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Pharmacology > Antifungal Agents > Flashcards

Antifungal Agents Flashcards

1
Q

Amphotericin A and B are antifungal antibiotics produced by

A

Streptomyces nodosus.

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2
Q

Amphotericin B is an?

A

amphoteric polyene macrolide (polyene =
containing many double bonds; macrolide = containing a large
lactone ring of 12 or more atoms)

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3
Q

Amphotericin B is nearly insoluble in water

and is therefore prepared as a?

A

colloidal suspension of amphotericin B and sodium desoxycholate for intravenous injection

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4
Q

New formulation of Amphotericin B

A

packaged in a lipid-associated delivery system

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5
Q

Most expensive lipid formulation of amphotericin B

A

AmBisome

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6
Q

lipid formulation of amphotericin B with 3 - 5 dosing

A

AmBisome

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7
Q

Lipid formulation of amphotericin B with highest Cmax

A

AmBisome

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8
Q

Lipid formulation of Amphotericin B with infusional toxicity

A

Amphotec

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9
Q

Oral amphotericin B is thus effective only on?

A

fungi within
the lumen of the tract and cannot be used for treatment of systemic
disease because it is poorly absorbed from the GIT

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10
Q

amphotericin B is excreted slowly in the ____ over a period of several days

A

urine

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11
Q

Dose adjustment is required in amphotericin B. True or false?

A

False

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12
Q

How many % of the blood level of amphotericin B is reached in the CSF, necessisating intrathecal therapy for fungal meningitis?

A

2 - 3%

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13
Q

Amphotericin B is selective in its fungicidal effect because?

A

It only targets fungal cell membrane, Ergosterol

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14
Q

Amphotericin B binds to ergosterol and alters the permeability of the cell by forming?

A

amphotericin B-associated pores in the cell membrane

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15
Q

Amphipathic characteristic of Amphotericin B binds with ergosterol along the _____ of its structure and associates with water molecules along the _____

A

double bond-rich side (around outside the pore)

hydroxyl-rich side (lining the inside)

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16
Q

MOA of amphotericin B

A

Formation of pores on the cell membrane bilayer, allowing leakage of intracellular ions and molecules

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17
Q

2 mechanisms of resistance/impairing ergosterol binding by amphotericin B

A
  1. Decreasing the membrane concentration of ergosterol

2. Modifying the sterol target molecule to reduce its affinity for the drug

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18
Q

Antifungal agent with the broadest spectrum of activity.

A

Amphotericin B

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19
Q

With intrinsic amphotericin B resistance

A

Candida lusitaniae and Pseudallescheria boydii

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20
Q

Useful agent for all life-threatening mycotic infections

A

Amphotericin B

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21
Q

Often used as the initial induction regimen to rapidly reduce fungal burden

A

amphotericin B

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22
Q

Used for immunosuppressed patients and those with severe fungal pneumonia, severe cryptococcal meningitis or disseminated infections with endemic mycoses such as histoplasmosis or coccidiodomycosis

A

Amphotericin B

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23
Q

Once initial therapy with amphotericin B is used, what med is used as maintenance therapy?

A

-azoles

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24
Q

For treatment of systemic fungal disease. amphotericin B is given by?

A

Slow IV infusion at 0.5 - 1 mg/kg/day

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25
Q

Amphotericin B is continued to a defined total dose rather than a defined time span. True or false?

A

True

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26
Q

Which remains an option in cases of fungal CNS infections that have not responded to other agents?

A

Intrathecal amphotericin B though it is poorly tolerated and CSF access is difficult

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27
Q

Mycotic corneal ulcers and keratitis may be cured with what kind of amphotericin B formulations/method of administration?

A

topical drops and direct subconjuctival injection

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28
Q

Type of amphotericin B toxicty that manifests as fever, chills, muscle spasms, vomiting, headache, and hypotension

A

Infusion-Related Toxicity

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29
Q

How to treat Infusion-Related Toxicity of amphotericin B?

A

by slowing the infusion rate or

decreasing the daily dose

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30
Q

Premids for amphotericin B

A

antipyretics, antihistamines, meperidine, or corticosteroids

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31
Q

When starting amphotericin B , what should be done to gauge the severity of the reaction?

A

administer a test dose of 1 mg intravenously to serve as a guide to an initial dosing regimen and premedication
strategy

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32
Q

occurs in nearly all patients treated with clinically significant doses of amphotericin

A

Renal damage

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33
Q

A reversible component of amphotericin B renal damage that is associated with a form of prerenal renal
failure

A

decreased renal perfusion

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34
Q

results from renal tubular

injury and subsequent dysfunction in amphotericin B toxicity

A

Irreversible renal damage

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35
Q

The irreversible form of

amphotericin nephrotoxicity usually occurs in the setting of?

A

prolonged administration (> 4 g cumulative dose)

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36
Q

Renal toxicity in amphotericin B use is commonly manifested as?

A

renal tubular acidosis and severe potassium

and magnesium wasting

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37
Q

It is common practice to administer daily doses of amphotericin B with _____ to attenuate prerenal component of cumulative toxicity

A

normal saline infusions

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38
Q

After intrathecal therapy with amphotericin, _____ may develop,
often with serious neurologic sequelae.

A

seizures and a chemical arachnoiditis

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39
Q

Other occasionally seen AEs of amphotericin B

A

Abnormalities of liver function tests

Reduced erythropoietin production
by damaged renal tubular cells

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40
Q

MOA of Flucytosine (5-FC)

A

Inhibition of RNA and DNA synthesis

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41
Q

water-soluble pyrimidine analog related to the

chemotherapeutic agent 5-fluorouracil (5-FU)

A

Flucytosine (5-FC)

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42
Q

Which has a narrower spectrum of activity, 5-FU or amphotericin B?

A

5-FU

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43
Q

5-FU is well absorbed (> 90%), with serum

concentrations peaking ___ after oral dose

A

1–2 hours

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44
Q

5-FU is poorly protein bound. True or false?

A

True

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45
Q

5-FU can penetrate CSF. True or False?

A

True

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46
Q

5-FU is eliminated by?

A

eliminated by glomerular

filtration with a half-life of 3–4 hours and is removed by hemodialysis

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47
Q

5-Fu toxicity is more likely to occur in?

A

AIDS patients

and those with renal insufficiency

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48
Q

Peak serum concentrations of 5-FU
should be measured periodically in patients with renal insufficiency
and maintained between?

A

between 50 and 100 mcg/mL

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49
Q

Flucytosine is taken up by fungal cells via the enzyme?

A

cytosine permease

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50
Q

MOA of flucytosine

A

It is converted intracellularly first to 5-FU and then to
5-fluorodeoxyuridine monophosphate (FdUMP) and fluorouridine
triphosphate (FUTP), which inhibit DNA and RNA synthesis,
respectively

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51
Q

in 5-FU, human cells are unable to convert the

parent drug to its active metabolites, resulting in selective toxicity. True or false?

A

True

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52
Q

5-FC is synergistic with which drug?

A

amphotericin B

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53
Q

Resistance to 5-FU is via?

A

altered metabolism

of flucytosine develops rapidly in monotherapy

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54
Q

The spectrum of activity of flucytosine is restricted to?

A

C neoformans, some Candida sp, and the dematiaceous molds that cause
chromoblastomycosis

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55
Q

Clinical use of 5-FC

A

confined to combination therapy:
+ AmpB = cryptococcal meningitis
+ itraconazole = chromoblastomycosis

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56
Q

The adverse effects of flucytosine result from metabolism

(possibly by intestinal flora) to the toxic antineoplastic compound?

A

fluorouracil

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57
Q

most common adverse effects of flucytosine

A

Bone marrow toxicity with anemia, leukopenia, and thrombocytopenia with
derangement of liver enzymes occurring less frequently; toxic enterocolitis can occur

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58
Q

Azoles are synthetic compounds that can be classified as either
imidazoles or triazoles according to the number of?

A

nitrogen atoms in the five-membered azole ring

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59
Q

Azoles now used only in topical therapy?

A

miconazole, and clotrimazole

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60
Q

The triazoles include?

A

itraconazole, fluconazole, voriconazole, and posaconazol

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61
Q

The antifungal activity of azole drugs results from?

A

the reduction of
ergosterol synthesis by inhibition of fungal cytochrome P450
enzymes

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62
Q

Which has a lesser degree of selectivity accounting for their higher incidence of drug
interactions and adverse effects?

A

Imidazoles vs triazoles

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63
Q

azole drugs with high water solubility

A

Fluconazole

Voriconazole

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64
Q

azole drugs with high variable absorption

A

Ketoconazole

Itraconazole

65
Q

azole drug with highest (>0.7) CSF: Serum

Concentration Ratio

A

Fluconazole

66
Q

azole drug with longest t1/2

A

Itraconazole 24–42 hours

67
Q

Only azole drug excreted renally

A

fluconazole

68
Q

Azole drugs available only in oral forms

A

ketoconazole

Posaconazole

69
Q

The spectrum of action of azole medications is broad, including many species of Candida, C neoformans , the endemic mycoses
(blastomycosis, coccidioidomycosis, histoplasmosis), the dermatophytes,
and, in the case of ____ and ____, even
Aspergillus infections.

A

itraconazole and voriconazole

70
Q

As a group, the azoles are relatively nontoxic. The most common
adverse reaction is relatively?

A

minor gastrointestinal upset

71
Q

All azoles have been reported to cause abnormalities in?

A

liver enzymes and, very rarely, clinical hepatitis

72
Q

First oral azole introduced

A

Ketoconazole

73
Q

It is distinguished from triazoles by its greater propensity to inhibit mammalian cytochrome P450 enzymes

A

Ketoconazole

74
Q

It is available in oral and intravenous formulations and is used at a dosage of 100–400 mg/d.

A

Itraconazole

75
Q

Drug absorption of itraconazole is increased by?

A

food and by low gastric pH

76
Q

An important drug interaction is

reduced bioavailability of itraconazole when taken with?

A

rifamycins

77
Q

Newer formulations of itraconzaole, including an oral liquid and an intravenous preparation,
have utilized ____ as a carrier molecule to enhance solubility
and bioavailability.

A

cyclodextran

78
Q

Azole that penetrates

poorly into the cerebrospinal fluid

A

ketoconazole, itraconazole

79
Q

azole of
choice for treatment of disease due to the dimorphic fungi
Histoplasma, Blastomyces , and Sporothrix.

A

Itraconazole

80
Q

Itraconazole has activity
against Aspergillus sp, but it has been replaced by ____ as
the azole of choice for aspergillosis

A

voriconazole

81
Q

Itraconazole is used extensively in the treatment of?

A

dermatophytoses and onychomycosis

82
Q

Azole that displays a high degree of water solubility and good cerebrospinal fluid penetration.

A

Fluconazole

83
Q

Azole that has the least effect of all the azoles

on hepatic microsomal enzymes.

A

fluconazole

84
Q

Azole that has the widest therapeutic index of the azoles because of fewer hepatic enzyme
interactions and better gastrointestinal tolerance

A

fluconazole

85
Q

Azole available in oral and intravenous formulations and is used at a dosage of
100–800 mg/d.

A

fluconazole

86
Q

azole of choice in the treatment and secondary

prophylaxis of cryptococcal meningitis.

A

Fluconazole

87
Q

has been shown to be equivalent to amphotericin B in
treatment of candidemia in ICU patients with normal white blood
cell counts

A

Fluconazole

88
Q

agent most commonly used for the

treatment of mucocutaneous candidiasis.

A

Fluconazole

89
Q

Fluconazole activity dimorphic fungi is limited to?

A

coccidioidal disease, and in particular for meningitis

90
Q

Fluconazole displays no

activity against?

A

Aspergillus or other filamentous fungi

91
Q

Prophylactic use of fluconazole has been demonstrated to

reduce fungal disease in?

A

bone marrow transplant recipients and AIDS patients

92
Q

Voriconazole is available in intravenous and oral formulations. The recommended dosage is?

A

400 mg/d

93
Q

The azole drug that is well absorbed orally, with a bioavailability exceeding 90%, and it exhibits less
protein binding than itraconazole.

A

Voriconazole

94
Q

A clinically relevant inhibitor of mammalian
CYP3A4, and dose reduction of a number of medications is
required when this is started

A

Voriconazole

95
Q

Drugs affected by voriconazole

A

cyclosporine, tacrolimus, and HMG-CoA reductase inhibitors

96
Q

Observed toxicities in voriconazole use include

A

rash and elevated hepatic enzymes

97
Q

Visual disturbances

are common, occurring in up to 30% of patients receiving?

A

intravenous voriconazole

98
Q

Visual disturbance with intravenous voriconazole include?

A

blurring and changes in

color vision or brightness

99
Q

Visual disturbance with intravenous voriconazole resolve within?

A

30 minutes

100
Q

commonly observed in

patients receiving chronic oral therapy of voriconazole

A

photosensitivity dermatitis

101
Q

Voriconazole is similar to itraconazole in its spectrum of action,
having excellent activity against?

A 
Candida sp (including fluconazoleresistant
species such as Candida krusei ) and the dimorphic fungi
102
Q

is less toxic than amphotericin B and is the treatment

of choice for invasive aspergillosis

A

Voriconazole

103
Q

Azole that is the newest triazole to be licensed in the USA. It is available only in a liquid oral formulation and is used at a dosage of 800 mg/d, divided into two or three doses.

A

Posaconazole

104
Q

Absorption of Posaconazole is improved when taken with?

A

meals high in fat

105
Q

Azole that is rapidly
distributed to the tissues, resulting in high tissue levels but
relatively low blood levels.

A

Posaconazole

106
Q

drug interactions with increased levels of CYP3A4 substrates

such as tacrolimus and cyclosporine have been documented

A

Posaconazole

107
Q

broadest spectrum member of the azole

family, with activity against most species of Candida and Aspergillus

A

Posaconazole

108
Q

It is the only azole with significant activity against the agents of
mucormycosis.

A

Posaconazole

109
Q

currently licensed for salvage therapy in invasive aspergillosis

A

Posaconazole

110
Q

It is currently licensed for prophylaxis of fungal infections during
induction chemotherapy for leukemia

A

Posaconazole

111
Q

It is currently licensed for allogeneic bone

marrow transplant patients with graft-versus-host disease

A

Posaconazole

112
Q 
newest class of antifungal agents to be
developed.
A

Echinocandins

113
Q

They are large cyclic peptides linked to a long-chain fatty acid.

A

Echinocandins

114
Q

These agents are active against Candida and Aspergillus, but not C neoformans or the agents of zygomycosis and mucormycosis.

A

Echinocandins

115
Q

Echinocandins are available only in?

A

intravenous formulations

116
Q

Caspofungin is administered as a single loading dose of?

A

Caspofungin is administered as a single loading dose of 70 mg,
followed by a daily dose of 50 mg.

117
Q

The half-life of caspofungin is __, and the metabolites are excreted by the ____.

A

9–11 hours

kidneys and gastrointestinal tract

118
Q

Dosage adjustments of caspofungin are required only in the presence of?

A

severe hepatic insufficiency

119
Q

Echinocandin that displays similar properties with caspofungin with
a half-life of 11–15 hours and is used at a dose of 150 mg/d for
treatment of esophageal candidiasis

A

Micafungin

120
Q

Micafungin 100 mg/d for treatment of?

A

candidemia

121
Q

Micafungin 50 mg/d is for?

A

prophylaxis of fungal infections

122
Q

Echinocandin that has a half-life of 24–48 hours. For esophageal
candidiasis, it is administered intravenously at 100 mg on the first
day and 50 mg/d thereafter for 14 days.

A

Anidulafungin

123
Q

loading
dose of 200 mg is recommended with 100 mg/d thereafter for at
least 14 days after the last positive blood culture in which echinocandin?

A

Anidulafungin

124
Q

Echinocandins act at the level of the fungal cell wall by?

A

by inhibiting

the synthesis of β(1–3)-glucan

125
Q

currently licensed for disseminated and mucocutaneous

candidal infections

A

caspofungin

126
Q

Echinocandin for empiric antifungal therapy

during febrile neutropenia.

A

Caspofungin

127
Q

largely replaced amphotericin B for the antifungal therapy

during febrile neutropenia

A

Caspofungin

128
Q

Licensed for use
in invasive aspergillosis only as salvage therapy in patients who have
failed to respond to amphotericin B, and not as primary therapy.

A

Caspofungin

129
Q

Licensed for mucocutaneous candidiasis, candidemia,
and prophylaxis of candidal infections in bone marrow transplant
patients

A

Micafungin

130
Q

approved for use in esophageal candidiasis

and invasive candidiasis, including candidemia

A

Anidulafungin

131
Q

Echinocandin agents are extremely well tolerated, with_____ reported infrequently.

A

minor gastrointestinal side effects and flushing

132
Q

Elevated liver enzymes have been noted in several patients receiving caspofungin in combination with?

A

cyclosporine

133
Q

Micafungin has been shown to increase

levels of?

A

nifedipine, cyclosporine, and sirolimus

134
Q

Anidulafungin does not seem to have significant drug interactions, but ____ release may occur during intravenous infusion.

A

histamine

135
Q

a very insoluble fungistatic drug derived from a species of penicillium

A

Griseofulvin

136
Q

Griseofulvin only use is in the systemic treatment of?

A

dermatophytosis

137
Q

It is administered in a microcrystalline form at a dosage of 1 g/d.

A

Griseofulvin

138
Q

Absorption of griseofulvin is improved when?

A

given with fatty foods

139
Q

Griseofulvin’s mechanism of action at the cellular level is unclear, but it is deposited in?

A

deposited in newly forming

skin where it binds to keratin, protecting the skin from new infection

140
Q

Because its action is to prevent infection of these new skin structures, griseofulvin must be administered for?

A

administered for 2–6 weeks for
skin and hair infections to allow the replacement of infected keratin
by the resistant structures

141
Q

Also used for nail infections for months to allow regrowth of the new protected nail and is often followed by relapse

A

Griseofulvin

142
Q

AEs of Griseofulvin

A

allergic syndrome

much like serum sickness, hepatitis

143
Q

Griseofulvin has drug interactions with?

A

warfarin and phenobarbital

144
Q

synthetic allylamine that is available in an oral

formulation and is used at a dosage of 250 mg/d

A

Terbinafine

145
Q

used in the

treatment of dermatophytoses, especially onychomycosis

A

Terbinafine

146
Q

Similarity and difference of griseofulvin with terbinafine

A

Like griseofulvin, terbinafine is a keratophilic medication

Unlike griseofulvin, terbinafine is fungicidal

147
Q

Rather than interacting with the P450 system, terbinafine inhibits the fungal ?enzyme

A

squalene epoxidase

148
Q

One tablet given daily for 12 weeks achieves a cure rate of up to 90% for onychomycosis and is more effective than griseofulvin
or itraconazole.

A

terbinafine

149
Q

AEs of terbinafine

A

gastrointestinal upset and headache

150
Q

A polyene macrolide much like amphotericin B. It is too

toxic for parenteral administration and is only used topically.

A

Nystatin

151
Q

It is not absorbed to a significant degree from skin, mucous membranes,
or the gastrointestinal tract.

A

nystatin

152
Q

As a result, nystatin has little

toxicity, although oral use is often limited by the?

A

unpleasant taste

153
Q

common indications of nystatin include?

A

oropharyngeal thrush, vaginal candidiasis,

and intertriginous candidal infections

154
Q

The two azoles most commonly used topically are?

A

clotrimazole and

miconazole

155
Q

clotrimazole and miconazole are available over-the-counter and are often used for?

A

vulvovaginal

candidiasis

156
Q

Oral clotrimazole troches are available for treatment of oral thrush and are advantageous over nystatin because?

A

it is a pleasant-tasting alternative

157
Q

Useful for dermatophytic
infections, including tinea corporis, tinea pedis, and tinea cruris.
Absorption is negligible, and adverse effects are rare.

A

clotrimazole and

miconazole

158
Q

Allylamines available as topical creams that are effective for treatment of tinea cruris and tinea corporis.

A

terbinafine and naftifine

Pharmacology (8 decks)

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