Antifungals


Amphotericin

Rapid Review

  • Mechanism of Action: Anti-fungal; binds to ergosterol in fungal membranes and causes intracellular contents to leak out.
  • Indications: used for severe or disseminated fungal infections (invasive aspergillosis, cryptococcal meningitis, blastomycosis, coccidiomycosis)
  • Contraindications: allergy to class/drug
  • Dosage: Dosage varies significantly based on formulation. Generally, a single test dosage (1 mg in 20 mL of 5% dextrose) is infused over 20-30 minutes with close monitoring. If tolerated, then give a single daily dosage of 0.25mg/kg.
  • Half-life: Up to 14 days; depending on dosage
  • Adverse Reactions: Associated with significant renal toxicity. May also cause fever, chills, muscle rigor, and hypotension
  • Special Considerations: May cause hypokalemia and hypomagnesemia. Should be supplemented with potassium and magnesium. IV fluids help minimize nephrotoxicity.

Pearls

Video Credit: Medicosis


Clotrimazole

Rapid Review

  • Mechanism of Action: Azole antifungal; inhibits 14-alpha demethylase and reduces fungal cell membrane synthesis.
  • Indications: Tinea infections (ringworm, jock itch, athletes foot), pityriasis versicolor, oropharyngeal candidiasis, vulvovaginal candidiasis
  • Contraindications: Allergy to drug/class
  • Dosage:
    • Tinea infections: Topical 1% cream applied bid x 2-4 weeks
    • Oropharyngeal infection: 10mg PO 5 times daily x 14 days
    • Vulvovaginal infection: 1 applicator 2% PV qhs x 3 days
  • Half-life: Unknown
  • Adverse Reactions: Itching, nausea, vomiting.
  • Special Considerations: Oral formulations may cause abnormal liver function tests in 10% of patients.

Pearls

Video Credit: Drug Talk


Fluconazole

Rapid Review

  • Mechanism of Action: Triazole antifungal; inhibits cytochrome P450 to prevent egosterol synthesis to increase cellular permeability.
  • Indications: Vaginal, oropharyngeal, or esophageal candidiasis. Systemic candida infections.
  • Contraindications: Allergy to drug/class, coadministration with drugs that prolong QT intervals
  • Dosage:
    • Vaginal candidiasis: Single 150mg dose PO
    • Esophageal/oropharyngeal candidiasis: 100mg PO q daily x 2 weeks
  • Half-life: 24 hours
  • Adverse Reactions: GI symptoms (nausea, abdominal pain, diarrhea), anaphylaxis, hepatotoxicity, QT prolongation
  • Special Considerations
  • Fluconazole is an antifungal medication used to treat candidal infections (e.g. vaginal yeast infection), tinea as well as invasive fungal infections.

Pearls

Video Credit: Drug Talk


Brandon Simpson, PA-C
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  • Blog - 25 Feb 2021