, a structure that is critical for their growth and survival. The medication is somewhat unique in the fact that it is not given as a pill, and instead comes in the form of granules that can be dissolved in water. Common side effects of fosfomycin can include nausea, diarrhea, and headache.

The mechanism of action of fosfomycin is to inhibit the ability of bacteria to synthesize their cell walls. Without having a strong outer shell of protection, these cells can perish. Alternatively, the damage to the walls could prevent their ability to successfully reproduce. This medication specifically inhibits a protein known as pyruvyl transferase, and decreases the ability of this protein to help form the cell walls.

Typically, fosfomycin is administered slightly differently in comparison to many other medications. It is sold as a pouch of granules that can be dissolved in water. For certain infections, only a single dose of the medication is required, but for more severe infections the medication might need to be taken every two to three days for one to three weeks. The medication goes by the brand name Monurol®.

Most commonly, fosfomycin is given to treat urinary tract infections. Occasionally, the drug can be used to treat infections of the prostate, but its use in this capacity is not officially approved in the United States. Often in complicated infections, laboratories can test how sensitive the etiologic bacteria is to being killed by a certain antibiotic before giving that specific medication, and fosfomycin is most effective when used in this way. It has proven to be an efficient way to treat infection caused by Enterobacteriaceae, a type of bacteria that is often resistant towards other types of antibiotics.

Common side effects of fosfomycin can include headache, dizziness, nausea, diarrhea, nasal congestion, and a sore throat. Less common side effects can include itchiness, drowsiness, fever, and nervousness. Rarely, it has been associated with hearing loss and liver damage.

In general, fosfomycin can be given to most patients. Patients who previously have had a bad reaction to the medication should avoid taking it in the future. Most doctors and other health care professionals consider the medication to be safe for administration during pregnancy, as it does not cross from the mother’s blood into the developing baby’s circulatory system.