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Pharm Exam 4 > Antifungal Antiviral > Flashcards

Flashcards in Antifungal Antiviral Deck (78)
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1
Q

What are 3 reasons fungal infections are difficult to treat?

A
  1. They are similar to animal cells
  2. Slow growth rate
  3. Occur in poorly vascularized tissue
2
Q

What are three fungal infection classes?

A
  1. Systemic
  2. Superficial/mucocutaneous
  3. Dermatomycoses
3
Q

What is the term for fungal infections of systemic organs (aspergillus, blastomyces, Cryptococcus, histoplasma, coccidioises)?

A

Systemic mycoses

4
Q

What is the term for fungal infections involving the outer layers of skin, nails, or mucous membranes

A

Superficial/mucocutaneous mycoces

5
Q

What is one of the most common mucocutaneous mycoses?

A

Candidiasis of mouth (thrush), GI, vagina

6
Q

What is the term for slightly deeper fungal infections of the skin, hair, or nails by dermatophytes?

A

Dermatomycoces

7
Q

Name 3 classes of drugs for treating systemic fungal infections

A
  1. Membrane pore formers
  2. Ergosterol synthesis inhibitors
  3. DNA/RNA synthesis inhibitors
8
Q

What is the prototype for Membrane Pore Formers for fungal infection treatment?

A

Amphotericin B

9
Q

Amphotericin B is a member of what drug class?

A

Polyene macrolide (polyene = series of conjugated double bonds)

10
Q

What is amphotericin B’s mechanism of action?

A

selective binding to ergosterol in fungal membrane

11
Q

What is chemical quality of Amphotericin B that allows it to form membrane pores by binding to ergosterols?

A

Amphoteric = likes both lipid and water

12
Q

What is the administration for amphotericin B?

A

Parenterally (other than alimentary route). Intrathecal admin (under arachnoid membrane of brain or spinal cord[internet]) for fungal meningitis

13
Q

For what is amphotericin B is the DOC?

A

Systemic fungal infections (blastomycoces, cryptococcal, histoplasmosis)

14
Q

What is the main side effect of amphotericin B

A

Nephrotoxicity, especially in pt with renal problems or taking other nephrotoxic drugs (aminoglycosides)

15
Q

What is an azole drug?

A

An ergosterol synthesis inhibitor for systemic fungal infection

16
Q

Can azole drugs affect cholesterol in animal cells?

A

Yes, but they are selective for fungal ergosterol

17
Q

What was the first orally available broad spectrum antifungal drug?

A

Ketoconazole

18
Q

Name 3 systemic azole drugs (ergosterol synthesis inhibitors).

A

Ketoconazole
Fluconazole
Itraconazole

19
Q

What are 3 topical azole drugs (ergosterol synthesis inhibitors) one of which can also be used systemically?

A

Miconazole
Clotrimazole
Ketoconazole

20
Q

What are 3 disadvantages of ketoconazole?

A

Inhibit CYP3A4 causing drug interactions
Hepatotoxicity
Gynecomastia

21
Q

What is the DOC for fungal meningitis?

A

Fluconazole (cryptococcal meningitis)

22
Q

What are other uses of fluconazole?

A

Candidemia (blood borne candidiasis) Vaginal candidiasis
Oropharyngeal and esophageal candidiasis
Prophylaxis of fungal disease in immunocompromised and transplant patients

23
Q

Name a DNA/RNA synthesis inhibitor

A

Flucytosine

24
Q

Of what is flucytosine an analogue?

A

Cytosine (a nucleotide)

25
Q

What must happen to Flucytosine for it to be active

A

Must be metabolized in fungal cell to active form

26
Q

What is the active form of flucytosine?

A

5-fluorouracil

27
Q

What is the mechanism of flucytosine?

A

Active form 5-fluorouracil inhibits thymidylate synthesis, required for synthesis of DNA and RNA

28
Q

Is flucytosine narrow spectrum or broad spectrum?

A

Narrow because fungus must be able to metabolize flucytosine to activate it to 5-fluorouracil

29
Q

What infection can flucytosine be used for (second line)?

A

Cryptococcal meningitis

30
Q

When is flucytosine most useful and why?

A

When used in combo therapy because fungi develop quick resistance

31
Q

What is a side effect of flucytosine?

A

Bone marrow depression

32
Q

Nystatin is used for what fungal infections?

A

Topical infections

33
Q

What drug class does nystatin belong to?

A

Polyene class (pore formers[amphoteric] same as Amphotericin B)

34
Q

Can Nystatin be used orally?

A

Yes, but not for systemic due to toxicity. Used orally to treat oral candidiasis

35
Q

What are 2 oral formulations of Nystatin for treatment of oral candidiasis?

A
  1. ) Aqueous suspension: 5mL 4 times/day 2 min/swish. Has sucrose so diabetic consideration
  2. ) Nystatin pastilles:dissolve in mouth 15 min/4 times day. Better b/c in there longer
36
Q

For how long are topical antifungals used?

A

10-14 days or for at least 48 hrs after infection symptoms subside

37
Q

What are 2 reasons viral infections are hard to treat?

A

Viruses are small, therefore have fewer drug targets
Viruses utilize host functions so hard to selectively
kill

38
Q

What type of drugs are used to treat Herpes virus infections?

A

Nucleoside analogues

39
Q

What is required for a nucleoside analogue drug to be used by a virus?

A

Must first be phosphorylated to the nucleotide form

40
Q

Why do nucleoside analogues target viruses better than human DNA?

A

Viral DNA polymerases are less discriminating so they use the nucleoside analogue quicker

41
Q

Once the nucleoside analogue has been incorporated into viral DNA, what do they lack and what does this cause?

A

Lack 3’ hydroxyl group required for next nucleotide to be added to chain causing chain termination

42
Q

Viral nucleoside analogues are also called what?

A

Chain terminators

43
Q

Which Herpes virus produces cold sores and eye infections?

A

HSV I (herpes labialis, herpes Keratitis)

44
Q

HSV II causes what diseases?

A

Genital herpes (latent periods w/ sporadic outbreaks)
Shingles (Herpes Zoster)
Cytomeglovirus (CMV retinitis)

45
Q

What takes genital herpes (HSVII) out of latency into active infection?

A

Stress or UV light

46
Q

Which HSVII infections are problems in immunocompromised?

A
Herpes Zoster (shingles)
CMV retinitis
47
Q

What is an orally available nucleoside analogue for the relief of symptoms from active herpes infection or prophylaxis of herpes in immunocompromised?

A

Acyclovir

48
Q

What is the mechanism of action for acyclovir?

A

It is taken up by herpes virus infected cell, converted to acyclovir monophosphate by viral thymadine kinase

49
Q

Why does acyclovir only work in herpes virus infected cells?

A

Only infected cells have the thymadine kinase, unifected don’t have it so can’t convert the acyclovir to active

50
Q

What is the active form of acyclovir and what is required to convert it to that?

A

Acyclovir monophosphate

Viral thymadine kinase

51
Q

Can herpes virus become resistant to acyclovir, and if so, how?

A

Yes, by decreased thymadine kinase activity

52
Q

What are common side effects for acyclovir?

A

Headache and insomnia

53
Q

What is the prodrug form of acyclovir designed to give higher bioavailability?

A

Valacyclovir (Valtrex)

54
Q

Is acyclovir curative or only symptom relief?

A

Symptom relief only

55
Q

Gancyclovir (cytovene) is structurally similar to acyclovir but requires what type of administration?

A

Parenteral (other than alimentary canal)

56
Q

What is the main use for Gancyclovir?

A

Treatment of serious infections (retinitis or pneumonia) caused by Cytomeglovirus (CMV)

57
Q

What is a major negative side effect for Gancylclovir?

A

Bone marrow depression

58
Q

What is an alternative drug for treating CMV and especially thymadine kinase deficient herpes (resistant herpes)?

A

Foscarnet (Foscavir)

59
Q

What is Foscarnet(Foscavir) a derivative of and how must it be administered?

A

Phosphonic acid derivative, administrated intravenously

60
Q

What are antivirals from pooled IgG immunoglobulins (antibodies) extracted from plasma of over one thousand blood donors

A

Immunoglobulins

61
Q

How are immunoglobulins administered and what is their duration of action?

A

Administered intravenously or parenteral injection

Effective for 2 weeks to 3 months

62
Q

)Immunoglobulins used for treatment of what?

A

Immunodeficient patient low antibiody levels

63
Q

Natural proteins produced in the body for antiviral and immunomodulation are what?

A

Interferon

64
Q

What are 3 natural classes of interferon?

A
  1. Interferon Alpha
  2. Interferon Beta
  3. Interferon Gamma
65
Q

What is the most common use for Interferons?

A

treat Hepatitis B, Hepatitis C
Leukemia
Multiple Sclerosis (autoimmune affecting brain and spinal cord [internet])

66
Q

What is the common side effects from interferon treatment?

A

flu-like (myalgia, fatigue, headache, chills, nausea, vomiting, diarrhea)

67
Q

What are 2 new anti-Influenza drugs?

A

Amantadine (Symmetrel)

Rimantadine (Flumadine)

68
Q

Amantadine and Rimantadine are only effective against what influenza?

A

Influenza A

69
Q

What is the administration of amantadine and rimantadine and when is it taken?

A

Oral administration after initial symptoms of flu

70
Q

Can Amantadine and Rimantadine be used prophylactically to prevent flu virus infection?

A

Yes

71
Q

What are the goals of Amantadine and Rimantadine treatment or prophylaxis?

A

Reduce severity of influenza A virus Decrease risk of serious influenza virus Minimize flu spread in institutions

72
Q

How are Amantadine and Rimantadine believed to act on Influenza A?

A

Via M2 channel binding, it blocks the uncoating of the flu virus after it has penetrated the host cell

73
Q

What is another disease, not viral, that Amantadine and Rimantadine are used to treat?

A

Parkinson’s

74
Q

Name 2 Neuraminidase inhibitors

A

Zanamivir (Relenza) Oseltmavir (Tamiflue)

75
Q

What is neuraminidase

A

Enzyme spike on influenza A and influenza B viral coat

76
Q

What does neuraminidase do to the host cell surface?

A

Cleaves sialic acid residue on cell surface necessary for final release of viral progeny from infected cell

77
Q

How do Zanamivir (Relenza) and Oseltmavir (Tamiflu) work?

A

They are sialic acid analogues that bind and inhibit neuraminidase

78
Q

What are 2 uses of Zanamivir (Relenza) and Oseltmavir(Tamiflu)?

A

reduce flu symptoms if taken within 30 hours of symptoms

prophylaxis