Antiviral medications

Question 1

what is the adult and child dose for oseltamivir?

what is the dose for prophylaxis?

Answer 1

adult dose 75mg BID for 5 days
child dose 30-75mg BID for 5 days
prophylaxis 75mg OD for 10 days

Question 2

oseltamivir and zanamivir belong to which class

Answer 2

neuraminidase inhibitors

Question 3

what is the MOA of oseltamivir and zanamivir

Answer 3

Oseltamivir and Zanamivir inhibit neuraminidase and virions accumulate at the internal infected cell surface without release

Question 4

neuraminidase inhibitors are effective against ifluenza A, B and C. t/f

Answer 4

false. only infleunza A and B

Question 5

oseltamivir and zanamivir are taken orally. t/f

Answer 5

false. oseltamivir is taken orally, zanamivir is inhaled or taken intranasally

Question 6

zanamivir should be avoided in patients with _________.

Answer 6

COPD and asthma

Question 7

what is the adverse effect associated with oseltamivir

Answer 7

GIT discomfort

Question 8

name the drugs which act by inhibiting viral uncoating

Answer 8

amantadine and rimantadine

Question 9

what is the MOA of amantadine/rimantadine

Answer 9

These drugs block the viral membrane matrix protein M2 which is required for fusion of the viral membrane with the cell membrane to form the endosome.
They also interfere with the release of new virions.

Question 10

amantadine/rimantadine are effective only against ________.

Answer 10

infleunza A virus

Question 11

amantadine/rimantadine arnot effective against vaccines why?

Answer 11

used to supplement vaccinations

Question 12

which drug crosses the BBB

a. amantadine
b. rimantadine

Answer 12

a. amantadine

Question 13

amantadine is teratogenic but rimantadine is not. t/f

Answer 13

false. both are teratogenic

Question 14

amantadine causes CNS problems whereas rimantadine does not. t/f

Answer 14

true because rimantadine does not cross the BBB

Question 15

both amantadine/rimantadine cause GI problems. t/f

Answer 15

true

Question 16

what are the therapeutic indiations of ribavirin

Answer 16

Effective against many RNA and DNA viruses
Used in severe respiratory syncytial virus bronchiolitis in infants and children
Used in combination with interferon for chronic hepatitis C

Question 17

MOA of ribavirin

Answer 17

Ribavirin prevents mRNA capping and blocking of RNA polymerase

Question 18

is ribavirin effective against all viruses?

Answer 18

no, ribavirin is only effective against viruses that synthesize mRNA

Question 19

adverse effects of ribavirin

Answer 19

Dose dependent anemia in oral and parenteral use.
Elevated Bilirubin
Teratogenicity

Question 20

ribavirin has good CNS penetration. t/f

Answer 20

false. it has poor CNS penetration.

Question 21

what are the 2 drug combinations for hepatitis A and B

Answer 21

Hepatitis B – Interferon or Lamivudine

Hepatitis C – Interferon + Ribavirin

Question 22

what is an interferon. where is it used.

Answer 22

This is a naturally occurring glycoprotein that is synthesized by recombinant DNA technology
Utilized in management of Hepatitis B and C

Question 23

MOA of interferon

Answer 23

IFN bind to ganglioside receptors on host cell membranes. They induce the production of enzymes that inhibit the translation of viral mRNA into viral proteins so halting viral replication.

Question 24

what is the IFN half life

Answer 24

2-4 hrs

Question 25

IFN is administered orally only. t/f

Answer 25

false. Administered Scut or IV but not orally.

Question 26

what are the drug interactions of IFN

Answer 26

Potentiate bone marrow depression of other drugs such as Zidovudine

Question 27

MOA of lamivudine

Answer 27

Cytosine analog (phosphorylated by host cell enzymes to the active form) that inhibits HBV DNA polymerase and HIV reverse transcriptase

Question 28

uses of lamivudine

Answer 28

Used for Hepatitis B infections | Used for HIV infections in combination with other drugs.

Question 29

lamivudine requires dose adjustment in renal failure. t/f

Answer 29

true

Question 30

uses of acyclovir

Answer 30

``` HSV-1 HSV-2 Varicella-zoster virus (VZV) Epstein-Barr Virus DOC in HSV encephalitis Commonly used for genital herpes infections ```

Question 31

MOA of acyclovir

Answer 31

Acyclovir is a guanosine analog that is phosphorylated by viral thymidine kinase enzyme It is further di and tri phosphorylated by the host cells and competes with dGTP for viral DNA polymerase. It becomes incorporated into the viral DNA causing premature DNA chain termination. Irreversible binding of acyclovir to viral DNA polymerase inactivates the enzyme

Question 32

acyclovir does not cross the BBB. t/f

Answer 32

false. it crosses the BBB

Question 33

Valacyclovir side effects

Answer 33

Gi disturbances, thromcytopenic purpura

Question 34

Foscarnet MOA

Answer 34

Reversibly inhibits viral DNA and RNA polymerases thereby inhibiting chain elongation.

Question 35

foscarnet uses

Answer 35

Used for CMV retinitis and acyclovir-resistant HSV and Herpes zoster infections

Question 36

ganicyclovir MOA

Answer 36

Acyclovir analog that inhibits DNA polymerase and is incorporated into DNA to decrease chain elongation

Question 37

ganicyclovir uses

Answer 37

Used for CMV retinitis and CMV prophylaxis in transplant patients

Question 38

MOA NRTIs

Answer 38

They are analogs of nucleosides or nucleotides lacking the 3’-OH group Once they enter cells they are converted to triphosphate form by enzymes Competes with equivalent host cell triphosphate substrates for DNA synthesis by viral reverse transcriptase.

Question 39

name a drug used in prophylaxis of HIV for pregnant and lactating females and infants.

Answer 39

zidovudine, azidothymidine

Question 40

AZT Adverse effects

Answer 40

GIT disturbances Bone marrow depression – Blood disorders (anemia and neutropenia) CNS – Insomnia, Dizziness, Headaches

Question 41

moa lamivudine

Answer 41

It terminates synthesis of viral DNA by inhibition of reverse transcriptase of both HIV and HBV

Question 42

name a drug for HIV ttt that does not affect mitochondrial DNA synthesis or bone marrow cells

Answer 42

lamivudine

Question 43

MOA NNRTIs

Answer 43

Highly selective noncompetitive inhibitors of HIV-1 reverse transcriptase enzyme They bind to reverse transcriptase enzyme leading to conformational changes and enzyme inhibition. Do not require activation by cellular enzymes

Question 44

treatment with ________ leads to _________ in CD$+ cells and ________ in viral load

Answer 44

efavirenz, increase, decrease

Question 45

absorption of efavirenz decreases with fatty meals. t/f

Answer 45

false. increases

Question 46

half life of efavirenz

Answer 46

t1/2 = 40 hours (once daily dosing)

Question 47

efavirenz is teratogenic. t/f

Answer 47

true

Question 48

MOA of indinavir/ nelfinavir

Answer 48

They inhibit HIV aspartyl protease enzyme. This enzyme is responsible for cleavage of the viral polyprotein into essential enzymes and structural proteins This prevents maturation of viral particles Protease does not occur in host – useful target for selective intervention

Question 49

indinavir/ nelfinavir are ___________ inhibitors.

Answer 49

HIV Protease Inhibitors

Question 50

Buffalo Hump due to accumulation of fat at the base of the neck is due to...?

Answer 50

indinavir/ nelfinavir