252 Pharmacology Antiviral Drugs

Question 1

What is a major difference between viruses and bacteria?

Answer 1

A virus must replicate within the cells of its host.

Question 2

Where and how does a virus replicate?

Answer 2

A virus cannot replicate on its own.
It must attach to and enter a host cell.
It then uses the host cell’s energy to synthesize protein, deoxyribonucleic acid (DNA), and ribonucleic acid (RNA).

Question 3

Why are viruses difficult to kill?

Answer 3

• Viruses are difficult to kill because they live inside the cells.
• Any drug that kills viruses may also kill cells.

Question 4

What is the general mode of action of antiviral drugs?

Answer 4

• Kill or suppress the virus by destroying virions or inhibiting the ability of viruses to replicate; controlled by current antiviral therapy
• Immunoglobulins: concentrated antibodies that can attack and destroy viruses

Question 5

What viruses are controlled by current antiviral therapy?

Answer 5

• Cytomegalovirus (CMV)
• Hepatitis viruses
• Herpesviruses
• HIV
• Influenza viruses (“flu”)
• Respiratory syncytial virus (RSV)

Question 6

What are the key characteristics about antiviral drugs and their mechanisms of action?

Answer 6

• Able to enter the cells that are infected with virus
• Interfere with viral nucleic acid synthesis or regulation or both
• Prevent the fusion process
• Some stimulate the body’s immune system.

Question 7

Patients with what feature have the best response to antivirals?

Answer 7

Those with competent immune systems.

Question 8

What is an opportunistic infection?

Answer 8

• Occur in immunocompromised patients
• Would not normally harm an immunocompetent person
• Require long-term prophylaxis and anti-infective drug therapy
• Can be other viruses, fungi, bacteria, or protozoa

Question 9

What is the difference between antiviral drugs and antiretroviral drugs?

Answer 9

Antiviral drugs are used to treat infections caused by viruses other than HIV while antiretroviral drugs are used to treat infections caused by HIV, the virus that causes AIDS.

Question 10

HSV-1

Answer 10

oral herpes

Question 11

HSV-2

Answer 11

genital herpes

Question 12

HHV 3 (aka VZV)

Answer 12

human herpes virus/varicella-zoster virus

Question 13

HHV4

Answer 13

Epstein-Barr virus

Question 14

HHV 5

Answer 14

CMV

Question 15

HHV 6 and HHV 7

Answer 15

no clinically significant; mostly in immunocompromised patients

Question 16

HHV 8

Answer 16

Karposi’s sarcoma

Question 17

What drug is used to treat shingles?

Answer 17

acyclovir; best when started within 72 hours of symptom onset

Question 18

What are the drugs acyclovir, famciclovir, valacyclovir indicated for?

Answer 18

• Herpes simplex types 1 and 2
• Herpes zoster
• Chicken pox

Question 19

What is amantadine hydrochloride indicated for?

Answer 19

Influenza A

Question 20

What are zanamivir and oseltamivir phosphate indicated for?

Answer 20

Influenza A and B

Question 21

What is the mechanism of action of most non-HIV antivirals?

Answer 21

Most of the current antiviral drugs work by blocking the activity of a polymerase enzyme that normally stimulates the synthesis of new viral genomes.

Question 22

What diseases are non-HIV anti-viral drug used to treat?

Answer 22

• Influenza viruses
• HSV, VZV
• CMV
• Hepatitis A, B, C