Amfoteritsiin

Amfoteritsiin, known in English as amphotericin B, is a polyene macrolide antifungal agent produced by the bacterium Streptomyces nodosus. It has a broad spectrum of activity against many systemic fungal pathogens and is used for life-threatening infections where other treatments are unsuitable or ineffective. It remains a key option for certain conditions such as cryptococcal meningitis, mucormycosis, and invasive aspergillosis in specific settings, and is sometimes given in combination with other antifungals like flucytosine.

Mechanism of action is based on binding to ergosterol, a key component of fungal cell membranes. This binding creates pores that disrupt membrane integrity, causing leakage of essential ions and molecules and ultimately fungal cell death. The drug has higher affinity for ergosterol than for cholesterol in human cells, which underpins its selective toxicity, although toxicity is still a major limitation.

Amfoteritsiin is not orally active and is administered intravenously. It has limited penetration into the central nervous system unless meningitis or meningeal inflammation is present. Pharmacokinetics vary by formulation; conventional amphotericin B deoxycholate is more nephrotoxic, while lipid formulations (liposomal amphotericin B, amphotericin B lipid complex, and amphotericin B colloidal dispersion) reduce nephrotoxicity and have different tissue distribution and dosing considerations.

Adverse effects are a major consideration and include nephrotoxicity, electrolyte disturbances (notably hypokalemia and hypomagnesemia), infusion-related reactions (fever, chills, rigors), anemia, and rarely hepatotoxicity. Monitoring of renal function and electrolytes is essential, and hydration and dose adjustments are common strategies to mitigate toxicity.

Resistance to amphotericin B is relatively uncommon but can occur through changes in fungal sterol content or biosynthesis.