Polyene antifungals

Polyenes bind ergosterol in the fungal cell membrane and form channels through it, so potassium, sodium and other contents leak out and the cell dies. They bind the cholesterol of human cells less strongly, but enough for amphotericin B to harm human tissue, the kidney most. Nystatin is barely absorbed from the gut, so it acts only in the mouth, gut or skin.

• Amphotericin BReserved for dangerous infections. Infusion reactions are worst with the first doses and ease later. Lipid and liposomal forms cause fewer chills and less kidney damage than the conventional form.
• NystatinUnlike its relative amphotericin B, nystatin is not given IV: barely absorbed from the gut, it works only where it touches, with few side effects.

• Life-threatening systemic fungal infections
• Cryptococcal meningitis
• Aspergillosis
• Visceral leishmaniasis
• Mouth, gut and skin thrush (nystatin)

• Fever, chills and rigors during the infusionKnown for
• Kidney damage (nephrotoxicity)Known forSerious
• Low potassium (hypokalemia)Known forSerious
• Low magnesium (hypomagnesemia)
• Anemia
• Low blood pressure
• Nausea and vomiting
• Pain and phlebitis at the infusion site
• Arrhythmias and cardiac arrest with overdoseSerious
• AnaphylaxisSerious

What the class has in common. Each drug's card has its own, and Known for marks what an exam expects you to know.

• Amphotericin B: check kidney function, potassium and magnesium often; fluids and salt before doses can lessen kidney damage.
• Avoid other kidney-toxic drugs, such as aminoglycosides and ciclosporin, alongside amphotericin B where possible.
• Conventional and lipid forms of amphotericin B are dosed differently: check the product, since overdose can stop the heart.
• Nystatin stays in the gut and on the skin, so it lacks the systemic toxicity of amphotericin B.

Written for biofideX in plain words, after checking these references:

• Amphotericin B for injection: label (DailyMed)
• Amphotericin B liposome for injection: label (DailyMed)
• Nystatin tablets: label (DailyMed)
• Amphotericin B (NCI Thesaurus)
• Nystatin (NHS)

For learning pharmacology, not for treatment decisions: no doses are given, and a prescriber, pharmacist or the product's own label is the word on any one patient. Spotted a mistake? Tell us and we'll correct it.