Post on 09-Apr-2018
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ANTIVIRAL
AGENTS
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Viruses cause variety ofconditions
Warts , common cold, flu
Chicken pox, measles
Composed of DNA & RNA inside
protein coat.
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Replication cycle of a virus
a) Attachment
b) Penetration
c) replication
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Replication cycle of a virus
d) synthesis
e) assembly
f) release
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Viruses are contained inside human
cells difficult to develop effective drugs
that destroy a virus w/o harming
human host Interferons- released in response to
viral invasion, prevent replication
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Influenza A and respiratory
viruses
Include influenza B, respiratory
syncytial virus (RSV), invade respi
tract and cause symptom of flu
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Rimantadine prototype
Prophylaxis and txt of illness cause by
influenza A virus in adults Prophylaxis in children
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Drug-drug interactions
w/ antcholinergic drugs increase atropine
like effects
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Herpes & CMV
Herpes cold sores, encephalitis,
shingles, genital infections
CMV slightly different Affect eyes, respi tract, liver
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Therapeutic actions
Inhibit viral DNA replications by
competing with viral substrates to form
shorter, non effective DNA chains. Prevent replication of virus
Little effect on the host cells of human
cause their DNA uses different substrates
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Effective in immunocompromisedindividual (AIDS, multiple infection)
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Acyclovir
prototype
Herpes simplex virus 1 & 2 infections,
severe genital HSV infections,encephalitis, acute treatment
shingles,chicken pox
Ointment for genital herpes
Cream cold sores (herpes labialis)
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Drug-drug interactions
Risk nephrotoxicity when in combination
w/ nephrotoxic drugs
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Agents for hiv & aids
HIV attacks helper T cells w/in immune
system
Multiply w/in the cell When cell rupture, many new viruses are
released to attack other helper T cells
Loss of Immune reaction
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Lost T cell function AIDS or AIDSrelated complex (ARC)
Characterized by opportunistic
infections and Ca HIV mutates over time
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2 reasons difficult
treatment of AIDS/ ARC:1. Length of time the virus can remain
dormant w/in T cell
2. Adverse effects of drugs (depressimmune system)
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Agents treat HIV infection
Reverse trancriptase inhibitors
Protease inhibitors
Nucleosides
Fusion inhibitors
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Reverse transcriptase inhibitors
Binds directly to HIV reverse
transcriptase, blocking both RNA & DNA
dependent DNA polymerase activities Prevent transfer of information that
would allow the virus to replicate and
survive
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Blocks protease activity w/in HIV
virus Protease essential for maturation
of an infectious virus, w/o it, HIV
particle is immature andnoninfective.
Protease inhibitors
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prototype
Indinavir (Crixivan)
Txt of adults & children older 12 y.o w/
HIV Rapidly absorbed GIT, metabolize liver,
excreted urine
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nucleosides
Interfere w/ HIV replication by
inhibiting cell protein synthesis
leading viral death
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prototype
Zidovudine
Mgt of adults w/ symptomatic HIV
infections in combination w/ otherantiretrovirals
Prevention of maternal-fetal HIV
transmission.
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Fusion inhibitors
New class
Introduced 2003
Prevents fusion of virus w/ the humancellular membrane, w/c PreventsHIV-1
virus fro entering the cell.
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Therapeutic actions
treat HIV & AIDS operate @ various
points in life cycle of virus
result in its death & inactivation Use in combination
Txt AIDs or ARC who have decreased no T
cells & evidenced of increased
opportunistic infections
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Enfuvirtide (Fuzeon)
In combination w/ antiretroviral agents
to treat adults and children older 6 y.o.,
w/ evidenced ofHIV-1 replication despiteongoing therapy.
SQ; peak 4-8 hours
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Half-life : 3.2 4.4 hours
Asso. w/ insomnia, depression,
peripheral neuropathy, nausea, diarrhea,pneumonia, injection site reactions
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Locally active
antiviral agents Table 10.4
Prototype : Idoxuridine (Herplex)
applied directly to eye & is used to treatherplex simplex keratitis
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actions
Interfere with normal viral replication
and metabolic processes.
Indicated for specific local viral infections