Le33.Antivirals

Question 1

Acyclovir; When used? MOA?

Answer 1

Acyclovir is used to treat herpes and herpes like viruses. Acyclovir blocks nucleic acid synthesis

Question 2

Valacyclovir; When used? MOA?

Answer 2

Acyclovir is used to treat herpes and herpes like viruses. Acyclovir blocks nucleic acid synthesis

Question 3

What differentiates valacyclovir from acyclovir?

Answer 3

Valacyclovir is converted to acyclovir by enzymes in stomach during the first pass effect. Valacyclovir is replacing acyclovir

Question 4

Ganciclovir is a highly potent antiviral directed against what specific herpes like virus?

Answer 4

Ganciclovir is used only to target the Cytomegalovirus (CMV), which can lead to blindness in AIDS patients.

Question 5

What are the major side affects of ganciclovir?

Answer 5

Bone marrow supression including neutropenia, anemia, & thrombocytopenia

Question 6

Antiretroviral tx generally consists of a triple therapy. What types of drugs are generally employed in this therapy?

Answer 6

Two reverse transcriptase inhibitors plus one protease inhibitor

Question 7

What was the first AIDS drug that was tested with a placebo controlled study? WHat was the result of the study?

Answer 7

Zidovudine proved to be so effective that the study was stopped early so they could give the pts on the placebo zidovudine

Question 8

MOA of zidovudine?

Answer 8

Reverse transcriptase inhibitor. Works by inhibiting the synthesis of viral DNA from host RNA.

Question 9

Adverse side affect of zidovudine?

Answer 9

Bone marrow supression

Question 10

MOA of Didanosine & Lamivudine?

Answer 10

Reverse transcriptase inhibitors. When combined with zidovudine results in decreased resistance.

Question 11

Adverse side affects with didanosine & lamivudine? Why is Lamivudine preferred over didanosine?

Answer 11

Dose dependent Pacreatitis (can be deadly) & Hyperuricemia (don’t give to pts with gout). Lamivudine is replacing didanosine in popularity b/c it has less pancreatitis

Question 12

MOA of Efavirenz? When is Efavirenz’s use indicated?

Answer 12

Efavirenz is a newer reverse transcriptase inhibitor that is used as the 3rd drug in the triple drug regimen if protease inhibitors are contraindicated

Question 13

MOA of drugs ending in ‘-navir’? Such as Indinavir, Ritonavir & Saquinavir

Answer 13

Drugs ending in -navir are all protease inhibitors, which interfere with the final assembly of the HIV growth cycle by not allowing protease to cut proteins into usable sizes

Question 14

MOA of amantadine (symmetrel)?

Answer 14

Anti-influenza virus that blocks viral uncoating.

Question 15

MOA of Rimantadine (Flumadine)?

Answer 15

Blocks viral uncoating. Used to tx the flu.

Question 16

Why is Rimantadine Riplacing amantadine?

Answer 16

B/c amantadine induces the release of dopamine (Amantadine is also an anti-parkinsons drug) at higher rates than Rimantidine. So see less nervousness, difficulty concentrating, psychotic symptoms & tachycardia on rimantadine

Question 17

What is the MOA of Zanamivir (Relenza) and Oseltamivir (Tamiflu)?

Answer 17

The ‘-amivir’ drugs block packaging and assembly of the flu virus by inhibiting the neuraminidase enzyme. Neuraminidase is an enzyme on the surface of the flu virus that plays a role in the release of viruses, following duplication, from an infected cell.

Question 18

What is the difference b/t Zanamivir (Relenza) and Oseltamivir (Tamiflu)? What is an adverse rxn seen only in relenza?

Answer 18

Zanamivir (relenza) is only available in an inhaled form while Oseltamivir (tamiflu) is available orally. Zanamivir has resulted in severe bronchospasms in pts w/ upper airway disease (such as asthma)