Antifungals

Question 1

Examples of fungal (mycoses) infection

Answer 1

Athletes foot, ringworm, candida (yeast/thrush). Can be located on the skin, mucous membranes, hair, nails. Deep infections can spread to blood and internal organs and be life threatening.

Question 2

Two forms of fungus

Answer 2

Yeast or mold

Question 3

Azoles are ideal for ___ infections

Answer 3

Superficial

Question 4

Azoles

1. MOA
2. Adverse effects
3. Drug interactions

Answer 4

1. Prevents ergosterol synthesis= membrane disruption. Also decreases testosterone and cortisol production
2. Allergies and GI. Relatively few.
3. P450 inhibitor. Increases toxicity of many drugs being taken. Should not be used with amphotercerin B bc needs ergosterol to form pore.

Question 5

In addition to preventing ergosterol synthesis, azoles decrease ____ levels

Answer 5

Testosterone and cortisol levels.

Question 6

Ketoconazole admin and fact

Answer 6

Topical.

Less selective for fungal enzymes than others = more side effects

Question 7

Fluconazole. Bioavailability?

Answer 7

High. Can penetrate CNS

Question 8

Itraconazole is drug of choice for

Answer 8

Drug of choice for histoplasmosis

Question 9

Voriconazole

Answer 9

High bioavail.
P450 inhibitor. Will cause other drug levels to increase.
30% of patients report visual disturbances

Question 10

Posaconazole was developed for what

Answer 10

Developed for prophylactic use by immunocompromised pts.

Question 11

Echinocandins MOA and admin

Answer 11

MOA: Disrupts fungal cell wall.

Only available IV. Well tolerated with few side effects- GI and flushing.

Question 12

Polyene Macrolide MOA

Answer 12

Binds to ergosterol and forms pore. Do not take with azoles because azoles prevent ergosterol formation.

Question 13

Amphotericin B
Spectrum
Pharmacokinetics
Adverse effects

Answer 13

Wide spectrum with high toxic potential.
Infrequent resistance.
Give slow IV, liver eliminates.
Low TI, infusion related toxicity (fever, chills) renal impairment, anemia.

Question 14

Admin of nystatin and natamycin

Answer 14

Both topical.

Natamycin is the only ophthalmic anti fungal med.

Question 15

Allylamines MOA

Adverse effects

Answer 15

Inhibits enzyme squalene epoxidase. This blocks the synthesis of ergosterol and squalene levels become toxic.
Adverse effects when given orally: GI problems, rash, HA.
When given topically: redness when in contact with mucous membranes.

Question 16

Terbanifine admin and main use

Answer 16

Topical and oral

Fungal nail Tx

Question 17

Naftifine admin

Answer 17

Topical

Question 18

Flucytosine 
MOA: 
resistance: 
Pharmacokinetics:
Adverse effects:

Answer 18

MOA: Enters fungal cell and disrupts DNA/protein synthesis. Converted to 5-FU intracellularlly (antimetabolite)
Resistance is low if given with another anti fungal.
Oral ONLY, penetrates CNS
Adverse: decrease neutrophils, platelets, BM. GI probs.

Question 19

Flucytosine adverse effects

Answer 19

Decrease in neutrophils, platelets, BM. GI probs.

Question 20

Flucytosine was originally developed as

Answer 20

An anti-cancer drug. But works well as an anti fungal.

Question 21

Rifampin can shorten half life of which Azole?

Answer 21

Ketoconazole.