Antifungals Flashcards
when you think Fungus you generally think of?
Candida spp. is a ?
Cryptococcus spp. is a ?
Aspergillus spp. is a ?
yeast and mold
Candida spp. is a yeast
Cryptococcus spp. is a yeast
Aspergillus spp. is a mold
What type of patients are at risk for fungal infections?
-Increasing number of immunocompromised and immnocompetent
-Can occur in immunocompetent patients as well
→ patients that have chronic catheters or chronic antibiotic use
What are the different routes of transmission for fungal infections?
- Respiratory→ pores inhalation (aspergillus is present in the soil)
- Traumatic implantation
- Direct contact (dermatoid infections)
What are the different categories of anti fungal agents available ?
- Allylamines (topical agents)
- Polyenes
- Azoles
- Echinocandins
- Miscellaneous→ Flucytosine
Allylamines:
- ) Forumulations available?
- ) Indications?
- )MOA?
1.) Topical agents
- ) Indications:
- Tinea cosporis (ring worm)
- Tinea pedis (athlete’s foot)
- Tinea cruris (jock itch)
- Onychomycosis (terbinafine) → nail fungus - )MOA:
- inhibition of squalene epoxidase → reducing fungal cell membrane ergosterol synthesis (allylamines-ES stands for squalene epoxidase)
Terbinafine:
- ) Excretion?
- )Monitoring?
- ) Great for treating fungal infections of the?
1.) Excretion: Renally eliminated, caution in hepatic impairment
2.) Monitoring:
-SCr
-LFTs
*at baseline and throughout the treatment)
-CBC
→ only if > then 6 weeks of tx in immunodeficient patients
- ) great for treating fungal infections of the
- fingernails → esp nail fungus
- toenails→ esp nail fungus
- tinea
What is the mechanism of action for azoles?
- Inhibition of 14 alpha-demethylase which converts lanosterol to ergosterol → disruption in cell membrane synthesis
- also blocks steroid synthesis in humans
What are the indications for use of Imidazoles?
Indications: Tinea cotporis Tinea pedis Tinea cruris Oropharyngeal candidiasis Vulvovaginal candidiasis
What Imidazole agents do we have available?
Ketoconazole
Clotrimazole
Miconazole
Ketoconazole:
- ) Imidazole or Triazole?
- ) Effective against? High failure rate in?
- ) Excretion?
1.) Imidazole
- )Effective against:
- Candida spp.
- Blastomycosis,
- Histoplasmosis(high failure rates)
3.) Excreted in feces
Ketoconazole:
- ) CYP interactions?
- ) Considerations
- ) -CYP450 3A4 substrate→ CYP inhibition = drug interactions!!!
- ) Needs acidic gastric pH for absorption-think interactions with tums and omperazole (will make t & o not work)
Ketoconazole:
- ) Side Effects?
- ) C/I’s?
- ) Can cause QTc prolongation → black box warning
2. ) C/I in patients with hepatic impairment
- )What Triazole agents do we have available?
2. ) What do we commonly associate Triazole agents with?
1.) Fluconazole Itraconazole Voriconazole Posaconazole Isavuconazole
2.) Systemic invasive fungal infections (REALLY BAD INFECTIONS)
Triazoles:
- ) MOA?
- ) Fungicidal or fungal static?
- ) MOA: inhibition of CYP450-34A and sterol C-14alpha-demethylation
- ) Primarily fungistatic
How are the newer triazoles different from the older triazoles?
The newer triazoles have.... less hormonal inhibition, broader spectrum, less toxic, better tissue distribution
Fluconazole: (Diflucan)
1.) Indication?
- ) Indication:
- Candidiasis: invasive →(oroesophageal/urogenital/vulvovaginal)
- ProphylaxisinBMTrecipients/txtpatients
- Cryptococcosis: consolidation phase (used after initial treatment)
Fluconazole:
- ) DDI’s?
- ) This drug is beneficial also for _____ b/c it can ……?
- ) Side effects and dose adjustments?
- ) CYP interactions:
- Minor inhibition of CYP 3A4
- Moderate inhibitor of CYP 2C9
2.)Fungal meningitis because it can cross the BBB
→ Can penetrate the CNS
- )Side effects and dose adjustments:
- Needs to be adjusted in renal failure
- Check QTc
- Pt’s may experience Alopecia
Itraconazole:
- ) Indication?
- ) What DDI’s do you have to be aware of and why?
1.)Indication:
-Candidiasis: oropharengeal and esophageal
→ Maybe a step down therapy in Aspergillosis ( NOT 1st line!)
2.) warfarin b/c this drug is ***99% protein bound
Itraconazole:
1.) Formulations available? What do you have to considerations when giving the dose?
- )
- Available in capsules in solution BUT, CANNOT interchange
- Capsules need to be given w/ meal
- Solution should be given on an empty stomach and is preferred formulation
Itraconazole:
1.) Side effects?
2.) C/I’s?
- )
- HTN
- Edema
- Hypokalemia
- QTc-prolongation
2.) Cardiac Patients- QTc prolongation