Chapter 40 Antivirals

Question 1

Viruses

Answer 1

• Four routes for entering the body include inhalation, ingestion, transplacentally, and inoculation via mucous membranes or skin
• A competent immune system is the best response to viral infections

Question 2

Antiviral medications

Answer 2

• Controls hepatitis virus, herpes virus (genital and oral herpes), varicella zoster virus (shingles and chicken pox), HIV, influenza virus, respiratory syncytial virus (RSV), and cytomegalovirus (CMV)
• Antiviral medications are used to treat infections caused by viruses other then HIV
• Antiretroviral is used to treat infections caused by HIV

Question 3

Nonretroviral Drugs

Answer 3

• Contraindications include pregnant and lactating women, children younger then 12 months, compromised kidney function, and pre-existing hemoglobinpathies

Question 4

Acyclovir (Zovirax)

Answer 4

• Used to suppress the replication of HSV and VZV
• Drug of choice for initial and recurrent episodes of these infections
• There is a 24-48 hour window for best effects after an outbreak
• Available orally, topically, IV (for immunocompromised)

Question 5

Amantadine

Answer 5

• Only active against influenza A

- Oldest drug. Still used in older adults but not used much anymore

Question 6

Ribavirin (Pegetron, Copegus)

Answer 6

• Given orally or through nasal inhalation

- Inhalation form in used for hospitalized infants with RSV

Question 7

Oseltamivir (Tamiflu) and zanamivir (Relenza)

Answer 7

• Act against influenza A and B
• Oseltamivir causes nausea and vomiting
• Zanamivir causes diarrhea, nausea, and sinustis
• Treatment should begin within 2 days of influenza symptom onset

Question 8

HIV

Answer 8

• ELISA detects HIV exposure based on presence of human antibodies to the virus in the blood
• Four stages of infection (based on CD4 counts)

Question 9

Antiretroviral Drugs

Answer 9

• Includes at least three medications to prevent resistance. These medications work differently to reduce viral load.
• Fusion Inhibitors: inhibit viral fusion, preventing viral replication
• Protease inhibitors (PIs): inhibit the protease retroviral enzyme, preventing viral replication.
  Indinavir sulfate (Crixivan)
• Reverse transcriptase inhibitors (RTIs): block activity of the enzyme reverse transcriptase, preventing production of new viral DNA
  Nucleoside RTIs (NRTIs) - zudovudine (AZT)