Pharmacology Ch 44 - Fungal Drugs

4. dimorphic fungi

a. Capable of growing as yeasts at one temperature and as molds at another temperature

3. dermatophytes

b. Mold-like fungi

1. Your patient is receiving IV amphotericin B-Fungizone. Which of the following electrolyte imbalances may be induced by this therapy? a. Hypokalemia b. Hyponatremia c. Hyperkalemia d. Hypernatremia

1. (a) Amphotericin B (Fungizone) may induce hypokalemia, hypomagnesaemia, hypochloremia, and hypocalcemia.

1. Amphotericin B-Fungizone is used in the care of patients with a. tinea. b. onychomycosis. c. a serious systemic mycotic disease. d. a serious systemic viral disease.

1. (c) Amphotericin B-Fungizone is an antifungal agent.

1. You are to administer the first dose of amphotericin B for a systemic fungal infection. Before beginning the infusion, you should a. administer a test dose. b. assess vital signs. c. administer an antipyretic, such as acetaminophen. d. All of the above e. None of the above

1. (d) Amphotericin may cause infusion reactions. The vital signs should be monitored first to serve as a baseline. A test dose should be given to assess for an infusion reaction. Antipyretics, such as ibuprofen or acetaminophen, are helpful in preventing or minimizing the infusion reaction. Other drugs that might be given are corticosteroids, antihistamines, meperidine, and possibly dantrolene.

1. How do yeasts reproduce?

1. Budding from the parent cell into identical daughter cells

Your patient has a history of chronic heart failure and takes digoxin, hydrochlorothiazide, and captopril for this. The patient recently was treated with prednisone, an oral steroid, for a severe asthmatic attack. Unfortunately, now the patient has experienced a serious Aspergillus infection. The organism is resistant to the usually effective antimicrobials, except for amphotericin B. There are orders to begin amphotericin B therapy. 1. Consider the patient-related variables. Are there any that place this patient at increased risk of adverse effects from the amphotericin? If yes, what are they?

1. The medications digoxin and hydrochlorothiazide, a thiazide diuretic, are both risk factors. The amphotericin B may induce hypokalemia, which increases the risk of digitalis toxicity. The thiazide diuretic also increases potassium loss, so the effect of hypokalemia may be intensifi ed. Again, this places the patient at increased risk of digoxin toxicity and for the adverse effects associated with hypokalemia, such as possibly fatal arrhythmias

1. What factors do you think may contribute to this patient having a serious Aspergillus infection?

1. The oral corticosteroid, prednisone, made this patient immunocompromised. Without the body's normal ability to ward off infection or keep it as a minor infection that could be eradicated, the serious infection of Aspergillus was able to develop.

2. What is the mechanism of action of amphotericin B-Fungizone? a. Alters fungal cell membrane permeability b. Inhibits protein synthesis c. Disrupts fungal mitotic spindle structure d. Interrupts DNA synthesis

2. (a) Altering the fungal cell membrane forms pores or channels and results in increased cell permeability, cell leakage, and death.

2. Patients receiving I.V. amphotericin B-Fungizone have the greatest risk for the development of a. blurred vision. b. arachnoiditis. c. nephrotoxicity. d. hypertension.

2. (c) Nephrotoxicity occurs in more than 80% of patients receiving IV amphotericin B.

2. During the infusion of amphotericin B, your patient experiences wheezing, nausea, and a drop in blood pressure. You should a. increase the rate of infusion. b. change the IV site to a peripheral line with a smaller vein. c. slow the IV rate. d. All of the above e. None of the above

2. (e) This patient is demonstrating signs of infusion reaction. The infusion should be stopped and the physician notified. Increasing the infusion rate would worsen the reaction. Amphotericin B should be administered through a large vein, preferably a central vein because of its irritant properties. Slowing the infusion has not been demonstrated to decrease the infusion reaction.

2. What are hyphae?

2. Long, hollow, and branching fi laments of a mold

2. Should you administer the amphotericin B?

2. Yes, you should give the amphotericin B. Although amphotericin B is not recommended to be given with digoxin or thiazide diuretics, amphotericin B appears to be the only drug of choice to treat an infection that could be fatal. This is the proverbial "rock and a hard place." Because the risk of not receiving the drug could be death, the drug should be given. Monitor very carefully. Nephrotoxicity can easily send this patient into acute CHF. The dose may need to be decreased from a standard dose because of the patient's other pathologies. It is possible that the other drugs could be withdrawn or their dosage is decreased, but this might also precipitate acute CHF.

Your patient has a history of chronic heart failure and takes digoxin, hydrochlorothiazide, and captopril for this. The patient recently was treated with prednisone, an oral steroid, for a severe asthmatic attack. Unfortunately, now the patient has experienced a serious Aspergillus infection. The organism is resistant to the usually effective antimicrobials, except for amphotericin B. There are orders to begin amphotericin B therapy. 2. What can you do to minimize possible adverse effects?

2. You should check the potassium level before and then throughout the therapy. If the patient is hypokalemic before starting therapy, a potassium supplement should be administered. Hydrate as much as possible, but do not push excessive fluids because this may precipitate CHF. Monitor for signs of fluid overload.

3. Your patient is receiving fluconazole prophylaxis against histoplasmosis because of low CD4 and T-cell counts. The patient experiences diarrhea while taking fluconazole. You should a. discontinue use of the fluconazole. b. seek an order for an antidiarrheal. c. obtain stool cultures. d. All of the above. e. None of the above.

3. (b) Diarrhea is common but not a serious adverse effect of fluconazole. The fluconazole therapy should not be discontinued because the patient needs this drug to prevent potentially fatal infections. The diarrhea is not a sign of infection; no culture is needed.

3. Before initiation of amphotericin B-Fungizone therapy, what patient teaching should you do? a. " This infusion may make you feel tired. I'll leave the side rails down." b. " Many patients have a reaction to this medication. I will premedicate you to diminish this possible response." c. " This medication may cause a minor tingling at the IV site. Let me know if that occurs." d. " This infusion will last for about 30 minutes. I'll be back then to take it down."

3. (b) Patients should understand the potential for an infusion reaction so they do not believe they are experiencing an unforeseen event.

3. Which of the following laboratory tests should be done before and throughout amphotericin B-Fungizone therapy? a. CBC b. Electrolytes c. Renal function d. All of the above

3. (d) Amphotericin B-Fungizone affects many body systems, so monitoring these laboratory results is mandatory.

3. In the human host, where would you find an infection with a dermatophyte?

3. Cutaneous level of the body

4. Amphotericin B-Fungizone is thought to have a suppressive effect on erythropoietin production. This may result in a. renal toxicity. b. hepatic toxicity. c. anemia. d. seizure activity.

4. (c) Erythropoietin is necessary for the production of red blood cells. The occurrence of decreased red cells results in anemia.

4. Your female patient is being treated with griseofulvin-Grisactin for a fungal infection in her toenails. The nurse explains that the patient may need to take the medication for 6 to 12 months. Which of the following instructions should also be given to this patient? a. "Keep this medication out of the light." b. "Take this medication with a fatty meal." c. " If you take birth control pills, use another method of contraception." d. " Stop taking the medication 1 week each month."

4. (c) Griseofulvin-Grisactin decreases the effectiveness of birth control pills.

4. You are caring for a patient who has been treated with several antibiotics for a surgical infection after repair of a fractured hip. The patient now has oral candidiasis and is to receive nystatin suspension. To increase the effectiveness of the drug, you should a. shake the suspension and apply to the surgical wound. b. mix the suspension in water and have the patient drink it. c. have the patient swish the suspension in her mouth before swallowing it. d. avoid shaking, draw up in a syringe, and administer to the back of the patient's throat.

4. (c) Swishing the suspension in the mouth will provide topical application of the antifungal to the affected area. The suspension should be shaken, but it should not be applied to the hip wound, mixed with water, or administered to the back of the throat.

4. How is a systemic mycosis different from a dermatophyte?

4. A dermatophyte cannot grow at the body's core temperature. A systemic mycosis is a serious, deep-tissue infection by a fungus capable of growth at the body's core temperature.

5. Your patient is receiving IV fluconazole-Diflucan. What is the appropriate rate of infusion for this medication? a. 200 mg over 20 minutes b. 200 mg per hour c. 200 mg over 3 to 4 hours d. 200 mg IV push over 2 minutes

5. (b) Fluconazole-Diflucan should be administered with an infusion pump at a rate not to exceed 200 mg/hour.

5. Nystatin-Mycostatin, an antifungal drug nearly identical to amphotericin B-Fungizone, is indicated for the treatment of a. severe systemic mycoses. b. oral, cutaneous, mucocutaneous, or vaginal candidiasis. c. severe systemic viruses. d. HIV.

5. (b) Nystatin-Mycostatin is not used for systemic infections because of the risk for toxicity. .

5. Which of the following instructions should the nurse give to the patient receiving posaconazole Noxafil? (Mark all that apply) a. "Take this medication on an empty stomach." b. "Be sure to limit your exposure to the sun." c. " Use the spoon that comes with the medication to take the appropriate amount." d. " Shake the medication before pouring into the spoon." e. " Swallow the capsule whole. Do not open or crush it." f. " Take the medication with food or a nutritional supplement."

5. (c), (d), and (f) Posaconazole-Noxafil is an oral solution. It is important to shake the medication before pouring it into the spoon that is supplied with the medication. It should not be taken on an empty stomach.

6. Your patient has HIV and is being prescribed fluconazole Diflucan for fungal prophylaxis. Your patient also has type 2 diabetes and takes glimepiride-Amaryl. Because of this combination of drugs, you should monitor this patient's a. blood pressure. b. blood glucose. c. kidney function. d. T-cell count.

6. (b) Fluconazole-Diflucan may increase the hypoglycemic effects of sulfonylureas, so it is prudent to monitor blood glucose.

6. Flucytosine--5-FC should be administeredcautiously to patients receiving other medications that are known to induce a. hepatotoxicity. b. nephrotoxicity. c. hematologic toxicity. d. All of the above

6. (d) Flucytosine-5-FC can induce hematotoxicity, nephrotoxicity, and hepatotoxicity, so it should be used cautiously in patients receiving other drugs that may induce these effects.

7. Which of the following drugs is used as primary fungal prophylaxis in immunocompromised patients? a. Fluconazole (Difl ucan) b. Ketoconazole (Nizoral) c. Butenafine (Mentax) d. Amphotericin B (Fungizone)

7. (a) Fluconazole-Diflucan is used for primary fungal prophylaxis in immunocompromised patients with a CD4+ T-cell count of less than 200.

8. The most common adverse effects to fl uconazole-Diflucan therapy affect the _____ system. a. cardiovascular b. gastrointestinal c. reproductive d. endocrine

8. (b) The most common adverse effects of fluconazole-Diflucan are diarrhea, nausea, vomiting, abdominal pain, headache, and dizziness

Amphotericin B, a polyene antifungal Action

Fungicidal or fungistatic that and works by binding to fungal cell membranes, resulting in increased cell permeability, cell leakage, and death. Damage to host cells can also occur.

Amphotericin B, Monitor & Teach

Monitor carefully for nephrotoxicity: intake/output, daily weights to assess for fluid retention. Assess BUN, serum creatinine. Keep the patient well hydrated to minimize effects. Carefully monitor: vital signs, electrolytes, complete blood count, renal function, hepatic function. Educate patients: On the likelihood of a transfusion reaction, other adverse effects.

Amphotericin B, a polyene antifungal Effects

Numerous problems and frequently severe: Nephrotoxicity in 5% to 80% of patients, Infusion-related reactions of headache, chills, fever, rigors, hypotension, bronchospasm, and nausea and vomiting. Electrolyte abnormalities Anemia, Leukopenia Thrombocytopenia, etc. The lipid formulations cause less issues than the traditional formulation; especially nephrotoxicity and infusion reactions

Fungal infections

Range from mildly annoying to life-threatening. Can be systemic or superficial: Systemic infections can cause serious medical problems, especially in patients who are immunocompromised. Classified as opportunistic general: Superficial mycoses can be dermatophytic or mucous membrane related. Most common: Tinea and candidiasis. Two groups: yeasts and molds.

Nystatin

Related to amphotericin B. Uses: Treat topical, vaginal, and oral fungal infections. Not used for systemic infections. Administer: Oral suspension of nystatin should be swished through the mouth and then swallowed or spit out, as directed. Oral troches should be dissolved in the mouth. Adverse effects: Uncommon.

Amphotericin B, Route, Administration, Minimizing Issues

Route: Available only as a parenteral drug for I.V. infusion. Administrations: Give diphenhydramine and acetaminophen before infusion to decrease the risk of infusion reactions. Administer via an in-line filter and IV pump. Minimize issues: Be prepared to administer drug therapy to treat symptoms of infusion reaction. Do a test dose before a full dose to assess the risk of infusion reaction; central line preferred

Amphotericin B, a polyene antifungal Uses

Treats progressive and potentially fatal systemic infections.

fluconazole in pregnancy

Use in pregnancy is somewhat controversial. Extended use during pregnancy can cause development malformations.

Fluconazole, triazole antifungal Uses & Action

Uses: Esophageal, oropharyngeal, and various candida infection, cryptococcal meningitis, and systemic fungal infections. Prophylactic use in immunocompromised patients with a CD4T-cell count less than 200. Action: Wide spectrum activity. Fluconazole works by altering the fungal cell membrane causing permeability and leakage of cell contents. It does not effect human cells. It is available in both oral and intravenous forms.

1. Candida

c . Yeast-like fungus that is almost always present as part of the normal population of organisms in the mouth, skin, intestinal tract, and vagina.

5. tinea

d. Common name for dermatophytic infections

2. cryptococcosis

e. Most serious of the fungal infections in immunocompromised patients

Fluconazole, triazole antifungal Effects & Teaching

most common adverse effects: generally well tolerated but can cause GI issues, headache, dizziness. Mild, temporary elevations in liver enzymes. Can deform the fetus. Teaching: Encourage to avoid alcohol which can increase the risk of liver disease.