Exam 4- 3 Antifungal Drugs Flashcards Preview

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Flashcards in Exam 4- 3 Antifungal Drugs Deck (23):
1

Antifungal Drugs

Drugs used to treat infections caused by fungi
-systemic
-topical

2

Fungi

Very large and diverse group of microorganisms
-broken down into yeasts and molds
-fungal infections also known as mycoses
-some fungi are part of the normal flora of the skin, mouth, intestines, vagina

3

Yeasts

Single cell fungi
-reproduced by budding
-can be used for
baking
alcoholic beverages

4

Molds

*multicellular
*characterized by long, branching filaments called hyphae

5

Mycotic Infections

Four General Types:
-Cutaneous
-Subcutaneous
-Superficial
-Systemic
can be life threatening
usually occur in immunocompromised host

6

Mycotic Infections:

Candida albicans
Vaginal candidiasis

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Candida albicans

*Due to antibiotic therapy, antineoplastics or immuniosuppressants (corticosteroids)
*May result in overgrowth and systemic infections
*Growth in the mouth is called thrush or oral candidiasis
*Common is newborn infants and immunocompromised patients

8

Vaginal candidiasis

*Yeast infection
*Pregnancy, women with diabetes mellitus, women taking antibiotics

9

Antifungal Drugs

Systemic
Topical

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Antifungal Drugs: Systemic

-amphotericin B, caspofungin, fluconazole, ketoconazole

11

Antifungal Drugs: Topical

*clotrimazole, miconazole, nystatin

12

Antifungal Drugs: Characteristics

*Broken down into major groups based on their chemical structure:
-Polyenes: amphotericin B and nystatin
-Imidazoles:ketoconazole
-Triazoles: fluconazole, itraconazole, voriconazole
-Echinocandins: caspofungin, micafungin
-Miscellaneous
griseofulvin, flucytosine

13

Mechanism of Action: flucytosine

*Also known as 5-fluorocytosine (antimetabolite)
*Taken up by fungal cells and interferes with DNA synthesis
*Result: fungal cell death

14

Mechanism of Action: griseofulvin

*disrupts cell division
*results: inhibit fungal mitosis (reproduction)

15

Mechanism of Action: Polyenes: amphotericin B and nystatin

*Bind to sterols in cell membrane
*Result: fungal cell death
*Do not bind to human cell membranes or kill human cells

16

Mechanism of Action: Imidazoles and triazoles: ketoconazole, fluconazole, itraconazole, voriconazole

*Inhibit fungal cell cytochrome P-450 enzymes, resulting in cell membrane leaking
*Lead to altered cell membrane
*Results: altered cellular metabolism and fungal cell death

17

Mechanism of Action: Echinocandins: caspofungin, micafungin

*Prevents the synthesis of glucans, which are essential components of fungal cell walls
*Causes fungal cell death

18

Indications:

*Systemic and topical fungal infections
*Drug of choice for the treatment of many severe systemic fungal infections is amphotericin B

19

Adverse Effects: Amphotericin B

fever
chills
cardiac dysrhythmias
Nausea and GI upset
Renal toxicity
Headache
Malaise
Hypotension
Tingling, numbness in hands and feet
lowered potassium and magnesium levels

20

Main concerns for Amphotericin B

*Renal toxicity
*Neurotoxicity: seizures and paresthesias

21

Antifungal Drugs: Adverse Effects/fluconazole

*Nausea, vomiting, diarrhea, stomach pain,
*Increased liver enzymes
*Use with caution in patients with renal and liver dysfunction

22

Antifungal Drugs: Adverse Effects/nystatin

*Nausea, vomiting, anorexia, diarrhea, local irritation, rash

23

Antifungal Drugs: Contraindications

*Liver failure
*Renal failure
*Porphyria (griseofulvin)
*Drug allergy