antifungals Flashcards
3 groups of fungal infections
-Systemic mycoses
-Subcutaneous mycoses
-Superficial mycoses
-think about where the pt was- did they travel -> broader spectrum antifungals
systemic mycoses
-Includes soft tissue infections, UTI, pneumonia, meningitis or septicemia
-Causative pathogens include Aspergillus, Blastomyces, Candida, Coccidiodes, Cryptococcus and Histoplasma
-Some infx – geographical, can occur in immunocompetent or immunocompromised
-Other infx – more likely to occur in immunocompromised or debilitated pts only
subcutaneous mycoses
-Caused by puncture wounds contaminated with soil fungi
-Infx include chromomycosis, scedosporium and sporotrichosis
superficial mycoses
-Infx of nails, skin and mucous membranes usually caused by dermatophytes or yeasts
-Dermatophytes – Epidermophyton, Microsporum, Trichophyton. Dermatophyte infx include tinea pedis (athletes foot), tinea capitis or corporis (ringworm) and tinea cruris (jock itch)
-Yeasts – Candida albicans and non-albican species species (ex Malassezia furfur)
-Candida infx include thrush, vaginal infx and diaper rash
-Malassezia furfur infection – Tinea Versicolor. Primarily treated with selenium sulfide shampoo
classification of antifungals: polyene class
-amphotericin
-natamycin
-nystatin
classification of antifungals: azole derivatives
-miconazole
-clotrimazole
-econazole
-fluconazole
-itraconazole
-ketoconazole
-voriconazole,
-posaconazole
classification of antifungals: allylamine drugs
-naftifine
-terbinafine
-butenafine
classification of antifungal drugs: echinocandin class
-capsofungin
-micafungin
-anidulafungin
antifungals: miscellaneous
-ciclopirox
-flucytosine
-griseofulvin
-tolnaftate
amphotericin B
-Fungizone, Amphotec, Ambisone, Abelcet (last three are lipid form)
-Available IV*, Fungizone also available topical
-Not absorbed PO
-MOA- binds to ergosterol in fungal cell membrane and increase cell membrane permeability
-Indications: Broad spectrum antifungal. Used for !systemic infections! due to aspergillus, blastomyces, candida, coccidiodes, cryptococcus and histoplasma (the bad ones)
-Liposomal amphotericin B or Lipid Complex amphotericin B + Flucytosine PO used for cryptococcal meningitis induction phase
-must give VERY slow and HYDRATE
amphotericin B ADRs and cons
-amphoterible
-chills, fever, vomiting, H/A , renal and hepatic impairment, anemia, hypokalemia, hypomagnesaemia, hypotension, phlebitis
-lipid formulations have less ADRs
-High cost, difficulty of administration (solubility and stability factors with IV use) and side-effect profile don’t make it the first line drug
-Most often given in combination with other antifungals to reduce toxicity
cultures
-fungal infection- takes 2 weeks to swab
-bacteria- 24-48 hrs
-if bacteria comes back neg we assume fungus
nystatin
-nycolog, mycostatin
-available in topical form only - apply to skin, oral or vaginal mucosa for Candida infections
-powder, suspension (for oral)
-needs to be applied multiple times a day in a thin layer
-One of the preferred agents for treatment of superficial candidal infections
-swish and spit usually, if down the throat -> swish and swallow
natamycin
-natasyn
-ophthalmic suspension for TX of fungal blepharitis, conjunctivitis or keratitits caused by Aspergillus sp. and Candida sp.
azole derivatives
-MOA - inhibits synthesis of fungal lipid ergosterol
-Spectrum - Active against a wide range of fungi including dermatophytes and yeasts
-Indications - Topical for superficial infx, orally for more severe superficial infx as well as for subcutaneous and systemic infx and IV for systemic infections
-Kinetics - Well absorbed PO, some require acidic medium for absorption
-clotrimazole
-econazole
-fluconazole
-ketoconazole
-itraconazole
-miconazole
-posaconazole
-voriconazole