Questions – Antifungals

00:00 Okay, let's have a question.

00:03 The following medications act on the fungal cell wall except A) Flucytosine B) Ketoconazole C) Miconazole D) Nystatin and E) Amphotericin B Good you said Flucytosine.

00:23 Which of the following drugs is a drug of choice for Crytococcus? A) Ketoconazole B) Fluconazole C) Miconazole D) Terbinafine and E) Griseofulvin Right, fluconazole.

00:41 Now ketoconazole is a narrow spectrum antifungal agent with a significant number of side effects and adverse events.

00:47 It's not available in parental form.

00:50 And it's used in really mucocutaneous candidaisis and dermatophytes infections.

00:57 Miconazole is an azole as well.

00:59 It's used against skin infections.

01:02 Terbinafine and griselfulvin are medications that prodominantly focus on the skin because they bind to the stratum corneum.

01:09 If you remember where I had a picture of the stratum corneum before.

01:13 Fluconazole is the drug of choice in crytococcal infections, in particular cryptococcal meningitis.

01:19 It is also used for the secondary prevention of cryptococcal infections.

01:23 Other drugs useful in cryptococcal infections are the broad spectrum agents like itraconazole and amphotericin B and the narrow spectrum agent flucytosine which is similar to fluconazole.

01:37 Which of the following agents act by creating a pore in the cell wall? Flucytosine.

01:45 Terbinafine.

01:46 The polyenes Ketoconazole Indapamide.

01:53 The polyenes, right.

01:55 Flucytosine acts on the nucleus to inhibit nucleic acid synthesis.

02:01 Terbinafine binds to the stratum corneum of the skin and attaches to fungal cells to inhibit squalene breakdown.

02:09 The toxic squalene inhibits cellular function of fungal organisms.

02:13 Ketoconazole acts through ergosterol to create defects in the cell wall.

02:18 Indapamide though is a diuretic.

02:21 This has nothing to do with fungus and is just thrown in there as an extra choice.

02:27 Now the polyenes include amphotericin B and nystatin which create hydrophilic pores in the cell wall allowing the efflux of solutes from the cytoplasm.

02:37 And it also allows for toxic intermediates to develop through free radical formation inside the fungal cell wall.

02:44 That's it.

02:46 That's the fungal agents.

02:48 You did really well to sit through it.

02:51 You can go and write your exam and feel confident and show them what you know.