How amphotericin B works
The antifungal agent amphotericin B causes pores in the membrane of fungal cells. Minerals such as potassium and sodium can pass freely through these pores, derailing the strictly regulated mineral balance of the fungal cell – it perishes.
The cell membrane of living organisms consists mainly of lipids. In addition, substances are stored that keep the membrane mobile and flexible so that the cell can function optimally. In animal (and thus also human) cells, this substance is cholesterol, whereas in fungal cells it is a chemically similar compound called ergosterol. Amphotericin B attaches itself specifically to ergosterol, forming a pore in the fungal cell membrane.
Absorption, degradation and excretion
Amphotericin B is hardly absorbed into the blood when administered locally on the oral mucosa and when taken by mouth.
When is amphotericin B used?
Amphotericin B is approved for the treatment of:
- yeast infections of the oral mucosa, gastrointestinal tract, and vaginal mucosa
- @ severe systemic (affecting the whole body) fungal infections
Fungal infections of internal organs often occur in immunocompromised patients such as those infected with HIV or those with a donor organ.
Treatment is given until the infection is safely cured.
The World Health Organization (WHO) also recommends amphotericin for the treatment of certain parasitic infections such as leishmaniasis, trichomonad and trypanosome infections.
How Amphotericin B is used
For local treatment of the oral cavity, ten to one hundred milligrams of amphotericin B are sucked as a lozenge or spread as a suspension in the oral cavity four times a day after meals and before bedtime.
For intravenous treatment in the hospital, the dose can be increased many times over under medical observation. The duration of treatment is usually about two weeks, but sometimes longer.
What are the side effects of amphotericin B?
When taken as a mucosal therapeutic agent, the active substance hardly passes into the blood, which is why the treatment is usually well tolerated. The most common side effects are nausea, vomiting, diarrhea, rash and itching.
When amphotericin B is administered intravenously, the side effect rate is much higher. More than ten percent of those treated develop low potassium levels, high creatinine levels, labored breathing, nausea and vomiting, a change in kidney function, low blood pressure, chills, and fever.
One in ten to one hundred patients may also develop anemia, skin rashes, low blood magnesium levels, and poor liver function.
What should be considered when using amphotericin B?
Contraindications
Amphotericin B is contraindicated in:
- hypersensitivity to the active substance or to any of the other components of the drug
- severe liver and kidney dysfunction (applies only to intravenous preparations)
Drug interactions
When using amphotericin B against fungal infections of the oral mucosa or gastrointestinal tract, there are no known interactions with other active substances.
However, during intravenous therapy with amphotericin B, interactions with other active ingredients may occur. For example, dehydrating agents (diuretics such as hydrochlorothiazide and furosemide) and agents that damage the kidneys, such as anticancer drugs (e.g., flucytosine, cisplatin), antibiotics (such as gentamycin), and immune system-suppressing agents (such as ciclosporin), can cause increased damage to the kidneys when combined with amphotericin B.
Age restriction
Amphotericin B can also be used in infants and children. The dosage is adjusted to the body weight of the small patient.
Pregnancy and lactation
Only limited data are available on therapy with amphotericin B during pregnancy and lactation. Therefore, use in pregnant and lactating women should only be undertaken after a careful risk-benefit assessment.
According to experts, local or oral therapy does not require restriction of breastfeeding. If systemic application is necessary during the breastfeeding period, breastfeeding is also allowed.
How to obtain medicines containing amphotericin B
Preparations containing the active ingredient amphotericin B are available on prescription in Germany, Austria and Switzerland in all dosage forms and doses.
Since when is amphotericin B known?
Amphotericin A, which is also contained in the product, has hardly any fungicidal effect. By contrast, the active ingredient amphotericin B can now be used to successfully treat almost all fungal infections.
