Antivirals Flashcards

1
Q

Which viral infections require antivirals and why?

A

covid - rep failure
chickenpox - varicella pneumonitis
herpes - encephalitis
viral hep - chronic hep C
Mpox - eye lesions

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2
Q

Which viruses do you always treat?

A

HIV

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3
Q

Aims of antiviral treatment

A

reduce mortality
reduce morbidity (severity/duration)
prevent the occurrence in those at risk
reduce transmission from people infected

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4
Q

Which viral processes can antivirals interfere with?

A

reverse transcription (retroviruses)
transcription
translation
release (cell lysis)

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5
Q

Herpesviruses - what type of virus are they?

A

DNA viruses

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6
Q

What is the difference in disease course of RNA and DNA viruses?

A

RNA - acute infection
(except retroviruses)

DNA viruses - acute asymptomatic acute infection and then chronic infection and you never clear them

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7
Q

Key difference between meningitis and encephalitis

A

encephalitis is inflammation of the brain parenchyma (the brain tissue itself)
-> fever, reduced GCS, seizures, CN abnormalities,
-> usually viral or autoimmune
-> very deadly, 1/2 people with untreated HSV encephalitis will die

Meningitis -> inflammation in the lining of the neck
-> stiff neck, photophobia,
-> usually bacterial

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8
Q

Key difference between meningitis and encephalitis

A

encephalitis is inflammation of the brain parenchyma (the brain tissue itself)
-> fever, reduced GCS, seizures, CN abnormalities,
-> usually viral or autoimmune
-> very deadly, 1/2 people with untreated HSV encephalitis will die

Meningitis -> inflammation in the lining of the neck
-> stiff neck, photophobia,
-> usually bacterial

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9
Q

Mx of viral encephalitis

A

IV aciclovir 10 mg/kg TDS

start on suspicion, then get MRI and LP

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10
Q

What encephalitis causes does aciclovir work for?

A

HSV
varicella

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11
Q

What drug type is aciclovir?

A

guanosine analogue
4-5x/d

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12
Q

what drug type is valaciclovir?

A

pro drug - guanosine analogue

oral only
more expensive
TDS

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13
Q

Differences between aciclovir and valaciclovir

A

valaciclovir pro drug - guanosine analogue

A: oral and IV, 4-5x/d
V: oral only, TDS

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14
Q

What activates aciclovir/valaciclovir

A

viral thymidine kinase

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15
Q

CMV - when do we worry about it?

A

immunosuppressed patients

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16
Q

what can CMV cause

A

colitis
pneumonitis
hepatitis
retinitis
BM suppression

encephalitis/ventriculitis
nephritis
cystitis
myocarditis

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17
Q

When do we treat CMV infection?

A

only if there is CMV disease

if someone is immunosuppressed and has CMV infection you may monitor the viral load regularly and treat if it Strats going up

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18
Q

When do we treat CMV infection?

A

only if there is CMV disease

if someone is immunosuppressed and has CMV infection you may monitor the viral load regularly and treat if it Strats going up

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19
Q

CMV drugs

A

1st line: guanosine analogue
ganciclovir (IV - SE: BM suppression, CI in BM transplant recipients)
valganciclovir (PO)

2nd foscarnet (IV/intravitreal SE: nephrotoxic)

20
Q

BMT patients with CMV disease - what drug?

A
21
Q

2nd line drugs after aciclovir/valaciclovir

A
22
Q

EBV management - when antivirals?

A

if patient had transplant
in renal transplant patients

PTLD ->

23
Q

PTLD

A

post transplant lymphoproliferative disease (polyclonal infection)

seen post EBV infection in immunocompromised

oncogenic - you get B sx and this can also progress to lymphoma

can also give rituximab

24
Q

Influenza - what antivirals can you use?

A

oseltamivir (tamiflu) - PO or NG
zanamivir (can be inhaled or given IV)

25
Q

What type of drug is oseltamivir?

A

neuraminidase inhibitor

26
Q

Commonest cause of children under 2 being admitted to hospital?

A

RSV infection -> bronchiolitis

27
Q

what drug could you use for RSV bronchiolitis?

A

Ribavirin (not strong evidence for it)
IVIG

28
Q

What meds can you give to prevent RSV disease?

A

Palivizumab
Nirsevimab - not yet licensed, but longer duration of effect

29
Q

Palivizumab

A

monoclonal Ab that sticks to fusion protein of RSV

30
Q

Treatments for covid

A

early infection (to prevent severe disease)
- nirmatrelvir/ritonavir (Paxlovid) - many drug interactions
- remdesivir (IV)
- molnupiravir (PO but less effective than above)
- sotrovimab

Infection (late) - focus on host and not the virus
- steroids
- baricitinib ()
- IL-6 inhibitor ()

31
Q

Oseltamivir - MoA

A

directly inhibits neuraminidase of influenza virus (it is what lets the virus get out of an infected cell)

32
Q

M-pox antiviral

A

Tecoviromat

33
Q

Who is at high risk of tecoviromat?

A

immunocompormised/pregnant/paediatric

34
Q

indications to treat m-pox

A

> 100 lesions
sepsis
encephalitis
sensitive areas of infection
immunocompromised?

35
Q

what vaccine can you give to prevent mpox?

A

smallpox?

36
Q

what vaccine can you give to prevent mpox?

A

smallpox?

37
Q

BK virus - what drugs can you give>

A

cidofivir (+probe

38
Q

BK virus - what is it?

A
39
Q

Adenovirus - who needs Mx?

A

transplant patients, especially paediatric

can give IVIG

can try cifofovir/xxxfovir

40
Q

Cellular immunotherapy

A

adoptive immunotherapy
virus specific cytotoxic T cells
donor lymph
???

41
Q

Drug resistance with antivirals - causes and issues

A

diversity, selection pressure

treatment failure

2nd line drugs are usually less effective and more toxic

42
Q

Drug resistance with antivirals - causes and issues

A

diversity, selection pressure

treatment failure

2nd line drugs are usually less effective and more toxic

43
Q

Drug resistance testing

A
  1. phenotypic testing (cell culture, different concentrations of antivirals, check for replication) - mainly HSV
  2. genotypic (sequencing/resistance mutations) - mainly HIV and some Hep
44
Q

Main mechanism of resistance against aciclovir in HSV

A

thymidine kinase mutations (95%) -> drug cannot activate itself and work

(DNA polymerase mutations are a second much rarer cause - 5%)

45
Q

Drug resistance in flu

A

H257y - neuraminidase mutation that gives resistance to XXX but not XXX

46
Q

PEP

A

Hep B
Rabies
Variclella zoster