Ch. 40: Antiviral drugs

Question 1

Why are viruses called obligate intracellular parasites?

Answer 1

because viruses require a host in order to survive/replicate

Question 2

Explain what is meant by fusion (regarding viruses)

Answer 2

occurs when the virions (DNA or RNA core of a virus) attach to host cells in preparation for infecting the cells

Question 3

What are the 4 routes of entry of viruses?

Answer 3

inhalation through the respiratory tract
ingesting via the GIT
transplacentally from mother to infant
inoculation via skin or mucus membranes

Question 4

Explain the difference between cytopathic effect, viral transformation, and latent infection that result from viral activity in a host cell

Answer 4

cytopathic effect: viral synthesis of nucleic acids and proteins which construct new virus which proceed to infect other cells and this cycle repeats
viral transformation: mutation of the host cell DNA or RNA
latent infection - virions remain inside host cells but do not actively replicate

Question 5

Which of the following are specific immune responses? Non-specific?
phagocytosis
release of cytokines from WBC
antibodies

Answer 5

specific: antibodies

non-specific: phagocytosis and release of cytokines

Question 6

What are the 2 categories of drugs that destroy virions?

Answer 6

disinfectants/virucides

immunoglobulins

Question 7

Why are viral infections more difficult to eradicate?

Answer 7

viruses replicate inside host cells, so antiviral drugs must enter cells in order to disrupt viral replication
viruses replicate rapidly before any symptoms appear

Question 8

What are the mechanisms in which most antiviral drugs work?

Answer 8

interfere with viral nucleic acid synthesis

prevent fusion of virion to host cell

Question 9

What are the 2 major categories of antiviral drugs?

Answer 9

antiviral drugs - for medications used to treat viruses other than HIV
antiretroviral drugs - for treatment of HIV

Question 10

Briefly describe the different herpes viruses.

Which require medications?

Answer 10

HSV-1 = perioral blisters
HSV-2 = genital herpes
HHV-3 = chicken pox and shingles (Varicella zoster virus = VZV)
HHV-4 = Epstein-Barr virus (EBV) - associated with mononucleosis and chronic fatigue syndrome
HHV-5 = cytomegalovirus (CMV)
HHV-6 and 7 not clinically significant but more likely to occur in immunocompromised patients
HHV-8 = Kaposi’s sarcoma herpesvirus - oncogenic virus to cause Kaposi’s sarcoma (AIDS-associated cancer)

Types 3-7 do not require medication except in the case of immunocompromised patients
Types 1-2 are treated with Rx medications

Question 11

How are infants with HSV infections treated?

Answer 11

Cesarean section birth if mother has active genital herpes lesions
IV antivirals for babies born with HSV

Question 12

Explain the relationship between chicken pox (varicella) and shingles (herpes zoster)

Answer 12

both are a result of varicella zoster virus (VZV)
chicken pox infection occurs in childhood –> virus is dormant in nerve ganglia for many years –> re-emerges as shingles in adulthood: painful lesions along dermatome of infected nerve

Question 13

T/F: All active childhood infections of varicella (chicken pox) are treated with antiviral drugs

Answer 13

False: varicella infections are usually self-limiting and do not require antiviral drug therapy except in high risk ie. immunocompromised children

Question 14

What is the risk of first-time varicella zoster virus infection to pregnant women?

Answer 14

VZV is teratogenic, especially during the first trimester

Question 15

What drug is used to treat VZV?

Answer 15

acyclovir, valacyclovir, famciclovir

Question 16

What is the mechanism of action of antiviral drugs?

Answer 16

block the activity of a polymerase enzyme –> catalyzes the synthesis of new viral genomes –> impaired viral replicaton

Question 17

What is an adverse effect specific to Ribavirin?

Answer 17

anemia
therefore, it is CI’d for patients with pre-existing hemoglobinopathies such as sickle-cell anemia, and in patients with autimmune hepatitis

Question 18

What is unique about retroviruses?

Answer 18

Retroviruses are RNA viruses, and use reverse transcriptase enzyme to synthesize DNA from RNA

Question 19

What enzymes are involved in HIV replication?

Answer 19

Reverse transcriptase: synthesis of DNA from RNA

integrase: promotes integration of viral DNA into host cell DNA
protease: separates new viral RNA from viral protein molecules

Question 20

Why is HIV retrovirus so difficult to “cure”?

Answer 20

because the virus is constantly mutating due to high number of errors when transcribing DNA from RNA (backwards process)

Question 21

What are the 3 primary modes of infection with HIV?

Answer 21

sexual, parenteral, perinatal (in utero or during birth)

Question 22

T/F: pregnant women infected with HIV are not given antiretrovirals until after birth because they have teratogenic effects on the fetus

Answer 22

False: prophylactic antiretroviral treatment of infected mothers reduces infection in infants by 2/3 and is not harmful to either mother or infant

Question 23

T/F: Breast milk can transmit HIV to infants in 50% of cases

Answer 23

False: only 10-20% of cases

breastfeeding by infected mothers is CI’d in developed countries, but not in developing countries

Question 24

What are the 4 stages of HIV/AIDS as per the WHO (2005)?

Answer 24

1: Asymptomatic infection
- after initial exposure to the virus, with persistent generalized lymphadenopathy (PGL)
2: early, general symptoms
- continued lymphadenopathy
- fever, rash, sore throat, night sweats, malaise, diarrhea, idiopathic thrombocytopenia, oral candidiasis, herpes zoster
- symptoms may not progress further for 1-10 years
3: moderate symptoms
- continued weight loss, chronic diarrhea, fever
- CD4+ count continues to drop and opportunistic infections begin
4: severe symptoms, often leading to death
= full blown AIDS
- major decline in immune function
- opportunistic infections: pneumocystic jirovecii pneumonia (PCP), CMV, HIV-associated neoplasms e.g. Kaposi’s sarcoma

Question 25

What are some manifestations of HIV wasting syndrome

Answer 25

major weight loss chronic diarrhea more frequent or constant fever chronic fatigue

Question 26

What is meant when a patient is on Antiretroviral therapy (ART)?

Answer 26

a combination of at least 3 antiretroviral drugs to provide suppression of HIV and stop progression of AIDS

Question 27

What are the mechanisms of action of antiretroviral drugs?

Answer 27

``` reverse transcriptase inhibitors (RTIs) block reverse transcriptase protease inhibitors inhibit protease retroviral enzyme --> inhibits breakup of chains of protein molecules fusion inhibitor (enfuvirtide) inhibits viral fusion integrase inhibitor (raltegravir) inhibits integrase - therefore, prevents integration of viral DNA into host cell DNA ```

Question 28

When would a patient who has HIV need to alter his drug regimen?

Answer 28

if patient has major drug intolerance or resistance | if the patient's HIV strain has evolved/mutated and the drug therapy is no longer effective

Question 29

When is the HIV RNA viral load considered to be undetectable?

Answer 29

less than 50 copies/mL

Question 30

What is the effect of ART on HIV patients with concurrent Hepatitis C virus (HCV)?

Answer 30

ART puts pharmacological strain on the liver so patients with both HIV and HCV have increased mortality due to liver disease

Question 31

What is the major adverse effect of protease inhibitors?

Answer 31

lipid abnormalities, including lipodystrophy

Question 32

What is a long-term adverse effect of ART?

Answer 32

bone demineralization --> osteoporosis

Question 33

West Nile Virus (WNV) is transmitted to humans by ___________. WNV can progress to __________ and _____________. Prevention focuses on ___________.

Answer 33

mosquitoes meningitis encephalitis mosquito control strategies

Question 34

SARS is a ______________ virus and usually resolves on its own within _________.

Answer 34

coronavirus | 3-4 weeks

Question 35

Avian influenza can cause human infection, mostly following contact with ____________ or __________________ or ___________________.

Answer 35

infected birds their secretions excrement

Question 36

H1N1 influenza virus is spread via ___________ or ______________.

Answer 36

coughing | sneezing

Question 37

What are important nursing considerations about antivirals in the following forms: oral topical IV

Answer 37

PO: should be given with meals to prevent GI upset topical: should be applied with a finger cot or gloves to prevent autoinoculation IV antivirals should be administered over 1 hour to avoid kidney damage and adequate hydration should be encouraged during and several hours after infusion to prevent drug-related crystalluria

Question 38

What should the nurse do if a patient with HIV has signs and symptoms of opportunistic infections?

Answer 38

Contact the physician immediately

Question 39

Which antivirals are prescribed to prevent/treat influenza A virus? Which antiviral is for treatment of active influenza illness?

Answer 39

For prevention: amantadine oseltamivir (Tamiflu) - for influenza A or B For active illness: zanamivir (Relenza) - for influenza A or B

Question 40

Acyclovir (Zovirax) is used to treat ______ and ________ virus

Answer 40

Herpes (oral and genital) | Varicella - for chicken pox

Question 41

When teaching a patient who is taking acyclovir for genital herpes, which statement by the nurse is accurate? a. acyclovir will eradicate the herpes virus b. this drug will help the lesions to dry and crust over c. this drug will prevent the spread of this virus to others d. acyclovir does not reduce the frequency of genital herpes outbreaks

Answer 41

D

Question 42

A patient who has been newly diagnosed with HIV has many questions about the effectiveness of drug therapy. After a teaching session, which statement by the patient reflects a need for more education? a. there is no cure for HIV b. these drugs will eventually eliminate the virus from my body c. i will be monitored while on this medicine for adverse effects and improvements d. these drugs do not eliminate HIV, but hopefully the amount of virus in my body will be reduced

Answer 42

B

Question 43

During hospitalization for dehydration, an older adult patient is also receiving several doses of amantadine. Which statement explains the rationale for this medication therapy? a. the drug is given IV to treat shingles b. amantadine is used to prevent potential exposure to HIV c. this medication is given prophylactically to prevent influenza A infection d. amantadine works synergistically with antibiotics to reduce superinfections

Answer 43

C