Anti-fungal agents: Short Notes

Amphotericin B

• Used for systemic fungal infections
• Affinity for ergosterol
• Binds and disrupts cell membranes, causing leakage of low mw compounds
• IV 2-3 months - May want to premedicate with prostaglandin inhibitors

Nystatin

• Only effective against Candida albicans
• Same mechanism of action as Amphotericin B

Griseofulvin

• Used for severe skin, hair and nail infections
• Inhibits microtubule formation and formation of the mitotic spindle
• Accumulates in the stratum corneum, preventing fungal penetration
• Orally – 3 weeks to 12 months

Azoles (imidazoles and triazoles)

• Used primarily for mucocutaneous candidiasis and dermatophytosis
• Inhibits the synthesis of ergosterol
• * BLOCKS cytochrome p-450, causing other drug levels to INCREASE
• IV, orally, or as an ointment or cream

Allylamines (naftifine, terbinafine)

• Used primarily for dermatophytes
• Inhibit ergesterol synthesis (oxidation of squalene) - FUNGICIDAL
• Orally or as a topical treatment
• Oral form is given for 3 months for nail infections
• * Blocks CYP2D6 enzyme – causes less concern about drug interactions

5-fluorocytosine

• Used primarily in combination with Amphoteracin B or fluconazole to treat cryptococcosis
• Used alone to treat types of chromomycosis
• A nucleotide analoge
• Inhibits protein synthesis by blocking steps in DNA and RNA synthesis
• Orally

Morpholines (Amorolfine)

• Used to treat dermatophytoses
• Blocks steps in ergosterol synthesis
• Topical preparations

Ciclopirox

• Used to treat fungal infections of nails
• Has affinity for trivalent cations such as iron
• Inhibits the enzymes that use iron as a cofactor
• FUNGICIDAL
• Cream and nail lacquer (the only topical treatment available)

Echinocandins (caspofungin)

• Used to treat systemic aspergillosis and severe candidiasis
• Inhibits the synthesis of D-glucan, a component of the fungal cell wall
• IV administration

Category: Pharmacology Notes