Pharm antivirals Flashcards

1
Q

are antiretrovirals virustatic or virucidal?

A

virustatic

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2
Q

what are the five major classes of antiretroviral medications?

A
  1. nucleoside reverse transcriptase inhibitors (NRTI’s) and nucleotide RTI’s (tenofovir))
  2. non-nucleoside reverse transcriptase inhibitors (NNRTI’s)
  3. protease inhibitors
  4. entry inhibitors
  5. integrase inhibitors
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3
Q

what are the NRTI’s?

A

zidovudine, lemivudine, emtricitabine, abacavir, tenofovir

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4
Q

what is the mechanism of NRTI’s?

A

viral DNA chain termination via inhibition of viral reverse transcriptase. Tenofovir is a nucleoTide, the others are nucleosides and need to be phosphorylated to be active

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5
Q

what does zidovudine mimic? lemivudine? emtricitabine? abacavir? tenofovir?

A
zidovudine = thymidine.
lemivudine = cytosine.
emtricitabine = cytosine.
abacavir = guanine.
tenofovir = adenosine.
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6
Q

which NRTIs can also be used for HBV?

A

lamivudine, emtricitabine, tenofovir

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7
Q

zidovudine side effects

A

granulocytopenia, anemia, nausea, vomiting

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8
Q

lamivudine and emtricitabine side effects

A

headache, nausea, vomiting, rash, neutropenia, pancreatitis (NOT SERIOUS)

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9
Q

abacavir side effects

A

hypersensitivity reaction - associated with HLA-B5701 mutation

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10
Q

tenofovir side effects

A

nephrotoxicity

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11
Q

what are the NNRTI’s?

A

efavirenz, nevirapine, rilpivirine, etravirine

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12
Q

NNRTI’s mechanism

A

inhibit reverse transcriptase through direct enzyme inhibition (do not require phosphorylation to be active) - NONCOMPETITIVE!

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13
Q

what are NNRTI’s and NRTI’s used to treat?

A

HIV

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14
Q

NNRTIs side effects

A

rash and hepatotoxicity - efavirenz also has vivid dreams and CNS symptoms (stop when ax wielding elves appear in dream!), teratogenic, P450 metabolism

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15
Q

what are the HIV protease inhibitors?

A

-navir (NA VIRUS! NO NEW VIRUS!)

ritonavir, fosamprenavir, atazanavir, darunavir, lopinavir

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16
Q

HIV protease inhibitors (-navir) mechanism

A

prevent cleavage of protein chain into functional subunits

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17
Q

which HIV protease inhibitor has “good” drug interactions? how?

A

ritonavir “boosts” other drug concentrations by inhibiting cytochrome P-450

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18
Q

HIV protease inhibitors (-navir) side effects

A

GI intolerance (n/v, diarrhea), metabolic toxicities!! (dyslipidemia, hyperglycemia, lipodystrophy)

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19
Q

what are the 3 steps of HIV attachment and fusion?

A
  1. HIV gp120 binds CD4 molecule
  2. conformational change occurs in gp120 and then binds the coreceptor CCR5 or CXCR4
  3. further conformational changes in gp120 expose gp41 protein which mediates fusion of the viral and cell membranes
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20
Q

what are the HIV entry inhibitors?

A

enfuvitide and maraviroc

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21
Q

enfuvirtide mechanism

A

binds gp41, inhibiting viral entry

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22
Q

enfuvirtide side effects

A

skin reaction at injection sites

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23
Q

maraviroc mechanism

A

binds CCR-5 on surface of Tcells/monocytes, inhibiting interaction with gp120 - TARGET IS ON HOST CELL!

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24
Q

maraviroc side effects

A

hepatotoxicity (rare) - cough, fever, URI, rash, musculoskeletal symptoms, ab pain, dizziness

25
Q

what are the integrase inhibitors?

A

-tegravir (GRAB the HIV before it integrates!)

raltegravir, elvitegravir, dolutegravir

26
Q

integrase inhibitors mechanism

A

inhibits HIV genome integration into host cell chromosome by reversibly inhibiting HIV integrase

27
Q

integrase inhibitors (-tegravir) side effects

A

myopathy and rhabdo - headache, neausea, diarrhea, pyrexia

28
Q

what are the common HAART regimen combinations?

A

3 active agents together; typically 2 NRTIs + integrase inhibitor, PI, or NNRTI

29
Q

what is commonly prescribed as initial therapy in HIV? disadvantage of this class?

A

NNRTI based regimen because of advantage of lower pill burden (preserve PI for later use). disadvantage is only one single mutation is needed to confer resistance and cross resistance develops for entire class

30
Q

what is the preferred NNRTI? exception?

A

efavirenz - exception pregnancy

31
Q

hepatitis C virus virology

A

ssRNA virus belonging to Flavivirdae - most common serotypes 1a and 1b

32
Q

what are the old drug classes used for treating HCV?

A

ribavirin (nucleoside analog - high risk of anemia) and interferon (indirect mechanism - side effects and poor efficacy)

33
Q

what are the newer drug therapies used for HCV?

A

nucleoside/nucleotide NS5B polymerase inhibitors, NS5A inhibitors, NS3/4A protease inhibitors

34
Q

what are the NS5B polymerase inhibitors?

A

sofosbuvir and partaprevir

35
Q

what are the NS5B polymerase inhibitors (sofosbuvir and partaprevir) mechanism?

A

compete with viral nucleotide to cause chain termination - active across all HCV genotypes

36
Q

NS5B polymerase inhibitors (sofosbuvir and partaprevir) side effects

A

relatively safe - fatigue, headache, GI, anemia

37
Q

what are the NS5A inhibitors?

A

ledipasvir, daciatasvir, ombitasvir

38
Q

NS5A inhibitors mechanism

A

inhibits HCB NS5A viral phophoprotein required for viral replication

39
Q

NS5A side effects

A

relatively safe - fatigue, headache, GI

40
Q

what are the NS3/4A protease inhibitors?

A

-previr (PROTEASE)

simeprevir, boceprevir, telaprevir

41
Q

NS3/4A protease inhibitors mechanism

A

prevent viral maturation through the inhibition of protein synthesis

42
Q

NS3/4A side effects

A

differ slightly depending upon the agent: anemia, rash, itching, GI, drug interactions

43
Q

approach to HVC therapy

A

combination therapy! esp. simeprevir and sofosbuvir

44
Q

herpes virus virology and life cycle

A

dsDNA virus - clinical disease appears a few days after initial establishment of infection - viral particles taken up by nerves and transported to nerve cell bodies in dorsal root ganglia of spinal cord where reactivation occurs

45
Q

what drugs are used to treat HSV?

A

guanosine nucleoside antivirals:

acyclovir, penciclovir, valacyclorvir, famciclovir

46
Q

guanosince nucleoside antivirals (for HSV) mechanism

A

valacyclovir prodrug fro acyclovir; famciclovir prodrug of penciclovir. after phosphorylation by cellular enzymes, interferes with viral DNA synthesis by competing with DNA analogues to cause viral DNA chain termination

47
Q

acyclovir, penciclovir, valacyclovir, famciclovir side effects

A

CNS changes and renal dysfunction when used at higher doses

48
Q

what is the DOC for CMV infection?

A

ganciclovir (purine analog guanine)

49
Q

ganciclovir mechanism

A

afterphosphorylation, causes viral DNA chain termination

50
Q

ganciclovir side effects

A

neutropenia, thrombocytopenia (a GANG of cycle running over all the herpes and neutrophils)

51
Q

foscarnet clinical use

A

CMV retinitis in immunocompromised when ganciclovir fails and acyclovir-resistant HSV

52
Q

foscarnet mechanism

A

directly inhibits herpesvirus DNA polymerase or HIV reverse transcriptase - does not require any kinase activation so it is active against the purine analog guanine resistant

53
Q

foscarnet side effects

A

nephrotoxicity (reversible but severe), electrolyte abnormalities leading to seizures (hypo/hyper calcemia, phosphatemia, hypomagnesmia, hypokalemia), myelosuppression

54
Q

best strategy for influenza

A

vaccination!

55
Q

what is used to treat influenza?

A
neuraminidase inhibitors (-mivir) = ME most likely to get flu;
oseltamivir, zanamivir, peramivir
56
Q

neuraminidase inhibitors (-mivir for flu) mechanism

A

prevent viral release from host cells by inhibiting influenza neuraminidase

57
Q

neuraminidase inhibitors side effects

A

GI, neuropsychiatric (agitation, anxiety, altered mental status)

58
Q

which of the neuraminidase inhibitors for influenza is inhaled therapy? IV formulation only? oral?

A

zanamivir inhaled; peramivir IV; oseltamivir oral

59
Q

who should receive therapy for influenza?

A

individuals with severe disease and those at high risk for ocomplications - can also be given as prophylaxis