EXAM 3 Antivirals Flashcards
___ are the proteins that are on the surfaces of viruses that are recognized by the host’s immune system
antigens
during reproduction, antigens on newly formed viruses may evolve signle or few mutations that reduce the host’s immune system’s ability to recognize the virus. this describes ___
antigenic drift
___ describes changes that are significant or frequent enough to cause viral resistance, which may lead to epidemics
antigenic shifts
viral genetic material may be either ___ or ___, but generally contains only enough material for virus to replicate itself using the host
DNA-encoded or RNA-encoded
what is an example of a DNA-encoded virus?
herpes virus
what 6 drugs are inhibitors of viral transcription via inhibition of DNA polymerase?
- acyclovir
- valacyclovir
- famcyclovir
- penicyclovir
- ganciclovir
- foscarnet
what is an example of an RNA-encoded virus?
influenza virus
___ is an inhibitor of virual uncoating (M2 protein)
amantadine
___ is an inhibitor of viral translation by inhibition of RNA polymerase
ribavarin
___ and ___ are neuroaminidase inhibitors (prevent viral release)
zanamivir and oseltamivir
what are the two types of herpes simplex virus?
- type 1 - HSV-1 or oral herpes
- type 2 - HSV-2 or genital herpes
___ typically resides in ___ and causes sores around the mouth, throat, inside of the cheeks, front of the tongue, gums, roof of mouth, and lips (also known as fever blisters or cold sores)
- HSV-1
- trigeminal ganglia
___ typically resides in ___ and tends to re-occur in the genital area, inner thighs, and buttocks
- HSV-2
- sacral ganglia (at the base of the spine)
___% of americans will develop shingles at some point in their life
32%
1 in 6 americans aged 14-49 years are infected with ___
HSV-2
VZV is a member of the ___ family and causes ___ and ___
- herpes (HHV3)
- chickenpox (primary infection)
- shingles (reactivation/recurrent)
- *VZV = varicella zoster virus
T or F:
VZV (HHV-3) transmission can be given to individuals who have already been infected
false
VZV transmission is only to those individuals with no history of VZV infection or vaccine exposure
describe chickenpox
- clinical presentation of VZV primary infection
- contagiousness - lasts from 1-2 days pre-rash until all lesions are gone (7-10 days total)
describe shingles
- clinical presentation of reactivated/recurrent VZV infection
- may occur years-decaes after initial chickenpox, but most frequent later in life or during immunocompromise
- postherpetic neuralgia
all members of the herpes virus family may establish ___ infections that become dormant, or ___, infections that may reactivate in response to various triggers
- primary
- latent
what are common triggers for reactivation of latent herpes viruses?
stress, fatigue, sun exposure, surgery, fever, menstrual periods, or being immunocompromised
the age-related decline in immune function, known as ___, increases the incidence of herpes reactivation (shingles) in elderly patients
immunosenescence
what is the location, appearance, and contagiousness of canker sores?
- location: inside the mouth and on the gums
- appearance: white, yellow, or gray center and bright red border; can be single or in groups
- contagious? no
describe the cause, location, appearance, and contagiousness of cold sores
- cause: HSV
- location: mostly outside of the mouth
- appearance: red blisters, typically in groups
- contagious? yes
which antiviral drug is primarily prescribed for HSV, is less active against VZV, and can be administered oral, IV, or topical?
acyclovir
which antiviral drug is converted to acyclovir and should be administered orally only
valacyclovir
which antiviral drug is used for orofacial or genital HSV-related sores and should be administered topically only due to poor oral absorption?
penicyclovir
which antiviral drug is metabolized to pencyclovir, is mainly used for VZV infections (shingles), and should be administered orally only (overcomes poor absorption of peniciclovir)?
famcyclovir
what is the efficacy for VZV of valacyclovir, acyclovir, and famcyclovir?
famciclovir >/= valacyclovir >>> acyclovir
patients must always hydrate well while on any ___ drug to avoid ___
- -cyclovir
- crystalline nephropathy
which 2 antivirals are used to treat HSV and/or cytomegalovirus (CMV) infections?
gancyclovir and foscarnet
the following adverse effects are indicative of what antiviral?
due to its high risk of cytotoxicity, it must be administered in a clinical setting and monitored closely
gancyclovir
what are the contraindications of gancyclovir?
- during pregnancy - teratogenic and mutagenic
- in males who wish to have children - inhibits spermatogenesis
___ is much safer than gancyclovir and is useful in acyclovir- or gancyclovir- resistant HSV or CMV infections
foscarnet
what is the method of action of foscarnet?
selectively inhibits viral DNA polymerase enzymes (not kinases)
unlike acyclovir and gancyclovir, ___ is not activated by viral kinases. that is why it is useful in acyclovir- and gancyclovir- resistant HSV and CMV infections
foscarnet
foscarnet should be administered via ___ only
IV
what is the main adverse effect of foscarnet?
reversible nephrotoxicity
___ is available by prescription for prophylaxis or treatment of influenza A and B viruses
oseltamivir (tamiflu)
oseltamivir (tamiflu) is a ___ inhibitor
neuroaminidase
why is early administration of oseltamivir crucial?
- when a 5 day course of treatment is initiated within 48 hours from onset of flu symptoms, the duration of flu symptoms are decreased by up to 1-2 days
what is the main adverse effect of oseltamivir (tamiflu)?
disulfuram-like reactions
what is the clinical use of zanamivir (relenza)?
for the treatment and prophylaxis of influenza A and B
what is the mechanism of zanamivir (relenza)?
neuroaminidase inhibitor
___ is available as an inhaler only
zanamivir (relenza)
what are the side-effects of zanamivir (relenza)?
disulfuram-like reactions
___ is contraindicated in patients with severe asthma, COPD, or allergies to milk proteins. deep inhalation of the drug can induce bronchospasm and has been associated with rare deaths in patients with poorly controlled asthma and/or COPD
zanamivir (relenza)
___ is only active against influenza A (not active against B)
amantadine
amantadine is a ___ drug historically used as an antiviral for influenza A
anti-parkinson’s disease
what are the two basic mechanisms of amantadine?
antiviral and anti-PD
amantadine is no longer used as an antiviral due to ___
nearly 100% resistance of influenza A
the following adverse effects are common to what antiviral?
ataxia, dizziness, anxiety, slurred speech
amantadine
the following are contraindications of what antiviral?
patients with renal impairment, epilepsy, closed angle glaucoma, or during pregnancy
amantadine
