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Chapter 42
Antifungal Drugs
Copyright © 2014 by Mosby, an imprint of Elsevier Inc.
Very large and diverse group of microorganisms, including yeasts and molds
Fungal infections also known as mycoses Some fungi are part of the normal flora of the
skin, mouth, intestines, and vagina
Fungi
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Single-cell fungi Reproduce by budding Can be used for
Baking Alcoholic beverages
Yeasts
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Multicellular Characterized by long, branching filaments
called hyphae
Molds
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Four general types Cutaneous Subcutaneous Superficial Systemic
• Can be life threatening
• Usually occur in immunocompromised host
Mycotic Infections
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Candida albicans May follow antibiotic therapy, antineoplastics,
or immunosuppressants (corticosteroids) May result in overgrowth and systemic infections Growth in the mouth is called thrush or oral
candidiasis Common in newborn infants and
immunocompromised patients
Mycotic Infections (cont’d)
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Vaginal candidiasis Yeast infection Pregnancy, women with diabetes mellitus, women
taking oral contraceptives
Mycotic Infections (cont’d)
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Classroom Response Question
A patient has developed an aspergillosis infection. Which tissue does the aspergillosis affect?
A.Skin
B.Nails
C.Blood
D.Lungs
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Drugs used to treat infections caused by fungi Systemic
amphotericin B, caspofungin, fluconazole, voriconazole, terbinafine
Topical nystatin, terbinafine
Antifungal Drugs
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Broken down into major groups based on their chemical structure: Polyenes: amphotericin B and nystatin Imidazoles: ketoconazole Triazoles: fluconazole, itraconazole, voriconazole Echinocandins: caspofungin, micafungin Drugs that are listed individually, not by chemical
structure:• griseofulvin, flucytosine
Antifungal Drugs (cont’d)
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flucytosine Also known as 5-fluorocytosine (antimetabolite) Taken up by fungal cells and interferes with DNA
synthesis Result: fungal cell death Older drug; newer drugs are more commonly used
Mechanism of Action
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griseofulvin Disrupts cell division Result: inhibited fungal mitosis (cell division) Older drug; newer drugs are more commonly used
Mechanism of Action (cont’d)
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Polyenes: amphotericin B and nystatin Bind to sterols in cell membrane lining Result: fungal cell death Do not bind to human cell membranes or kill human
cells
Mechanism of Action (cont’d)
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Imidazoles and triazoles: ketoconazole, fluconazole, itraconazole, voriconazole Inhibit fungal cell cytochrome P-450 enzymes,
resulting in cell membrane leaking Result: altered cellular metabolism and fungal cell
death
Mechanism of Action (cont’d)
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Echinocandins: capsofungin, micafungin, and anidulafungin Prevent the synthesis of glucans (essential
components of fungal cell walls) Result: fungal cell death
Mechanism of Action (cont’d)
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Systemic and topical fungal infections Drug of choice for the treatment of many severe
systemic fungal infections is amphotericin B Choice of drug depends on type and location of
infection
Indications
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Classroom Response Question
A patient is diagnosed with onychomycosis. The nurse anticipates use of which medication for the treatment of this condition?
A.terbinafine (Lamisil)
B.voriconazole (Vfend)
C.fluconazole (Diflucan)
D.amphotericin B (Amphocin, Fungizone)
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Adverse Effects: Amphotericin B
Cardiac dysrhythmias Neurotoxicity; tinnitus; visual disturbances; hand
or feet numbness, tingling, or pain; convulsions Renal toxicity, potassium loss, hypomagnesemia Pulmonary infiltrates Fever, chills, headache, nausea, occasional
hypotension, gastrointestinal upset, anemia
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Classroom Response Question
A patient is receiving amphotericin B lipid complex. The nurse knows that an advantage of the lipid formulations of this drug is that they
A.have a lower cost.
B.can be administered quickly.
C.take longer to be absorbed.
D.cause fewer adverse effects.
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fluconazole Nausea, vomiting, diarrhea, stomach pain, Increased liver enzymes Use with caution in patients with renal and liver
dysfunction nystatin
Nausea, vomiting, anorexia, diarrhea, rash
Antifungal Drugs: Adverse Effects
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Liver failure Renal failure Porphyria (griseofulvin) Drug allergy
Antifungal Drugs: Contraindications
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Many antifungal drugs are metabolized by the cytochrome P-450 enzyme system
Coadministration of two drugs that are metabolized by this system may result in competition for these enzymes, and thus higher levels of one of the drugs
Antifungal Drugs: Interactions
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Before beginning therapy, assess for hypersensitivity, possible contraindications, and conditions that require cautious use
Obtain baseline VS, CBC, liver and renal function studies, and ECG
Assess for other medications used (prescribed and over-the-counter) to avoid drug interactions
Nursing Implications
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Follow manufacturer’s directions carefully for reconstitution and administration
Monitor vital signs of patients receiving IV infusions every 15 to 30 minutes
During IV infusions, monitor I&O to identify adverse effects
Nursing Implications (cont’d)
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Classroom Response QuestionFifteen minutes after an infusion of amphotericin B was started, the patient begins to complain of fever, chills, muscle pain, and nausea. His heart rate has increased slightly, but his blood pressure is down to 100/68. What is the nurse’s priority?
A.Notify the prescriber immediately.
B.Recognize an impending anaphylactic reaction and stop the infusion.
C.Assess for other symptoms of this expected infusion-related reaction.
D.Slow the infusion to reduce these adverse effects.
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amphotericin B To reduce the severity of the infusion-related
reactions, pretreatment with an antipyretic (acetaminophen), antihistamines, antiemetics, and corticosteroids may be given
Use IV infusion pumps and the most distal veins possible
Nursing Implications (cont’d)
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Some oral forms should be given with meals to decrease GI upset; others require an empty stomach—be sure to check
Nursing Implications (cont’d)
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Classroom Response Question
A patient is taking nystatin (Mycostatin) in an oral troche form for oral candidiasis. Which instruction is correct?
A.Allow the troche to dissolve slowly in the mouth.
B.Swish the medication in the mouth and then swallow it.
C.Chew the troche thoroughly to activate the medication.
D.Swallow the troche whole without chewing.
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Nystatin given as an oral lozenge or troche should be slowly and completely dissolved in the mouth (not chewed or swallowed whole)
Nystatin suspension should be swished thoroughly in the mouth as long as possible before swallowing
Nursing Implications (cont’d)
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Monitor for therapeutic effects Easing of symptoms of infection Improved energy levels Normal vital signs, including temperature
Monitor carefully for adverse effects
Nursing Implications (cont’d)
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