How fosfomycin works
Fosfomycin acts bactericidal (kills bacteria) by inhibiting the first step in the synthesis of the bacterial cell wall: it prevents the formation of N-acetylmuramic acid, which is essential for building the bacterial cell wall. Without an intact cell wall, the bacterium cannot survive – it dies.
The broad-spectrum antibiotic is effective against many different bacteria, such as staphylococci, streptococci, pneumococci as well as enterococci.
There is a risk that bacteria can develop resistance to fosfomycin due to altered transport mechanisms or certain proteins. Therefore, it is often administered in combination with other antibiotics in severe infections.
Absorption, degradation and excretion
The drug is administered either by mouth (orally) or directly into the bloodstream as an infusion. When administered orally, only a portion of the antibiotic is absorbed into the body. It is not metabolized and is mainly excreted in the urine.
The time after which half of fosfomycin is excreted again (half-life) is about two hours on average.
When is fosfomycin used?
- Infections of the central nervous system (CNS) such as meningitis (meningitis)
- Infections of the skin and soft tissues
- Pneumonia and lung abscess
- Inflammation of the inner lining of the heart (endocarditis)
In such cases, it is usually used in combination with another antibiotic.
In uncomplicated urinary tract infections (without complicating factors such as high fever, flank pain, concomitant diseases, etc.), oral fosfomycin (as fosfomycin-trometamol) is the drug of first choice.
How fosfomycin is used
The intravenous dosage of the antibiotic is determined by the treating physician. It depends, among other things, on the type and severity of the infection and the age of the patient. In the case of impaired kidney function, the dose must be reduced.
The antibiotic can be administered as an infusion to newborns. The dose is calculated individually depending on body weight.
Oral fosfomycin is administered in a dosage of 3 grams as a single dose. For this purpose, the powder is stirred into a glass of water and taken on an empty stomach, i.e. two to three hours before or after a meal, preferably shortly before bedtime.
What are the side effects of fosfomycin?
The antibiotic may cause several side effects, including:
- Gastrointestinal symptoms such as nausea, vomiting, diarrhea
- @ headache
- allergic skin reactions
If you suffer from severe side effects or symptoms not mentioned above, please consult a doctor.
What should be considered when using Fosfomycin?
Contraindications
Fosfomycin should not be used if the patient is allergic to the active substance or suffers from acute renal failure.
Interactions
Fosfomycin may interact with other drugs taken at the same time. For example, metoclopramide (anti-nausea and anti-vomiting medication) taken at the same time may interfere with the absorption of the antibiotic into the body. Other drugs that also stimulate the movement of the intestines may have a similar effect.
In addition, the effectiveness of the antibiotic is reduced if it is taken together with a meal. Therefore, a time interval is recommended.
Age restriction
Pregnancy and lactation
To date, there is no evidence (including from animal studies) that fosfomycin increases the risk of malformations (teratogenic risk) in the unborn child. Nevertheless, in pregnancy should be switched to better studied antibiotics such as pivmecillinam or penicillins.
During breastfeeding, only a small amount of the active substance passes into breast milk. After single oral administration, breastfeeding can be unrestricted.
How to obtain medicines containing fosfomycin
Fosfomycin is available by prescription in Germany, Austria, and Switzerland in all dosage forms and doses. Currently, no intravenous preparations are registered in Austria and Switzerland, but they can be obtained if needed.