Antifungal Agents Flashcards
Interactions between this drug and cell membrane compnents can result in the formation of pores lined by hydrophilic group present in the drug molecule
Nystatin
- Polyene antifungal drugs amphotericin B and nystatin are ampiphatic moleciles
A 14 year old patient has experience severe headache and double vision for a month. His temperature is 38.6. His CSF culture was positive for cryptococcal antigen. Which of the following drugs wiuld be apropriate (not intrathecally)
Fluconazole
- Amphotericin B- intrathecal
If amphoteric B is administerd, the patient shpuld bne premedicated with ________
Diphenhydramine, Ibuprofen, Predsinone
Prophylaxis for candida infection in the bloodstream
None
Prophylactic against other fungi may be effective in some instances, including suppression of cyptococcal meningitis in AIDS patients with __________
Fluconazole
Initial treatmentfor C. immitis pulmonary symptoms
none
If persistent pulmonary c. immitis or disseminated disease.
Itraconazole
Serious cardiac effects have occured when this drug was taken by patients using antihistamines astemizole or terfenadine
Ketoconazole
Common azoles for esophageal candidiasis
“swish and swallow” formualtion of clotrimozaole and nystatin
Liposomal formulations of amphoteric B
- They decrease the nephrotoxicity of amphotericin B
- do not have wider antifungal spectrum
___________can cause renal tubular acidosis with magnesium and potassium wasting
Amphotericin B
Selective toxicity of Flucytosine
Mammalian cells have low levels of permease and deaminase
________ is responsible for the elimination of ketoconazole, itraconazole, posaconazole, voriconazole
Liver metabolism
Broadest spectum triazole
Posaconazole
- only azole with activity against Rhizopus
Elimination of griseofulvin
Biliary excretion
Amphotericin B
Binds to ergosterol in fungal cell membranes, forming leaky pores
Used in Candidemia and infections caused by aspergillus, blastomyces, cryptococcus, histoplasma, mucor
Multiple forms, IV for systemic infections (liposomal forms less nephrotoxic) Topical or ocular/bladder inferctions
SE: nephrotoxicity is dose limiting, additive with other nephrotoxic drugs. Infusio reactions (chills, fever, muscle, spasms, hypotension)
Azoles
Inhibit fungal P450 dependent enzymes blcoking ergosterol synthersis. Resitance can occur with long term use
Aspergillosis (voriconazole). Blastomycosis (Itraconazole,fluconazole). Mucormycosis (posaconzaole). Alternantive drugs in candidemia and infections caused by aspergillus, blastomyces, crytpococcus and histoplasma
Various topical and oral forms for dermatophytoses Oral, and parenterl for,s for mycoses (fluconazole, itraconazole, posaconazole, voriconazole). Most azoles undergo hepatic metabolism. FLuconazole is eliminated unchanged in urine. FLuconaole has excellent CNS pentration
SE; Ketoconazole is rarely used in systemic fungal infections owing to its inhibition of hepatic and adrenal P450s. Other Azoles are less toxic, but may cause GI upsets and rash. Voriconazole causes visual disturbances and class D risk in pregnancy
Echinocandins
(Caspofungin, micafungin, anidulafungin)
Inhibit B-glucan synthase decrease fungal cell wall synthesis
treatment of candidemia. Caspofungin is also used as salvage therapy in aspergillosis
IV forms. Micafungin increases levels of nifedipine and cyclosporin. Anidulafungin: no drug-drug interactions
SE: gastrointestinal distress, flushing from histamine release
Flucytosine
Inhibits DNA and RNA polymerases
Synergistic with amphotericin B in candidemia and cryptococcal infections
Oral; enters cerebrosponal fluid. Renal elimination
SE: bone marrow suppresion
Terbinafine, Naftifine
Inhibits epoxidation of squalene. Squalene accumulation is toxic to fungi
Used in mucocutaneous fungal infections. Accumualtes in keratin
Oral. long duration of action (weeks)
SE: GI upsets, headache
