Fosfomycin is an antibiotic used to treat cystitis and other bacterial infections. Like the antibiotics nitrofurantoin and ciprofloxacin , it belongs to the group of drugs that can provide relief from bacterial urinary tract infections. Find out everything about taking, effects and side effects of fosfomycin.
What is Fosfomycin?
Fosfomycin is an antibiotic that is classified as a reserve antibiotic because of its wide range of effects. Reserve antibiotics are mainly used for multi-resistant bacteria and life-threatening infections when simple antibiotics are no longer helpful. Fosfomycin can either be injected through the blood vessels or swallowed (orally). The active ingredient is then absorbed through the gastrointestinal tract. For oral use, the active ingredient is in powder or granule form as a compound with trometamol.
Fosfomycin without trometamol is primarily administered intravenously via the blood system. It is used intravenously for severe bacterial infections such as blood poisoning or meningitis . Fosfomycin is well absorbed by the bone tissue and can therefore also be used in bone marrow inflammation or infections with multi-resistant germs.
However, according to a recent risk assessment procedure, the antibiotic should only be used intravenously for severe infections if other antibiotics are not suitable. This is to prevent resistance, which would cause the agent to lose its effectiveness against bacteria.
Was ist Fosfomycin Trometamol?
Fosfomycin trometamol is a salt of fosfomycin. With the help of trometamol, the active substance fosfomycin can be absorbed much better in the gastrointestinal tract. This allows the antibiotic to be taken orally. In this form, fosfomycin is used, for example, to treat uncomplicated urinary tract infections. Fosfomycin is also used in surgical interventions on the urinary tract to prevent bacterial infections.
Is fosfomycin a fluoroquinolone?
Unlike ciprofloxacin, which is also used to treat cystitis, fosfomycin is not a fluoroquinolone. The fluoroquinolones are another class of antibiotics, which, in addition to ciprofloxacin, include active ingredients such as levofloxacin and moxifloxacin . Fluoroquinolones are reserve antibiotics for cystitis, which should be used primarily in complicated urinary tract infections. They are among the broad-spectrum antibiotics and therefore have a very broad spectrum of activity. In addition, there are only a few resistant bacteria to fluoroquinolones. At the same time, broad-spectrum antibiotics also harbor a higher potential for side effects.
Another alternative to fosfomycin, which is also not a fluoroquinoloene, is the antibiotic nitrofurantoin, which is also used for uncomplicated urinary tract infections.
Trade names of Fosfomycin
Several manufacturers sell fosfomycin. That is why it is available under different trade names. For example, the preparations containing fosfomycin have the following names:
- Monuril®
- Fosfomycin Sandoz ®
- Fosfomycin Eberth®
- Fosfomycin AL®
- Fosfomycin Aristo®
How does fosfomycin work?
Fosfomycin is a drug that interferes with the metabolism of the bacterial cell wall. It works by blocking the enzyme pyruvyltransferase. It hinders the construction and maintenance of the bacterial cell wall. Fosfomycin thereby prevents the growth, reproduction and survival of the bacteria.
Is fosfomycin dangerous?
Like other antibiotics, fosfomycin requires a prescription and is only available in pharmacies. Fosfomycin 3 g in oral form is permitted from the age of 12 years and a body weight of 50 kilograms. For people with a lower body weight, for example, Monuril® is available in a pack size of only 2 g.
In general, fosfomycin is well tolerated when taken in accordance with the approval and recommended use. Use outside of the approval can be dangerous due to a lack of experience in this area and should only be done in consultation with the doctor treating you. However, even a single treatment with the antibiotic can cause side effects.
In the case of hypersensitivity to the active substance fosfomycin or one of the accompanying excipients, as well as in the case of a functional disorder of the kidneys ( renal insufficiency ) and in patients on dialysis treatment, the drug should not be given.
Side Effects of Fosfomycin
According to the specialist information, the following side effects can occur when taking fosfomycin:
- Stomach and intestinal problems such as nausea , vomiting, diarrhea , bloating and indigestion and abdominal pain
- headache , dizziness
- fatigue
- Vulvovaginitis (inflammation of the vagina and labia)
- Rashes and dry skin
- Allergic reaction
- itching
- increase in liver values
Interactions of Fosfomycin
While taking fosfomycin, drugs that affect the speed of digestion should not be taken . This includes, for example, metoclopramide, which is used against nausea and nausea.
Taking antibiotics can generally have an impact on the contraceptive effect of oral contraceptives, such as the birth control pill (pill). The intestinal flora often changes during treatment with antibiotics. Among other things, diarrhea can also occur. It is possible that the active ingredients in the pill are only absorbed to a limited extent.
Alcohol should also be avoided during treatment with fosfomycin.
How and when to take fosfomycin?
Fosfomycin is usually taken in a single dose of 3,000 mg (3 g) as a soluble powder or granules . It unfolds its effect in the bladder.
It is recommended to take it in the evening, ideally after the last urination before going to sleep, since urine is most concentrated at night. In addition, there should be a gap of at least two to three hours between your last meal and your last meal.
Fosfomycin is usually used in the single dose described. Alternatively, it can also be taken over three days in lower doses.
Fosfomycin is also a reserve and broad spectrum antibiotic. It is therefore given intravenously via the blood system in severe infections .
How long is fosfomycin in the body and how long does fosfomycin have to stay in the bladder?
About two to four hours after taking fosfomycin, there should be enough drug in the urine to inhibit the growth of bacteria. A sufficiently high concentration of fosfomycin is usually still present in the bladder 36 to 48 hours after ingestion.
Since the active ingredient continuously passes into the bladder via the blood, going to the toilet does not have to be avoided even shortly after ingestion, but is actually beneficial to healing.
How long does it take for fosfomycin to work and when does it get better?
When and how quickly fosfomycin works cannot be answered uniformly. The effect of fosfomycin usually sets in relatively quickly after taking the drug. Fosfomycin inhibits the growth of bacteria and kills them. Therefore, the symptoms of cystitis should improve within a few days after ingestion.
Nevertheless, the course of the disease and the severity of a urinary tract infection are very individual. For example, a bladder infection can be significantly better for some sufferers the day after taking it, while for others the symptoms persist for days. In addition to taking the antibiotic, it is important to ensure that you drink enough water.
However, fosfomycin can only work if the pathogens are sensitive to the active substance and as long as there is sufficient active substance in the blood and bladder.
pregnancy and breast feeding period
Fosfomycin crosses the placenta. This means that the active substance can reach the unborn child in relevant quantities via the placental barrier. So far, there has been little experience or studies on the side effects of fosfomycin in pregnant and breastfeeding women. Therefore, the use of the drug is not recommended during pregnancy and breastfeeding. Fosfomycin is therefore only an antibiotic of second choice during pregnancy. In the event of a urinary tract infection during pregnancy, you should always consult your doctor.
