Antifungal drugs Flashcards
Cutaneous mycoses - types
- tinea capitis (dermatophytoses)
- tinea corporis (dermatophytoses)
- tinea cruris (dermatophytoses)
- tinea pedis (dermatophytoses)
- tinea unguium (dermatophytoses)
- Tinea versicolor
fungal cell - erogsterol synthesis - pathway and enzymes
Squalene –> Squalene epoxide (Squalene epoxidase)(LANOSTEROL SYNTHESIS)
Squalene epoxide –> Lanosterol
Lanosterol –> Ergosterol (14-α-demethylase)
ertosterol –> cell membrane
fungal cell - cell ergosterol synthesis - pathway and enzymes - lanosterol synthesis
Squalene –> Squalene epoxide (Squalene epoxidase) –> Lanosterol
fungal cell - ergosterol synthesis - pathway and enzymes - Ergosterol synthesis
Lanosterol –> Ergosterol (14-α-demethylase)
drugs that interrupt cell ergosterol synthesis pathway in fungus (and enzymes affected)
- Terbinafine block Squalene epoxidase (Lanosterol synthesis)
- Azoles blocks 14-α-deamethylase (Cytochrome P-450 that converts lanesterol to ergosterol) (Ergosterol syntehsis)
Antifungul drugs - group according to action (not the names of the drugs)
- Lanosterol synthesis inhibitor
- Ergosterol synthesis inhibitor
- Cell wall synthesis inhibitor
- Nucleic acid synthesis inhibitor
- Membrane pores formers
- Griseofulvin
Membrane pores formers - drugs
polyenes
- Amphotericin B
- Nystatin
Membrane pores formers - drugs - and mechasnim of action
- Amphotericin B 2. Nystatin
Binds to ergosterol (unique to fungi) –> membranes pores that allow leakage of electrolytes
Membrane pores former drugs - harmless for host cell - why
Because ergosterol is UNIQUE TO FUNGI
Amphotericin B - clinical use
- SERIOUS SYSTEMIC MYCOTIC INFECTIONS : Histoplasmosis, Blastomycosis, Coccidioidomycosis, Mucor, Candida, Cryptococcus
- Naegleria Fowleri
- Leismania Donovani
Amphotericin B - meningitis
- with/without flucytosine for cryptococcal meningitis
- Intrathecally for fungal meningitis
Amphotericin B - administrate with (and why)
supplement K+ and Mg2+ because of altered renal tubule permeability
Amphotericin B - toxicity
- fever/chills (shake and bake)
- Hypotenesion
- nephrotoxicity
- arrhythmias
- anemia
- IV phlebitis
Amphotericin B - solution of toxicity
- Hydration decreases nephrotoxicity
2. Liposomal amphotericin –> decreased toxicity
Nystatin - clinical use
TOPICAL USE ONLY (TOO TOXIC FOR SYSTEMIC USE)
- oral candidiasis (swish and swallow)
- topical for diaper rash or vaginal candidiasis
Antifungul drugs - Nucleic acid synthesis inhibitor
Flucytosine
Flucytosine - mechanism of action
Inhibits DNA and RNA biosynthesis by conversion to 5-fluorouracil by cytosine deaminase –> inhibits thymidylate synthetase
Flucytosine - clinical use
Systemic fungal infections (esp meningitis caused by Cryptococcus) in combination with amphotericin B
Flucytosine - toxicity
Bone marrow suppression
Antifungul drugs - Ergosterol synthesis inhibitor - drugs
-AZOLE
clotrimazole, fluconazole, intraconazole, ketoconazole, miconazole, voriconazole
azoles - mechanism of action
inhibit fungal stero (ergosterol) synthesis by inhibiting the cytochrome P-450 enzyme that converts lanosterol to ergosterol (14-α-demethylase)
azoles - clinical use
Local and less serious systemic mycoses:
- Fluconazole: chronic suppression of cryptococcal meningitis in AIDS patients, all types of candidal infections, LOCAL systemic mycoses
- Intraconazole: (LOCAL systemic mycoses) Blastomyces, Coccidioides, Histoplasma
- Clotrimazole, miconazole: topical fungal infection
Fluconazole - clinical use
- chronic suppression of cryptococcal meningitis in AIDS patients,
- all types of candidal infections
- LOCAL systemic mycoses
Intraconazole - clinical use
(LOCAL systemic mycoses) Blastomyces, Coccidioides, Histoplasma
Clotrimazole, miconazole - clinical use
topical fungal infection
Azoles - toxicity
- testosterone synthesis inhibition –> gynecomastia (esp ketoconazole)
- liver dysfunction (inhibits P450)
fungus - Lanosterol synthesis inhibitor - drugs
Terbinafine
Terbinafine - mechanism of action
inhibits the fungal enzyme squalene epoxidase (Lanosterol synthesis inhibitor)
Terbinafine - clinical use
Dermathophytes (esp onychomycoses)
Terbinafine - toxicity
- GI upset
- headaches
- hepatotoxicity
- Taste disturbance
Antifungul drugs - Cell wall synthesis inhibitor - drugs
Echinocandins –> 1. Anidulafungin 2. caspofungin
3. micafungin
Echinocandins - drugs
- Anidulafungin
- caspofungin
- micafungin
Echinocandins - drugs and mechanism of action
Echinocandins –> 1. Anidulafungin 2. caspofungin
3. micafungin
inhibit cell wall synthesis by inhibiting synthesis of β-glucan
Echinocandins - inhibit cell wall synthesis by inhibiting synthesis of
β-glucan
Echinocandins - clinical use
- invasive aspergilosis
2. Candida
Echinocandins - drugs and toxicity
Echinocandins –> 1. Anidulafungin 2. caspofungin
3. micafungin
GI upset, flushing (by histamine release)
Griseofulvin - mechanism of action
interferes with microtubule formation –> disrupts mitosis
DEPOSITIS IN KERATIN-CONTAINING TISSUES (EG. NAILS)
Griseofulvin - clinical use
- oral treatment of superficial infections
2. inhibits growth of dermatophytes (tinea, ringworm)
Griseofulvin - toxicity
- teratogenic 2. carcinogenic 3. confusion 4. headaches 5. increased cytochrome P-450 and warfarin metabolism
Tinea versicolor - treatment
- topical and/oral antifungul medication
2. selenium sulfate
Candida ablicans - treatment
topical azole for vagina
nystatin, fluconazole or caspofungin for oral/esophageal
caspofungin, fluconazole or amphotericin B for systemic
Mucormycosis treatment
- surgical debridement
2. amphotericin B
Pneumocystis jirevecii - Treatment/prophylaxis/start prophylaxis when
- TMP-SMX
- Pentamidine
- dapsone (only prophylaxis)
- atovaquone
CD4 cound drops under 2 hundred cells/mm3 in HIV patients
Sporothrix schenckii - treatment
intraconazole or potassium iodide
terbinafine - toxicity
- GI upset
- headaches
- hepatotoxicity
- Taste disturbance
Echinocandins - drugs and toxicity
Echinocandins –> 1. Anidulafungin 2. caspofungin
3. micafungin
GI upset, flushing (by histamine release)
griseofulvin - toxicity
- teratogenic 2. carcinogenic 3. confusion 4. headaches 5. increased cytochrome P-450 and warfarin metabolism
invasive aspergilosis - treatment
echinocandins
antifungal drugs - P450
Griseofulvin –> induces
Azoles –> inhibits
antimycobacterial drgus - P450
Rifampin –> induces
isoniazid –> inhibits