Exam 4- 3 Antifungal Drugs

Question 1

Antifungal Drugs

Answer 1

Drugs used to treat infections caused by fungi

• systemic
• topical

Question 2

Fungi

Answer 2

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

Question 3

Yeasts

Answer 3

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

Question 4

Molds

Answer 4

• multicellular

* characterized by long, branching filaments called hyphae

Question 5

Mycotic Infections

Answer 5

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

Question 6

Mycotic Infections:

Answer 6

Candida albicans

Vaginal candidiasis

Question 7

Candida albicans

Answer 7

• 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

Question 8

Vaginal candidiasis

Answer 8

• Yeast infection

* Pregnancy, women with diabetes mellitus, women taking antibiotics

Question 9

Antifungal Drugs

Answer 9

Systemic

Topical

Question 10

Antifungal Drugs: Systemic

Answer 10

-amphotericin B, caspofungin, fluconazole, ketoconazole

Question 11

Antifungal Drugs: Topical

Answer 11

*clotrimazole, miconazole, nystatin

Question 12

Antifungal Drugs: Characteristics

Answer 12

*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

Question 13

Mechanism of Action: flucytosine

Answer 13

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

Question 14

Mechanism of Action: griseofulvin

Answer 14

• disrupts cell division

* results: inhibit fungal mitosis (reproduction)

Question 15

Mechanism of Action: Polyenes: amphotericin B and nystatin

Answer 15

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

Question 16

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

Answer 16

• 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

Question 17

Mechanism of Action: Echinocandins: caspofungin, micafungin

Answer 17

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

Question 18

Indications:

Answer 18

• Systemic and topical fungal infections

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

Question 19

Adverse Effects: Amphotericin B

Answer 19

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

Question 20

Main concerns for Amphotericin B

Answer 20

• Renal toxicity

* Neurotoxicity: seizures and paresthesias

Question 21

Antifungal Drugs: Adverse Effects/fluconazole

Answer 21

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

Question 22

Antifungal Drugs: Adverse Effects/nystatin

Answer 22

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

Question 23

Antifungal Drugs: Contraindications

Answer 23

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