Chapter 42
Antifungal Drugs
Fungi
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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.
Systemic, cutaneous, subcutaneous, and
superficial
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Fungi (Cont.)
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Cutaneous, subcutaneous, and superficial:
infections of various layers of the integumentary
system (skin, hair, or nails)
Fungi that cause integumentary infections are
known as dermatophytes.
Dermatomycoses
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Yeasts
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Single-cell fungi
Reproduce by budding
Can be used for:
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Baking
Alcoholic beverages
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Molds
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Multicellular
Characterized by long, branching filaments
called hyphae
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Mycotic Infections
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Four general types:
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Cutaneous
Subcutaneous
Superficial
Systemic
• Can be life threatening
• Usually occur in immunocompromised host
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Mycotic Infections (Cont.)
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Candida albicans
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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
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Mycotic Infections (Cont.)
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Vaginal candidiasis
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Yeast infection
Pregnancy, women with diabetes mellitus, women
taking oral contraceptives
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Audience Response System
Question #1
A patient has developed an aspergillosis infection.
Which tissue does the aspergillosis affect?
A.
B.
C.
D.
Skin
Nails
Blood
Lungs
NOTE: No input is required to proceed.
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Answer to System Question #1
ANS: D
The primary tissue affected by aspergillosis is the
lungs.
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Antifungal Drugs
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Drugs used to treat infections caused by fungi
Systemic
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Amphotericin B, caspofungin, fluconazole, flucytosine,
griseofulvin, itraconazole, ketoconazole, micafungin,
nystatin, terbinafine, isavuconazonium, anidulafungin,
and voriconazole
Topical
Ophthalmic: natamycin
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Antifungal Drugs (Cont.)
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Broken down into major groups based
on their chemical structure
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Triazoles: fluconazole, itraconazole, voriconazole,
others
Echinocandins: caspofungin, micafungin,
anidulafungin
Imidazoles: ketaconazole
Polyenes: amphotericin B formulations, nystatin
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Mechanism of Action
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Polyenes: amphotericin B and nystatin
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Bind to sterols in cell membrane lining
Result: fungal cell death
Do not bind to human cell membranes or kill human
cells
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Mechanism of Action (Cont.)
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Imidazoles and triazoles: ketoconazole,
fluconazole, itraconazole, voriconazole
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Inhibit fungal cell cytochrome P-450 enzymes,
resulting in cell membrane leaking
Result: altered cellular metabolism and fungal cell
death
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Mechanism of Action (Cont.)
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Echinocandins: caspofungin, micafungin, and
anidulafungin
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Prevent the synthesis of glucans (essential
components of fungal cell walls)
Result: fungal cell death
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Indications
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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
Fluconazole: passes into the cerebrospinal fluid
and inhibit the growth of cryptococcal fungi,
effective in the treatment of cryptococcal
meningitis
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Audience Response System
Question #2
A patient is diagnosed with onychomycosis. The
nurse anticipates use of which medication for the
treatment of this condition?
A. Terbinafine
B. Voriconazole
C. Fluconazole
D. Amphotericin B
NOTE: No input is required to proceed.
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Answer to System Question #2
ANS: A
Terbinafine (Lamisil) is indicated for the treatment of
onychomycosis (fungal infection of fingernail or toenail).
Voriconazole (Vfend) is indicated for the treatment of invasive
aspergillosis and other major fungal infections in patients who do
not tolerate or respond to other antifungal drugs. Fluconazole
(Diflucan) is indicated for the treatment of vaginal candidiasis,
oropharyngeal and esophageal candidiasis, systemic
candidiasis, and cryptococcal meningitis. Amphotericin B
(Amphocin, Fungizone) is indicated for the treatment of systemic
infections with broad spectrum of fungi.
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Antifungal Drugs: Contraindications
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Most common: drug allergy, liver failure, kidney
failure, and porphyria (for griseofulvin)
Itraconazole: contraindicated treatment of
onychomycoses in patients with severe cardiac
problems
Voriconazole can cause fetal harm in pregnant
women.
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Amphotericin B: Adverse Effects
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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 (GI) upset, anemia
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Amphotericin B: Adverse Effects:
Prevention
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Prescribers commonly order various
premedications: antiemetics, antihistamines,
antipyretics, and corticosteroids.
Prevent or minimize infusion-related reactions to
amphotericin B
Likelihood of such reactions can also be
reduced by using longer-than-average drug
infusion times (i.e., 2 to 6 hours).
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Audience Response System
Question #3
A patient is receiving amphotericin B lipid complex.
The nurse knows which as an advantage of the lipid
formulations of this drug?
A.
B.
C.
D.
They have a lower cost.
They can be administered quickly.
They take longer to be absorbed.
They cause fewer adverse effects.
NOTE: No input is required to proceed.
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Answer to System Question #3
ANS: D
Lipid formulations of amphotericin B have been developed
in an attempt to decrease the incidence of its adverse
effects and increase its efficacy. There are currently three
lipid preparations of amphotericin B: (1) amphotericin B
lipid complex (Abelcet), (2) amphotericin B cholesteryl
complex (Amphotec), and (3) liposomal amphotericin B
(AmBisome). These lipid dosage forms have a much higher
cost than conventional amphotericin B and for this reason
are often used only when patients are intolerant of or have
an infection refractory to nonlipid amphotericin B.
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Antifungal Drugs: Adverse Effects
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Fluconazole
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Nausea, vomiting, diarrhea, stomach pain
Increased liver enzymes
Use with caution in patients with renal and liver
dysfunction
Nystatin
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Nausea, vomiting, anorexia, diarrhea, rash
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Antifungal Drugs: Contraindications
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Liver failure
Renal failure
Porphyria (griseofulvin)
Drug allergy
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Antifungal Drugs: Interactions
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Many antifungal drugs are metabolized by the
cytochrome P-450 enzyme system.
Co-administration 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.
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Nursing Implications
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Before beginning therapy, assess for
hypersensitivity, possible contraindications, and
conditions that require cautious use.
Obtain baseline vital signs, complete blood
count, liver and renal function studies, and
electrocardiography.
Assess for other medications used (prescribed
and over the counter) to avoid drug interactions.
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Nursing Implications (Cont.)
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Follow the manufacturer’s directions carefully for
reconstitution and administration.
Monitor vital signs of patients receiving
intravenous (IV) infusions every 15 to 30
minutes.
During IV infusions, monitor input and output to
identify adverse effects.
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Audience Response System
Question #4
Fifteen 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 mm Hg. 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.
NOTE: No input is required to proceed.
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Answer to System Question #4
ANS: C
Almost all patients who receive amphotericin B
experience fever, chills, hypotension, tachycardia,
malaise, muscle and joint pain, anorexia, nausea
and vomiting, and headache. For this reason,
antihistamines, acetaminophen (an antipyretic),
and antiemetics may be given as pretreatment to
reduce these expected effects.
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Nursing Implications
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Amphotericin B
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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.
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Nursing Implications (Cont.)
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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.
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Audience Response System
Question #5
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.
NOTE: No input is required to proceed.
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Answer to System Question #5
ANS: A
Oral troche or lozenge forms of this medication
should be allowed to dissolve slowly in the mouth
without chewing.
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Nursing Implications
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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.
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Nursing Implications (Cont.)
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Monitor for therapeutic effects.
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Easing of symptoms of infection
Improved energy levels
Normal vital signs, including temperature
Monitor carefully for adverse effects.
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