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Pharmacology Test #2 > Antiviral Drugs > Flashcards

Antiviral Drugs Flashcards

1
Q

The most severe constraint limiting the use of antiviral drugs?

A

not the lack of efficacy but the toxicity to the mammalian cell (poor selective toxicity)

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2
Q

Virus specific enzymes

A

proteases, mRNA capping enzyme, neuraminidases, ribonucleases, kinases, integrases and uncoating enzymes

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3
Q

In the case of antivirals, the therapeutic window is

A

the ratio of the minimum dose that is toxic to host cells over the minimum dose that is toxic to the virus

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4
Q

What is required to maintain the suppression of many viral infections

A

an intact immune system (because antiviral drugs available so far are virostatic)

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5
Q

Three subclasses of drugs that prevent viral entry into host cells

A
  1. inhibitors of attachment that compete with a viral receptor
  2. coreceptor antagonists
  3. fusion inhibitors that prevent fusion with host cells
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6
Q

Maraviroc

A

CCR5 coreceptor antagonist - tested for AIDS treatment

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7
Q

what kind of patients should maraviroc be used in

A

CCR5-tropic patients (M-tropic)

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8
Q

When should maraviroc dose be adjusted

A

if used with drugs that inhibit or stimulate cytochrome P450 CYPA3 enzyme to adjust for changes in its metabolism

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9
Q

cenicriviroc

A

dual CCR5 and CCR2 antagonist

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10
Q

PRO 140

A

a CCR5 monoclonal antibody

for treatment experienced patients

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11
Q

Enfuvirtide (T-20)

A

fusion inhibitor
derived from the natural gp41 HR2 sequence
first HIV fusion inhibitor acting by specifically inhibiting the function of the gp41 transmembrane glycoprotein of HIV-1

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12
Q

Virus uncoating corresponds to

A

loss of viral protein coat (nucleocapsid proteins in nonenveloped viruses) or fusion of viral lipid memebranes (loss of lipid envelope in membrane containing viruses) with an endosome/lysosome

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13
Q

good target for therapy by interfering with pH?

A

endosome/lysosome compartment

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14
Q

Arildone

A

inhibits uncoating of picornaviruses that do not have a lipid membrane by blocking ion transport; drug inserts into a canyon in the VP1 viral proteins and blocks ion transport

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15
Q

What happens when you inhibit viral integrase?

A

prevent the insertion of the virus genetic code into the DNA of infected cells

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16
Q

Integrase inhibitors

A

Raltegravir (1st one)

elvitegravir, dolutegravir ect.

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17
Q

targets of drugs that act on the duplication of the viral genome

A

polymerases

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18
Q

nucleoside analog drugs

A

idoxuridine, cytarabine, vidarabine, ribavirin, acyclovir, ganciclovir, azidothimidine

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19
Q

Drugs that act on polyadenylation, methylation, capping, and splicing of viral RNA

A

ribavirin, interferon

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20
Q

Ribavirin inhibits

A

replication of DNA and RNA viruses including influenza A and B, RSV, hepatitis C, HIV

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21
Q

Ribozymes are

A

RNA molecules that induce specifically the cleavage of nucleic acids

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22
Q

Nonspecific drug that inhibits protein translation

A

interferon

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23
Q

What does neuraminidase or sialidase do?

A

helps spread the influenza virus from cell to cell by removing sialic acid from the surface of infected cells so that viral particles may escape

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24
Q

zanamivir is a potent inhibitor of

A

viral neuraminidase of type A and B influenza viruses

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25
Q

zanamivir acts as

A

a sialic acid analog inhibitor

highly specific for influenza viral neuraminidase and has little activity against mammalian/bacterial neuraminidases

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26
Q

Zanamivir requires

A

aerosol delivery to the respiratory tract

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27
Q

Oseltamivir

A

carbocyclic sialic acid analogue

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28
Q

Examples of drugs that interfere with the assembly of the molecular components into the whole virus

A

protease inhibitors

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29
Q

Examples of protease inhibitors

A

aquinavir, ritonavir, indinavir, nelfinavir, amprenavir, lopinavir, atazanavir, fosamprenavir, tipranavir, darunavir, asunaprevir

30
Q

Amantadine inhibits

A

uncoating of the viral RNA of influenza A
may act on the maturation stage of the virus in the trans-golfi network
acts on the maturation of influenza HA glycoprotein

31
Q

Uses of Amantadine

A

oral prophylaxes against influenza A (not used much)

32
Q

Side effects to Amandatine

A

GI intolerance and CNS complains (nervousness, difficulty concentrating)

33
Q

Other drug related to amantadine

A

rimantadine

34
Q

Idoxuridine is a pyrimidine analog that

A

inhibits viral DNA synthesis after activation by phosphorylation (by thymidine kinase)

35
Q

idoxuridine is primarily active against

A

herpes and pox viruses

36
Q

why is idoxuridine too toxic for systemic use?

A

lacks specificity: inhibits host DNA polymerase as well as the viral enzyme

37
Q

What is idoxuridine used for?

A

topically for epithelial herpetic keratitis (mainly been replaced by other drugs)

38
Q

What kind of drugs are cytarabine and vidarabine?

A

nucleoside analogs of cytosine and adeneine respectively

39
Q

Ribavirin is a triazole purine nucleoside analog that inhibits

A

the replication of a wide range of RNA and DNA viruses in vitro
may act as a guanoside analog and inhibit 5’ cap formation on mRNA

40
Q

Ribavirin used to treat

A

RSV in children
parainfluenza virus infections
IV against Lassa fever and other hemorrhagic fevers
orally to treat hepatitis C w interferon alpha

41
Q

toxicity of ribavirin

A

high, notably dose-dependent hemolytic anemia

also mutagenic and teratogenic

42
Q

Acyclovir

A

best example of multiple selectivity
very selective and one of the better antivirals
wide safety margins

43
Q

Acyclovir is nontoxic to

A

noninfected cells (except for the kidney system since it induces renal dysfunction) because it is not activated by these cells

44
Q

Acyclovir is what type of analog

A

purine analog that competes with dGTP

45
Q

How does acyclovir block DNA synthesis

A

can block DNA synthesis by binding to the active site of DNA polymerase and inhibiting this enzyme

46
Q

Triphosphate acyclovir also acts as a

A

chain terminator

47
Q

Dosage adjustments of acyclovir required in case of

A

renal impairment (more than 70% of drug is excreted unchanged in urine)

48
Q

resistant viral strains appear with acyclovir that result from

A

changes in the kinase or polymerase gene

49
Q

Uses for acyclovir

A 
HSV keratitis
Varicella-Zoster virus
latent HSV
fever blisters
genital herpes
EBV/CMV
50
Q

Drugs used to treat herpes simplex

A

acyclovir
valacyclovir
famciclovir
combination of acyclovir and hydrocortisone

51
Q

Ganciclovir is very similar to

A

acyclovir

52
Q

Uses of ganciclovir

A

restricted to life- or sight-threatening CMV infections in AIDS patients

53
Q

Azidothymidine or zidovudine (AZT)

A

chain terminator

54
Q

What accounts for the specificity of AZT?

A

reverse transcriptase is more sensitive to the drug than DNA-dependent DNA polymerase

55
Q

AZT activity is enhanced by

A

acyclovir and interferon

56
Q

AZT is very active against

A

mammalian retroviruses

HIV treatment

57
Q

Side effects of AZT

A 
mainly hematologic (granulocytopenia and anemia)
some GI disturbance, paresthesia, skin rash, fever, abnormal liver function, myopathy
58
Q

lamivurdine is very effect against

A

HBV

59
Q

Adevofir is an analog of

A

adenosine monophosphate, competitively inhibits HBV DNA polymerase

60
Q

Eight nucleoside reverse transcriptase inhibitors (NRTIs)

A

zidovudine, didanosine, zalcitabine, stavudine, lamivudine, abacavir, emtricitabine, tenofovir

61
Q

Nucleotide reverse transcriptase inhibitor (NtRTI)

A

tenofovir, sofosbuvir

62
Q

five non-nucleoside reverse transcriptase inhibitors (NNRTIs)

A

nevirapine, delavirdine, efavirenz, etravirine, and rilpivirine

63
Q

Adenosine arabinosine

A

severe side effects and only used in potentially lethal diseases

64
Q

Foscarnet (phosphonoformic acid)

A

competitive inhibitor of DNA polymerase that binds to pyrophosphate sites
also an inhibitor of RNA polymerase and HIV reverse transcriptase

65
Q

Saquinavir

A

first protease inhibitor licensed for HIV therapy

used with ritonavir

66
Q

Indinavir

A

reduces HIV load so that PCR can’t detect virus when used in combination therapy
intolerable side effects

67
Q

Telapreir has been FDA approved to treat

A

Hepatitis C infection

68
Q

Three classes of interferons

A

alpha, beta, gamma

69
Q

what do alpha and beta interferons do

A 
cytokines that bind to specific receptors on adjacent cells and protect them from viral infection
also enhance the expression of class I and class II MHC
70
Q

gamma interferon

A

cytokine secreted by T lymphocytes that enhances specific T cell mediated immune response

71
Q

Side effects of interferons

A

fever, myalgia, bone marrow suppression, neurotoxicity

72
Q

Pre-exposure prophylaxis for HIV

A

Truvada

Pharmacology Test #2 (13 decks)

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