Chapter 22 Drug Therapy for Fungal Infections

1. A patient develops itching and burning of the vaginal vault while taking an anti-infective to treat strep throat. What fungal agent has most likely caused the burning and itching?

1. A)  Cryptococcus neoformans
2. B)  Candida albicans
3. C)  Aspergillus
4. D)  Dermatophytes

Ans: B
Feedback:
Growth of Candida organisms is normally restrained by intact immune mechanisms and bacterial competition of nutrients. When these restraining forces are altered (antibacterial drug therapy), fungal overgrowth and opportunistic infection can occur. Cryptococcus neoformans organisms evade normal immune defense of phagocytosis. Aspergillus organisms produce protease. Dermatophytes grow on cool body surfaces.

2. A patient is being treated with amphotericin B for a fungal infection of the urinary tract. What is the action of amphotericin B?

1. A)  It binds to ergosterol and forms holes in the membrane.
2. B)  It binds to an enzyme required for synthesis of ergosterol.
3. C)  It disrupts the fungal cell walls rather than the cell membrane.
4. D)  It inhibits glucan synthetase required for glucan synthesis.

Ans: A Feedback:

Amphotericin B binds to ergosterol and forms holes in the membrane, causing leakage of fungal cell contents and lysis of the cell. The azole drugs bind to an enzyme that is required for synthesis of ergosterol. This action causes production of a defective cell membrane, which allows leakage of intracellular contents and destruction of the cell. Echinocandins disrupt fungal cell walls rather than fungal cell membranes. They inhibit glycan synthetase, an enzyme required for synthesis of glucan.

3. A patient is being treated for a severe fungal infection with amphotericin B. What is the expected length of treatment for this patient?

1. A)  1 to 2 weeks
2. B)  3 to 6 weeks
3. C)  4 to 12 weeks
4. D)  15 to 18 weeks

Ans: C Feedback:

Because of the toxicity of amphotericin B, the drug is used only for serious infections. It is usually given for 4 to 12 weeks. Amphotericin B is not given for 1 to 2 weeks, 3 to 6 weeks, or 15 to 18 weeks.

Page 1

4. A patient is given Abelcet instead of amphotericin B. What is the advantage of Abelcet over amphotericin B?

1. A)  It is a newer medication with a lower cost.
2. B)  It is the same as amphotericin B in hepatotoxicity.
3. C)  It reaches higher concentration in diseased tissue.
4. D)  It constricts afferent renal arterioles to reduce blood flow.

Ans: C
Feedback:
Lipid formulations, such as Abelcet, reach higher concentrations in diseased tissues than in normal tissues, so larger doses can be given to increase therapeutic effects. Abelcet does not cost less than amphotericin B. Abelcet has fewer side effects than amphotericin B. Amphotericin B constricts afferent renal arterioles to reduce blood flow.

5. A child with a serious fungal infection is receiving amphotericin B parenterally. Which of the following minerals will the patient most likely be required to receive?

1. A)  Chloride
2. B)  Magnesium
3. C)  Glucose
4. D)  Sodium

Ans: B
Feedback:
Hypomagnesemia may occur, which will require the administration of magnesium. The patient is less at risk for changes in chloride, glucose, or sodium.

6. A patient is receiving oral nystatin suspension for a fungal infection of the mouth. Which of the following adverse effects is most likely to be experienced with this form of nystatin?

1. A)  Local irritation
2. B)  Burning
3. C)  Nausea
4. D)  Urinary urgency

Ans: C
Feedback:
Oral use of nystatin produces the following adverse effects: nausea, vomiting, and diarrhea. The vaginal application of nystatin produces the following adverse effects: local irritation and burning. Urinary urgency is not an adverse effect associated with nystatin.