Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Pharmacology > Antifungals/ Antiparasitics > Flashcards

Antifungals/ Antiparasitics Flashcards

1
Q

What is the MOA of amphotericin B/nystatin?

A

binds egosterol and disrupts membrane stability; Forms pores in the membrane; allows leakage of K+; -static or -cidal depending on dose and fungal sensitivity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is the mechanism of selectivity for fungi and resistance charactersitics amphotericin B/nystatin?

A

Affinity for ergosterol is 500X greater than for cholesterol; Resistance is rare but can occur due to decreased ergosterol content

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are the PK prop. of amphotericin B/nystatin?

A

Low solubility and poor oral absorption; conventional formulation given IV in a deoxycholate colloidal suspension
Newer formulations include lipid and liposomal complexes, colloidal suspensions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are the uses for amphotericin B?

A

broad spectrum agent used for life-threatening systemic mycoses (boxed warning)
Initial induction regimen to rapidly reduce fungal burden, then replaced by an azole

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are the uses for Nystatin?

A

oral/topical for cutaneous, vaginal, mucosal, esophageal candidiasis; “swish and swallow”

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are the adverse reactions of amphotericin B?

A

Infusion-related effects, Renal toxicity, hematologic toxicity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are the characteristics of infusion related effects to amphotericin B?

A

cytokine storm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are the characteristics of renal toxicity to amphotericin B?

A

Vasoconstriction of renal afferent arterioles

Proximal tubular cell injury – hypokalemia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are the characteristics of hematologic toxicity to amphotericin B?

A

myelosuppression resulting in anemia; thought to be due to decreased erythropoietin secretion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

How can toxicity to kidneys and infusion reaction to amphotericin B be decreased?

A

Lipid-based formulations are less toxic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is the MOA of flucytosine?

A

Active transport by cytosine permease; Converted to 5-FU by cytosine deaminase; 5-FU converted to 5-FdUMP, a potent inhibitor of thymidylate synthase; Fungistatic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

How does resistance develop to flucytosine?

A

develops during monotherapy; due to mutations of permease and deaminase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What are the uses of flucytosine?

A

Narrow spectrum agent used to treat systemic candidiasis, Cryptococcus neoformans infections; Usually administered in combination with amphotericin B; synergistic effect is due to enhanced uptake of flucytosine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are the PK prop of flucytosine?

A

orally absorbed and well distributed; dose reduction is necessary in renal insufficiency

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are the adverse reactions to flucytosine?

A

Hematologic – conversion to 5-FU by GI flora

Hepatoxicity – mild, reversible

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are the drug interactions with flucytosine?

A

Amphotericin B

Drugs that cause hematological toxicities

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is the MOA of griseofulvin?

A

binds tubulin, disrupting assembly of the mitotic spindle
Accumulates in keratin precursor cells
Allows new growth of skin, hair or nails to be free of fungal infection
Not active against Candida and is not useful in systemic mycoses

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What are the uses of griseofulvin?

A

Administered orally to treat dermatophytic infections of hair, skin and nails
First-line agent for many years but has been replaced by allylamines and azoles
Commonly used in children for scalp ringworm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What are the adverse reactions of griseofulvin?

A

Headaches
Can precipitate attacks of acute intermittent porphyria in susceptible patients
Photosensitivity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is the MOA of terbinafine?

A

inhibits squalene epoxidase
Prevents conversion of squalene to lanosterol
Causes accumulation of squalene, which is cytotoxic; action is fungicidal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What are the uses of terbinafine?

A

Topical use for ringworm infections caused by dermatophytes; less active against Candida species
Oral use for treatment of onychomycosis of toe- and fingernails; topical formulations cannot penetrate deeply enough into the cuticle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What are the adverse reactions to terbinafine

A

generally well tolerated orally
Drug interactions (2D6, 3A4)
Skin reactions
Disturbances of taste; Hepatotoxicity – fatalities have occurred but are rare; contraindicated in patients with liver disease

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What is the MOA of azoles like fluconazole?

A

inhibit 14a-sterol demethylase
Prevents conversion of lanosterol to ergosterol
Causes destabilization of cell membrane and associated enzymes, and increased membrane permeability; action is fungistatic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What are the selectivity features of azoles like fluconazole?

A

Selectivity results from their greater affinity for fungal than for human CYPs
Triazoles are more selective than imidazoles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

How should azoles susceptibility determined?

A

Sanford guide

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What are the uses for azoles like fluconazole?

A

used topically or orally; active against many pathogenic fungi
Systemic mycoses – fluconazole for cryptococcal meningitis
Superficial mycoses including dermatophytes and Candida yeast infections
Vaginal yeast infections
Onychomycosis – topical (elfinaconazole)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What drugs are used for Bacterial vaginosis (Gardnerella vaginalis)?

A

metronidazole, clindamycin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What drugs are used for Candidal vulvovaginitis (Candida albicans)?

A

azoles

29
Q

What drugs are used for Trichomoniasis (Trichomonas vaginitis)?

A

metronidazole, tinidazole

30
Q

What adverse reactions are associated with azoles like fluconazole?

A

Most common is GI upset
Drug interactions – due to inhibition of human CYPs; can result in serious toxicity
Hepatotoxicity
Avoid during pregnancy

31
Q

What is the prototype for a Newer class of agents called echinocandins that are semi-synthetic lipopeptides?

A

caspofungin

32
Q

What is the MOA of caspofungin?

A

non-competitive inhibitors of b-(1,3)-D-glucan synthesis; action is fungicidal

33
Q

What are the uses of caspofungin?

A

IV therapy of invasive aspergillosis
Persistent febrile neutropenia
Systemic candidiasis

34
Q

What are the five types of malaria?

A

Plasmodium infect humans – falciparum, vivax, ovale, malariae, knowlesi; 300-500 million cases and 1 million deaths per year

35
Q

What are the features of falciparum malaria?

A

most common and severe form; many strains are drug resistant; cerebral form of malaria is often lethal; 1400 per year in US

36
Q

What are the features of vivax malaria?

A

milder but common form of malaria; can relapse due to dormant hypnozoites that remain in the liver; not affected by blood-stage antimalarials

37
Q

What are the features of knowlesi malaria?

A

recently-recognized zoonotic infection found in Southeast Asia

38
Q

What are the drugs used for prophylaxis of malaria?

A

chloroquine and primaquine

39
Q

What are the drugs used for treatment of active or latent infection?

A

artemether/lumefantrine, chloroquine, and primaquine

40
Q

What drugs are used to produce a clinical cure for the blood stage?

A

chloroquine and artemisinins

41
Q

What drug is used to prodce the radical cure of relapsing (vivax, ovale) malaria?

A

primaquine

42
Q

What two agents have significant gametocidal activity; no individual clinical benefit but this property disrupts disease transmission?

A

artemether and primaquine

43
Q

Prophylactic agents must have what properties?

A

orally effective with long half-lives and low toxicity

44
Q

What is the MOA of chloroquine?

A

Weak base becomes trapped in food vacuole
Digestion of hemoglobin liberates heme; parasite biocrystallizes heme to insoluble hemozoin
Chloroquine inhibits biocrystallization
Resistance due to mutated PfCRT

45
Q

What are the uses of chloroquine?

A

clinical cure and prophylaxis against sensitive strains
Ineffective against most strains of P. falciparum in Africa, Asia and S. America
Prophylaxis and treatment during pregnancy

46
Q

What are the adverse reactions to cholorquine?

A

Generally well tolerated in doses used for prophylaxis

In doses for clinical cure, can cause pruritis, headache and GI effects; high dose can provoke cardiovascular toxicity

47
Q

What is artemether, MOA and PK properties?

A

Derived from the medicinal Chinese plant qinghao; MOA– unclear; formation of toxic free radicals; PK– rapid absorption and short half-life; not useful for prophylaxis

48
Q

What are the uses of artemether?

A

Fixed-dose combination with lumefantrine (Coartem®); this long-acting “partner drug” sustains antimalarial activity
First-line oral treatment of MDR falciparum malaria in many endemic areas
IV artesunate has replaced quinidine for severe malaria
Inactive counterfeits are common

49
Q

What are the uses of primaquine?

A

With chloroquine to achieve cure of vivax/ovale malaria
Terminal prophylaxis after completion of travel to endemic areas
Primary prophylaxis against all species

50
Q

What are the adverse reactions to primaquine?

A

Generally well tolerated in G6PD-normal patients but may cause mild cyanosis
Prototype for drug-induced hemolytic anemia in G6PD deficiency
Contraindicated in all G6PD-deficient patients and in pregnant females in endemic regions because G6PD status of the fetus is unknown

51
Q

What are Common Protozoal Infections in U.S.?

A

Trichmoniasis, giardiasis and amebiasis
The principal site of amebiasis infection is the GI; infection can be asymptomatic, mild to moderate, or severe
Classification is systemic or luminal

52
Q

What is the MOA of metronidazole?

A

prodrug converted to DNA-damaging metabolite in anaerobes

53
Q

What are the uses of metronidazole?

A

For amebiasis; given in combination with a luminal amebicide

54
Q

What is the MOA of paromycin?

A

– aminoglycoside; not absorbed from the GI tract

55
Q

What are the uses of paromycin?

A

Alone for asymptomatic amebiasis or in combination for amebic colitis/dysentery
Alternative to metronidazole in pregnancy

56
Q

What are the adverse reactions to paromycin?

A

GI distress

57
Q

What is the MOA of albendazole?

A

Inhibits polymerization of parasite ß-tubulin
Disrupts nematode motility and DNA replication
First-pass metabolism to sulfoxide

58
Q

What are the uses of albednazole?

A

Cestode infections – neurocysticercosis and hydatid disease
Roundworm infections – ascariasis, hookworm, toxocariasis
Pinworm infection (enterobiasis) – single 400 mg dose repeated 2 weeks later

59
Q

What are the adverse reactions to albednazole?

A

Teratogenic effects in animals; use should be avoided during pregnancy
Long term use can cause liver toxicity; liver function tests are needed

60
Q

What is the MOA of praziquantel?

A

increases the permeability of cell membranes to Ca2+; results in paralysis, dislodgement and death

61
Q

What are the uses of praziquantel?

A

schistosomiasis, trematode and cestode infections; alternative to albendazole for cysticercosis

62
Q

What are the adverse reactions to praziquantel?

A

generally well tolerated; not clear whether symptoms are drug-related or due to release of proteins from dying worms

63
Q

What is the MOA of pyrantel pamoate?

A

depolarizing neuromuscular blocker
Effective only within the GI tract
Causes persistent activation of N-ACh receptors and inhibition of AChE; results in spastic paralysis followed by expulsion

64
Q

What are the uses for pyrantel pamoate?

A

OTC; Alternative to albendazole for ascariasis and enterobiasis

65
Q

What are the adverse reactions to pyrantel pamoate?

A

generally well tolerated; will produce neuromuscular blockade if given parenterally

66
Q

What is the MOA to Ivermectin?

A

immobilization by tonic paralysis
Activates glutamate-gated Cl– channels
Causes hyperpolarization of the cell membrane
P-glycoprotein keeps drug out of CNS

67
Q

What are the uses for Ivermectin?

A

Broad spectrum agent used to treat infections by nematodes and arthropods in veterinary medicine
Onchocerciasis, lymphatic filariasis and intestinal nematodes in humans

68
Q

What are the adverse reactions to Ivermectin?

A

Mazzotti reaction – in onchocerciasis; pruritis, rash, fever and lymphedema; due to immune reaction to dying worms
Teratogenic (cleft palate) in animal studies; should be avoided during pregnancy

Pharmacology (8 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions