Exam 3: Antivirals Flashcards Preview

Pharmacology II > Exam 3: Antivirals > Flashcards

Flashcards in Exam 3: Antivirals Deck (56):
1

Describe the mechanisms of Antivirals

1. Alter uncaring of virus
- virus uncoats to begin replication
- drugs prohibit this phase, so cannot penetrate host
2. Polymerase inhibitors
3. Inhibit viral protein synthesis

2

What antiviral drugs are indicated for Influenza A?

amantadine (Symmetril)
rimantidine (Flumadine)

3

Mechanism of amantadine and rimantidine

Blocks uncaring of virus preventing penetration into host
- rimantidine is significantly more active than amantadine

4

Side effects of amantadine and rimantidine

1. CNS stimulation
- enhanced by antihistamines and caffeine
2. Insomnia
3. Grand Mal Seizures

5

Indications for Tamiflu

Influenza A or B

6

What drug is considered the classic prodrug?

Tamiflu
- hydrolyzed to active form

7

Action of Tamiflu

Neuraminidase inhibitor
- drug is an enzyme inhibitor that cleaves the budding viral progeny from its cellular envelope attachment point just prior to release

8

Indications for ribavirin (Rebetol, Virazole)

Treatment of respiratory syncytial virus

9

Mechanism of ribavirin

prevents synthesis of viral proteins encoded by viral mRNA
- inhibits virus RNA polymerase
- Disrupts transcription, translation or promotes degradation of viral RNA

10

Side effects of ribavirin

mutagenic
teratogenic
carcinogenic

11

Indications for trifluridine (Viroptic)

herpes simplex keratitis (in eye)
keratoconjunctivitis

12

Mechanism of trifluridine

interferes with viral replication by incorporating into viral DNA in place of thymidine, causing formation of defective proteins

13

What is the IV drug of choice for HSV encephalitis?

acyclovir (Zovirax)

14

Action of acyclovir (Zovirax)

Inhibits viral DNA polymerase preferentially (Cell cycle specific)

15

Indications for acyclovir

IV drug of choice for HSV encephalitis
- primary and recurrent herpes in immunocompromised patients

16

How often does acyclovir need to be used?

Every 3 hours, which is consistent with cycle phases of viruses

17

Indication of ganciclovir (Cytovene)

human cytomegalovirus (CMV)
- treats CMV retinitis

18

Action of ganciclovir (Cytosine)

inhibits viral DNA synthesis

19

Which drugs are indicated to treat recurrent genital herpes

famciclovir and valacyclovir

20

T or F, famciclovir and valacyclovir are classic prodrugs

true

21

What are interferons?

a family of naturally occurring, inducible glycoproteins that interfere with the ability of viruses to infect cells
- antiviral, cytotoxic, immunomodulatory actions

22

3 types of interferons?

alpha
beta
gamma

23

How are interferons administered?

intralesionally
subcutaneously
IV

24

Mechanism of Interferons

Not completely understood...
- Induction of host cell enzymes that inhibit viral RNA translation, ultimately leading to the degradation of viral mRNA and tRNA

25

Most common indications of Inteferons

Hepatitis B and C
Multiple Sclerosis

- Also used for some cancers

26

Adverse effects of Inteferons

1. Flu-like symptoms
2. bone marrow suppression
3. neurotoxicity
4. CNS effects
5. Severe fatigue
6. Severe weight loss
7. Autoimmune disorders
8. Cardiovascular
9. Oral

27

Name the new drugs for Hepatitis C

1. ledipasvir + sofosbuvir (Harvoni)
2. simeprevir (Olysio)
3. sofosbuvir (Sovaldi)
4. boceprevir (Victrelis)
5. telaprevir (Incivek)

28

What is the challenge with antiretrovirals

To kill the virus, host cells are often harmed
- Antivirals that alter viral replication processes are often toxic to host cells

29

Explain the mechanism of Antiretrovirals

- Inhibiting viral attachment and entry limits spread of virus within body
- Alter genome replication = polymerase inhibitors
- Immunization = provides antibodies against viral envelop proteins

30

Name the drug that was the first antiviral HIV agent that inhibits viral entry into host cells

enfuvirtide (Fuzeon)

31

Target of antiretrovirals for Retrovirsuses?

Reverse transcriptase (1st class to be used)
- main enzyme used by virus to copy genome into DNA

32

3 primary classes of Antiretroviral drugs for HIV

1. Nucleoside reverse transcriptase inhibitors
2. Protease inhibitors
3. Nonnucleoside reverse transcriptase inhibitors

33

What are the drug concepts for HIV?

- Drugs target structural and functional differences between viral and human proteins
- Treatment of HIV infection requires combination therapy = HAART (Highly Active AntiRetroviral Therapy)
- "cocktails"

34

Define a typical cocktail

all of the primary classes of antiretroviral drugs
1. nucleoside reverse transcriptase inhibitor
2. non-nucleoside reverse transcriptase
3. protease inhibitors

35

When are antiretrovirals started in a patient?

when immunosuppression becomes pronounced
- CD4

36

What is a Triple Cocktail?

2 nucleoside reverse transcriptase inhibitors
1 Protease inhibitor

37

Side effects of Antiretrovirals

1. Anemia (toxic to bone marrow and blood cells)
2. Leukopenia and granulocytopenia
3. Hepatotoxicity
4. Peripheral neuropathy
5. Pancreatitis

38

T or F, Nucleoside Reverse transcriptase inhibitors are not classified as prodrugs

False,
Must be biotransformed/bioactivated to work

39

Action of Nucleoside Reverse transcriptase inhibitors

Drug is integrated into DNA polymerase so that synthesis of viral DNA is terminated
- Inhibits viral enzyme reverse transcriptase
- ****Drugs have no effect on cells already containing HIV

40

T or F, Reverse transcriptase of HIV is 1100 times less susceptible to inhibition than are normal human cells making them harder to target

False,
1100 times more susceptible

41

List the Nucleoside reverse transcriptase inhibitors

abacavir (Ziagen)
(B) didanosine (Videx)
emtricitabine (Emtriva)
lamivudine (Epivir)
stavudine (Zerit)
zalcitabine (Hivid)
(B) zidovudine (Retrovir) = AZT

42

Action of AZT

Inhibits HIV synthesis and reduces morbidity/mortality from AIDS and AIDS-related complex

43

Side effects of AZT

1. Very toxic = bone marrow depression
2. CNS effects
3. Nausea
4. Oral effects = altered taste, tongue edema, bleeding gingiva

44

What drugs have interactions that inhibit metabolism of AZT

NSAIDS
Aspirin

45

List the Non-nucleoside reverse transcriptase inhibitors

delavirdine (Rescriptor)
efavirenz (Sustiva)
etravirine (Intelence)
nevirapine (Viramune)

46

Action of Non-nucleoside reverse transcriptase inhibitors

block reverse transcriptase
- Drugs inhibit the catalytic reaction of reverse transcriptase that is independent of nucleotide binding

47

T or F, Non-nucleoside reverse transcriptase inhibitors are classified as prodrugs

false, Do not require bioactivation

48

Action of Protease Inhibitors

Drugs suppress viral replication by inhibiting protease, the enzyme responsible for cleaving viral precursor peptides into infective virions
- Prevents maturation of HIV-infected cells

49

What is the primary difference of protease inhibitors vs the other 2 classes of antiretrovirals

Interfere with the action of HIV-infected cells

50

List the Protease inhibitors

atazanavir (Reyataz)
darunavir (Prezista)
fosamprenavir (Lexiva)
(B) indinavir (Crixivan)
(B) nelfinavir (Viracept)
ritonavir (Norvit)
(B) saquinavir (Invirase)
tipranavir (Aptivus)

51

Action of Nucleotide Reverse transcriptase inhibitors

Interferes with HIV viral RNA dependent DNA polymerase resulting in inhibition of viral replication

52

Name the Nucleotide Reverse Transcriptase inhibitor drug

tenofovir (Viread)

53

Action of Integrase Inhibitors

Inhibits integrase, the enzyme that helps to insert the viral cDNA strand produced by reverse transcriptase into the human genome
- prevents integration of proviral gene into human DNA

54

Name the Integrase Inhibitor drugs

raltegravir (Isentress)
dolutegravir (Tivicay)

55

What is complera

A NEW combination drug used for initial treatment of HIV-infected individuals

56

Complera contains what 3 medications

emtricitabine
rilpivirine
tenofovir disoproxil fumarate