Antifungals Flashcards
The drug that is most effective against ONYCHOMYCOSIS prevents the synthesis of ergosterol by inhibiting what enzyme
(ok 2nd order question!)
SQUALENE EPOXIDASE
Griseofulvin is stricly for tx of SUPERFICIAL mycoses and works by what MOA?
It in DISRUPTS THE MITOTIC SPINDLE AND LEADS TO INHIBITION OF MITOSIS
• The three most common systemic fungal infections in humans are:
- Candidiasis
- Cryptococcosis
• Aspergillosis
Which two meds can be used to treat Superfifial mycosis BOTH topically and systemically?
- Terbinafine (allyalmime)
- Ketoconazole (azole)
- ________________binds to ergosterol, forming pores in the cell membrane.
- The pores allow leakage of intracellular ions and macromolecules, leading to cell death.
Amphotericin B
name that antifungal
- Broad spectrum and fungicidal action: useful for nearly all life-threatening fungal infections.
- Often used as initial induction regimen to rapidly reduce fungal burden.
Amphotericin B
___________is the preferred treatment for deep fungal infections during pregnancy.
Amphotericin B
in order to attenuate the renal damage that this drug causes, sodium loading is done where saline infusion is administered with amphotericin B.
what drug requires these measures?
Amphotericin B
• Converted intracellularly first to 5-fluorouracil (5- FU) and then to 5-fluorodeoxyuridine monophosphate (5-FdUMP) which inhibits thymidylate synthetase, thus blocking synthesis of dTMP.
flucytosine
• Combination of flucytosine and _________is synergistic.
amphotericin B
whats the most common AE of Flucytosine
Bone marrow toxicity
name the 3
IMIDAZOLES (azoles)
-the rest are
TRIAZOLES (more specific)
- Itraconazole
- Fluconazole
- Voriconazole
• Posaconazole
• Ketoconazole
- Miconazole
- Clotrimazole
which type of drug inhibits (fungal cytp450 enzyme) 14-α-sterol demethylase which catalyzes the conversion of lanosterol to ergosterol.
AZOLES
- Synthetic allylamine.
- Available in oral formulation.
- Causes accumulation of toxic levels of squalene in the fungal cell, making it fungicidal under most circumstances.
- Does NOT affect the P450 system and has no significant drug interactions.
TERBINAFINE
Pulse or intermittent dosing with____________is as effective in onychomycoses as continuous dosing because the drug persists in the nails for several months.
itraconazole
Ketoconazole, fluconazole and itraconazole are commonly used orally (systemically) for the treatment of ____________
dermatophytoses
this drug has one use and that is dermatophytosis.
Largely replaced by newer antifungal drugs like itraconazole and terbinafine.
Enters susceptible fungal cells by energy-dependent process. Interacts with microtubules of the fungus to disrupt mitotic spindle and inhibit mitosis.
induces liver P450 enzymes, thus increasing the metabolism of a number of drugs, including warfarin.
GRISEOFULVIN
fun facts:
- Fungistatic drug.
- Absorption improved when given with fatty foods.
T or F
Nystatin has real bad AE due to its high level of toxicity.
NO!
Nystatin is not absorbed from the GI tract, skin, or vagina. As a result it has little significant toxicity.
note: Other than the bitter taste and occasional complaints of nausea, adverse effects are uncommon.
why cant Pneumocystis jirovecii, the organism responsible for Pneumocystis pneumonia (PCP), be treated with antifungals and insread is treated with antiprotozoals.
Because it responds to antiprotozoal drugs, rather than to antifungals. Pneumocystis does not synthesize ergosterol, thus agents that target ergosterol, such as amphotericin B and the azoles are ineffective.
what is the most common opportunistic infection in HIV-infected patients.
PNEUMOCYSTIS JIROVECII PNEUMONIA
The first-line therapy of pneumocystosis which is also the standard chemoprophylactic drug for the prevention of P jiroveci infection in immunocompromised individuals.
co-trimoxazole
(trimethoprim plus sulfamethoxazole)
Note: Patients with moderate-to-severe disease should also be given corticosteroids. The preferred corticosteroid is prednisone.
