elo173 slide antiviral agents
Antiviral Agents
!"
# #
# !
VIRUSES
• Obligate intracellular parasites
• Consist of a core genome in a protein shell and some
are surrounded by a lipoprotein
• lack a cell wall and cell membrane
• do not carry out metabolic processes
• Replication depends on the host cell machinery
VIRUSES
• Steps for Viral Replication
1) adsorption and penetration into cell
2) uncoating of viral nucleic acid
3) synthesis of regulatory proteins
4) synthesis of RNA or DNA
5) synthesis of structural proteins
6) assembly of viral particles
7) release from host cell
$
ANTIVIRAL AGENTS
• Block viral entry into the cell or must work inside the
cell
• Most agents are pyrimidine or purine nucleoside
analogs
%
SITES OF
DRUG
ACTION
&
Sites of Drug
Action
'
AntiHerpes Agents
•
•
•
•
•
•
Acyclovir - prototype
Valacyclovir
Famciclovir
Penciclovir
Trifluridine
Vidarabine
(
AntiHerpes Agents
Mechanism of Action
Acyclovir
• An acyclic guanosine derivative
• Phosphorylated by viral thymidine kinase
• Di-and tri-phosphorylated by host cellular enzymes
• Inhibits viral DNA synthesis by:
1) competing with dgtp for viral DNA polymerase
2) chain termination
AntiHerpes Agents
Mechanism of Resistance
Acyclovir
• Alteration in viral thymidine kinase
• Alteration in viral DNA polymerase
• Cross-resistance with valacyclovir, famciclovir, and
ganciclovir
AntiHerpes Agents
Clinical Uses
Acyclovir
• Oral, IV, and Topical formulations
• Cleared by glomerular filtration and tubular secretion
• Uses:
– Herpes Simplex Virus 1 and 2 (HSV)
– Varicella-zoster virus (VZV)
• Side Effects: nausea, diarrhea, headache, tremors, and
delirium
$
AntiHerpes Agents
Valacyclovir
• L-valyl ester of acyclovir
• Converted to acyclovir when ingested
• M.O.A.: same as acyclovir
• Uses:
– 1) recurrent genital herpes
– 2) herpes zoster infections
• Side Effects: nausea, diarrhea, and headache
%
AntiHerpes Agents
Famciclovir
• Prodrug of Penciclovir (a guanosine analog)
• M.O.A.: same as acyclovir
• does not cause chain termination
• Uses: HSV-1, HSV-2, VZV, EBV, and hepatitis B
• Side Effects: nausea, diarrhea, and headache
&
AntiHerpes Agents
Trifluridine
• Trifluridine- fluorinated pyrimidine
– Inhibits viral DNA synthesis same as acyclovir
– Incorporates into viral and cellular DNA
– Uses: HSV-1 and HSV-2 (topically)
AntiHerpes Agents
Vidarabine
• An adenosine analog
• inhibits viral DNA polymerase
• incorporated into viral and cellular DNA
• metabolized to hypoxanthine arabinoside
• Side Effects: GI intolerance and myelosuppression
'
Anti-Cytomegalovirus Agents
•
•
•
•
•
Gancyclovir
Valgancyclovir
Cidofovir
Foscarnet
Fomivirsen
(
Anti-Cytomegalovirus Agents
Ganciclovir
• An acyclic guanosine analog
• requires triphosphorylation for activation
• monophosphorylation is catalyzed by a
phosphotransferase in CMV and by thymidine kinase in
HSV cells
• M.O.A.: same as acyclovir
• Uses: CMV*, HSV, VZV,and EBV
• Side Effect: myelosuppression
Anti-Cytomegalovirus Agents
Valgancyclovir
• Monovalyl ester prodrug of gancyclovir
• Metabolized by intestinal and hepatic esterases when
administered orally
• M.O.A.: same as Gancyclovir
• Uses: CMV*
• Side Effect: myelosuppression
Anti-Cytomegalovirus Agents
Cidofovir
• A cytosine analog
• phosphorylation not dependent on viral enzymes
• Uses: CMV*, HSV-1, HSV-2, VZV, EBV, HHV-6,
adenovirus, and human papillomavirus
• Side Effects: nephrotoxicity (prevented by admin. of
probenecid)
• Resistance: mutation in DNA polymerase gene
Anti-Cytomegalovirus Agents
Foscarnet
• An inorganic pyrophosphate
• inhibits viral DNA polymerase, RNA polymerase, and HIV
reverse transcriptase
• does not have to be phosphorylated
• Uses: HSV, VZV, CMV, EBV, HHV-6, HBV, and HIV
• Resistance due to mutations in DNA polymerase gene
• Side Effects: hypo- or hypercalcemia and phosphotemia
Anti-Cytomegalovirus Agents
Fomivirsen
• An oligonucleotide
• M.O.A.: binds to mRNA and inhibits protein synthesis
and viral replication
• Uses: CMV retinitis
• Side effects: iritis and increased intraocular pressure
$
%
&
AntiRetroviral Agents
1) Nucleoside Reverse Transcriptase Inhibitors
(NRTIs)
2) Nonnucleoside Reverse Transcriptase
Inhibitors (NNRTIs)
3) Protease inhibitors
'
AntiRetroviral Agents
o Reverse Transcriptase Inhibitors
Zidovudine (AZT)
Didanosine- causes pancreatitis*
Lamivudine- causes pancreatitis
Zalcitabine- causes peripheral neuropathy*
Stavudine- causes peripheral neuropathy*
Abacavir
(
AntiRetroviral Agents
Reverse Transcriptase Inhibitors
Mechanism of Action
Zidovudine (AZT)
• A deoxythymidine analog
• enters the cell via passive diffusion
• must be converted to the triphosphate form by
mammalian thymidine kinase
• competitively inhibits deoxythymidine triphosphate for
the reverse transcriptase enzyme
• causes chain termination
AntiRetroviral Agents
Reverse Transcriptase Inhibitors
Mechanism of Resistance
Zidovudine (AZT)
• Due to mutations in the reverse transcriptase gene
• More frequent after prolong therapy and in persons
with hiv
$
AntiRetroviral Agents
Reverse Transcriptase Inhibitors
Clinical Uses
Zidovudine
• Available in IV and oral formulations
• activity against HIV-1, HIV-2, and human T cell
lymphotropic viruses
• mainly used for treatment of HIV, decreases rate of
progression and prolongs survival
• prevents mother to newborn transmission of HIV
$
AntiRetroviral Agents
Reverse Transcriptase Inhibitors
Side Effects
Zidovudine
• Myelosuppression, including anemia and
neutropenia
• GI intolerance, headaches, and insomnia
$
AntiRetroviral Agents
o Other NRTIs
• Didanosine- synthetic deoxy-adenosine analog; causes
pancreatitis*
• Lamivudine- cytosine analog
• Zalcitabine- cytosine analog; causes peripheral neuropathy*
• Stavudine- thymidine analog;causes peripheral neuropathy*
• Abacavir- guanosine analog; more effective than the other
agents; fatal hypersensitivity reactions can occur
$$
AntiRetroviral Agents
o Nucleotide Inhibitors
• Tenofovir
• Adefovir
$%
AntiRetroviral Agents
Nucleotide Inhibitors
Tenofovir
• An acyclic nucleoside phosphonate analog of
adenosine
• M.O.A.- competively inhibits HIV reverse transcriptase
and causes chain termination after incorporation into
DNA
• Uses – in combination with other antiretrovirals for
HIV-1 suppression
$&
AntiRetroviral Agents
Nucleotide Inhibitors
Adefovir
• An analog of adenosine monophosphate
• Phosphorylated by cellular kinases
• M.O.A. - Competitively inhibits HBV DNA polymerase
and results in chain termination after incorporation into
viral DNA
• Uses - Hepatitis B
• Side effects - nephrotoxicity
$
AntiRetroviral Agents
o Nonnucleoside Reverse Transcriptase
Inhibitors (NNRTIs)
Nevirapine
Delavirdine
Efavirenz
$'
AntiRetroviral Agents
Mechanism of Action
NNRTIs
• Bind to site on viral reverse transcriptase, different from
NRTIs
• results in blockade of RNA and DNA dependent DNA
polymerase activity
• do not compete with nucleoside triphosphates
• do not require phosphorylation
• these drugs can not be given alone
• substrates and inhibitors of CYP3A4
$(
AntiRetroviral Agents
o NNRTIs
• Nevirapine
prevents transmission of HIV from mother to newborn
when given at onset of labor and to the neonate at
delivery
• Delavirdine
teratogenic, therefore can not be given during pregnancy
• Efavirenz
teratogenic, therefore can not be given during pregnancy
$
AntiRetroviral Agents
3. Protease Inhibitors
Indinavir
Ritonavir
Saquinavir
Nelfinavir
Amprenavir
%
AntiRetroviral Agents
o Protease Inhibitors
• The protease enzyme cleaves precursor molecules to
produce mature, infectious virions
• these agents inhibit protease and prevent the spread
of infection
• These agents cause a syndrome of altered body fat
distribution, insulin resistance, and hyperlipidemia
%
AntiRetroviral Agents
Protease Inhibitors
Indinavir and Ritonavir
• M.O.A.: Specific inhibitors of the HIV-1 protease enzyme
• M.O.R.: mediated by expression of multiple and variable
protease amino acid substitutions
• Side Effects:hyperbilirubinemia
• Contraindications:inhibitor/substrate for CPY3A4, do not
give with antifungal azoles
%
AntiRetroviral Agents
Protease Inhibitors
Saquinavir
• A synthetic peptide-like substrate analog
• inhibits HIV-1 protease
• prevents cleavage of viral polyproteins
%$
AntiRetroviral Agents
Protease Inhibitors
Nelfinavir and Amprenavir
• M.O.A.: Specific inhibitors of the HIV-1 protease enzyme
• M.O.R.: mediated by expression of multiple and variable
protease amino acid substitutions
• Less cross-resistance with Amprenavir
• Side Effects: diarrhea and flatulence
• Amprenavir can cause Stevens-Johnson syndrome
• Contraindications:inhibitor/substrate for CPY3A4
%%
AntiRetroviral Agents
Protease Inhibitors
Fusion Inhibitors
• Enfuvirtide (T-20)- binds to the gp41 subunit of the viral
envelope glycoprotein, preventing the conformational
changes required for fusion of the viral and cellular
membranes
• By blocking fusion (entry into cell), FUZEON prevents HIV
from infecting CD4 cells
%&
Nucleoside reverse transcriptase inhibitor (NRTI), non-nucleoside
reverse transcriptase inhibitor (NNRTI) and protease inhibitor (PI)
classes prevent the replication of HIV by working inside CD4 cells after
they have been infected with HIV. The drugs in these three classes then
target specific steps in the replication process to prevent the creation
of new HIV particles.
Fusion inhibitors differ from these drugs because they work on the
outside of the cell to prevent HIV from fusing with, and infecting the
CD4 cells in the first place.
) *+ %
, * -*+
Anti-Hepatitis Agents
Lamivudine -Nucleoside Reverse Transcriptase
Inhibitor (NRTI)
Adefovir -Nucleotide Inhibitor
Interferon Alfa
Pegylated Interferon Alfa
Ribavirin
%'
Anti-Hepatitis Agents
Interferons
Interferon Alfa
• Endogenous proteins
• induce host cell enzymes that inhibit viral RNA
translation and cause degradation of viral mRNA and
tRNA
• Bind to membrane receptors on cell surface
• May also inhibit viral penetration, uncoating, mRNA
synthesis, and translation, and virion assembly and
release
%(
Anti-Hepatitis Agents
Interferons
Pegylated Interferon Alfa
• A linear or branced polyethylene gylcol (PEG) moiety is
attached to covalently to interferon
• Increased half-life and steady drug concentrations
• Less frequent dosing
• Tx chronic hepatitis C in combination with ribavirin
%
Anti-Hepatitis Agents
Ribavirin
• A guanosine analog
• phosphorylated intracellularly by host enzymes
• inhibits capping of viral messenger RNA
• inhibits the viral RNA-dependent RNA polymerase
• inhibits replication of DNA and RNA viruses
&
&
Anti-Influenza Agents
Amantadine
Rimantadine
Zanamivir
Oseltamivir
&
Anti-Influenza Agents
Amantadine and Rimantadine
• Cyclic amines
• Inhibit the uncoating of viral RNA therefore inhibiting
replication
• Resistance due to mutations in the RNA sequence coding
for the structural M2 protein
• Used in the prevention and treatment of influenza A
&$
Anti-Influenza Agents
Zanamivir and Oseltamivir
• Inhibits the enzyme neuraminidase
• inhibit the replication of influenza A and Influenza B
• treats uncomplicated influenza infections
• administered intranasally
&%
&&
&
&'
&(
!"
# #
# !
VIRUSES
• Obligate intracellular parasites
• Consist of a core genome in a protein shell and some
are surrounded by a lipoprotein
• lack a cell wall and cell membrane
• do not carry out metabolic processes
• Replication depends on the host cell machinery
VIRUSES
• Steps for Viral Replication
1) adsorption and penetration into cell
2) uncoating of viral nucleic acid
3) synthesis of regulatory proteins
4) synthesis of RNA or DNA
5) synthesis of structural proteins
6) assembly of viral particles
7) release from host cell
$
ANTIVIRAL AGENTS
• Block viral entry into the cell or must work inside the
cell
• Most agents are pyrimidine or purine nucleoside
analogs
%
SITES OF
DRUG
ACTION
&
Sites of Drug
Action
'
AntiHerpes Agents
•
•
•
•
•
•
Acyclovir - prototype
Valacyclovir
Famciclovir
Penciclovir
Trifluridine
Vidarabine
(
AntiHerpes Agents
Mechanism of Action
Acyclovir
• An acyclic guanosine derivative
• Phosphorylated by viral thymidine kinase
• Di-and tri-phosphorylated by host cellular enzymes
• Inhibits viral DNA synthesis by:
1) competing with dgtp for viral DNA polymerase
2) chain termination
AntiHerpes Agents
Mechanism of Resistance
Acyclovir
• Alteration in viral thymidine kinase
• Alteration in viral DNA polymerase
• Cross-resistance with valacyclovir, famciclovir, and
ganciclovir
AntiHerpes Agents
Clinical Uses
Acyclovir
• Oral, IV, and Topical formulations
• Cleared by glomerular filtration and tubular secretion
• Uses:
– Herpes Simplex Virus 1 and 2 (HSV)
– Varicella-zoster virus (VZV)
• Side Effects: nausea, diarrhea, headache, tremors, and
delirium
$
AntiHerpes Agents
Valacyclovir
• L-valyl ester of acyclovir
• Converted to acyclovir when ingested
• M.O.A.: same as acyclovir
• Uses:
– 1) recurrent genital herpes
– 2) herpes zoster infections
• Side Effects: nausea, diarrhea, and headache
%
AntiHerpes Agents
Famciclovir
• Prodrug of Penciclovir (a guanosine analog)
• M.O.A.: same as acyclovir
• does not cause chain termination
• Uses: HSV-1, HSV-2, VZV, EBV, and hepatitis B
• Side Effects: nausea, diarrhea, and headache
&
AntiHerpes Agents
Trifluridine
• Trifluridine- fluorinated pyrimidine
– Inhibits viral DNA synthesis same as acyclovir
– Incorporates into viral and cellular DNA
– Uses: HSV-1 and HSV-2 (topically)
AntiHerpes Agents
Vidarabine
• An adenosine analog
• inhibits viral DNA polymerase
• incorporated into viral and cellular DNA
• metabolized to hypoxanthine arabinoside
• Side Effects: GI intolerance and myelosuppression
'
Anti-Cytomegalovirus Agents
•
•
•
•
•
Gancyclovir
Valgancyclovir
Cidofovir
Foscarnet
Fomivirsen
(
Anti-Cytomegalovirus Agents
Ganciclovir
• An acyclic guanosine analog
• requires triphosphorylation for activation
• monophosphorylation is catalyzed by a
phosphotransferase in CMV and by thymidine kinase in
HSV cells
• M.O.A.: same as acyclovir
• Uses: CMV*, HSV, VZV,and EBV
• Side Effect: myelosuppression
Anti-Cytomegalovirus Agents
Valgancyclovir
• Monovalyl ester prodrug of gancyclovir
• Metabolized by intestinal and hepatic esterases when
administered orally
• M.O.A.: same as Gancyclovir
• Uses: CMV*
• Side Effect: myelosuppression
Anti-Cytomegalovirus Agents
Cidofovir
• A cytosine analog
• phosphorylation not dependent on viral enzymes
• Uses: CMV*, HSV-1, HSV-2, VZV, EBV, HHV-6,
adenovirus, and human papillomavirus
• Side Effects: nephrotoxicity (prevented by admin. of
probenecid)
• Resistance: mutation in DNA polymerase gene
Anti-Cytomegalovirus Agents
Foscarnet
• An inorganic pyrophosphate
• inhibits viral DNA polymerase, RNA polymerase, and HIV
reverse transcriptase
• does not have to be phosphorylated
• Uses: HSV, VZV, CMV, EBV, HHV-6, HBV, and HIV
• Resistance due to mutations in DNA polymerase gene
• Side Effects: hypo- or hypercalcemia and phosphotemia
Anti-Cytomegalovirus Agents
Fomivirsen
• An oligonucleotide
• M.O.A.: binds to mRNA and inhibits protein synthesis
and viral replication
• Uses: CMV retinitis
• Side effects: iritis and increased intraocular pressure
$
%
&
AntiRetroviral Agents
1) Nucleoside Reverse Transcriptase Inhibitors
(NRTIs)
2) Nonnucleoside Reverse Transcriptase
Inhibitors (NNRTIs)
3) Protease inhibitors
'
AntiRetroviral Agents
o Reverse Transcriptase Inhibitors
Zidovudine (AZT)
Didanosine- causes pancreatitis*
Lamivudine- causes pancreatitis
Zalcitabine- causes peripheral neuropathy*
Stavudine- causes peripheral neuropathy*
Abacavir
(
AntiRetroviral Agents
Reverse Transcriptase Inhibitors
Mechanism of Action
Zidovudine (AZT)
• A deoxythymidine analog
• enters the cell via passive diffusion
• must be converted to the triphosphate form by
mammalian thymidine kinase
• competitively inhibits deoxythymidine triphosphate for
the reverse transcriptase enzyme
• causes chain termination
AntiRetroviral Agents
Reverse Transcriptase Inhibitors
Mechanism of Resistance
Zidovudine (AZT)
• Due to mutations in the reverse transcriptase gene
• More frequent after prolong therapy and in persons
with hiv
$
AntiRetroviral Agents
Reverse Transcriptase Inhibitors
Clinical Uses
Zidovudine
• Available in IV and oral formulations
• activity against HIV-1, HIV-2, and human T cell
lymphotropic viruses
• mainly used for treatment of HIV, decreases rate of
progression and prolongs survival
• prevents mother to newborn transmission of HIV
$
AntiRetroviral Agents
Reverse Transcriptase Inhibitors
Side Effects
Zidovudine
• Myelosuppression, including anemia and
neutropenia
• GI intolerance, headaches, and insomnia
$
AntiRetroviral Agents
o Other NRTIs
• Didanosine- synthetic deoxy-adenosine analog; causes
pancreatitis*
• Lamivudine- cytosine analog
• Zalcitabine- cytosine analog; causes peripheral neuropathy*
• Stavudine- thymidine analog;causes peripheral neuropathy*
• Abacavir- guanosine analog; more effective than the other
agents; fatal hypersensitivity reactions can occur
$$
AntiRetroviral Agents
o Nucleotide Inhibitors
• Tenofovir
• Adefovir
$%
AntiRetroviral Agents
Nucleotide Inhibitors
Tenofovir
• An acyclic nucleoside phosphonate analog of
adenosine
• M.O.A.- competively inhibits HIV reverse transcriptase
and causes chain termination after incorporation into
DNA
• Uses – in combination with other antiretrovirals for
HIV-1 suppression
$&
AntiRetroviral Agents
Nucleotide Inhibitors
Adefovir
• An analog of adenosine monophosphate
• Phosphorylated by cellular kinases
• M.O.A. - Competitively inhibits HBV DNA polymerase
and results in chain termination after incorporation into
viral DNA
• Uses - Hepatitis B
• Side effects - nephrotoxicity
$
AntiRetroviral Agents
o Nonnucleoside Reverse Transcriptase
Inhibitors (NNRTIs)
Nevirapine
Delavirdine
Efavirenz
$'
AntiRetroviral Agents
Mechanism of Action
NNRTIs
• Bind to site on viral reverse transcriptase, different from
NRTIs
• results in blockade of RNA and DNA dependent DNA
polymerase activity
• do not compete with nucleoside triphosphates
• do not require phosphorylation
• these drugs can not be given alone
• substrates and inhibitors of CYP3A4
$(
AntiRetroviral Agents
o NNRTIs
• Nevirapine
prevents transmission of HIV from mother to newborn
when given at onset of labor and to the neonate at
delivery
• Delavirdine
teratogenic, therefore can not be given during pregnancy
• Efavirenz
teratogenic, therefore can not be given during pregnancy
$
AntiRetroviral Agents
3. Protease Inhibitors
Indinavir
Ritonavir
Saquinavir
Nelfinavir
Amprenavir
%
AntiRetroviral Agents
o Protease Inhibitors
• The protease enzyme cleaves precursor molecules to
produce mature, infectious virions
• these agents inhibit protease and prevent the spread
of infection
• These agents cause a syndrome of altered body fat
distribution, insulin resistance, and hyperlipidemia
%
AntiRetroviral Agents
Protease Inhibitors
Indinavir and Ritonavir
• M.O.A.: Specific inhibitors of the HIV-1 protease enzyme
• M.O.R.: mediated by expression of multiple and variable
protease amino acid substitutions
• Side Effects:hyperbilirubinemia
• Contraindications:inhibitor/substrate for CPY3A4, do not
give with antifungal azoles
%
AntiRetroviral Agents
Protease Inhibitors
Saquinavir
• A synthetic peptide-like substrate analog
• inhibits HIV-1 protease
• prevents cleavage of viral polyproteins
%$
AntiRetroviral Agents
Protease Inhibitors
Nelfinavir and Amprenavir
• M.O.A.: Specific inhibitors of the HIV-1 protease enzyme
• M.O.R.: mediated by expression of multiple and variable
protease amino acid substitutions
• Less cross-resistance with Amprenavir
• Side Effects: diarrhea and flatulence
• Amprenavir can cause Stevens-Johnson syndrome
• Contraindications:inhibitor/substrate for CPY3A4
%%
AntiRetroviral Agents
Protease Inhibitors
Fusion Inhibitors
• Enfuvirtide (T-20)- binds to the gp41 subunit of the viral
envelope glycoprotein, preventing the conformational
changes required for fusion of the viral and cellular
membranes
• By blocking fusion (entry into cell), FUZEON prevents HIV
from infecting CD4 cells
%&
Nucleoside reverse transcriptase inhibitor (NRTI), non-nucleoside
reverse transcriptase inhibitor (NNRTI) and protease inhibitor (PI)
classes prevent the replication of HIV by working inside CD4 cells after
they have been infected with HIV. The drugs in these three classes then
target specific steps in the replication process to prevent the creation
of new HIV particles.
Fusion inhibitors differ from these drugs because they work on the
outside of the cell to prevent HIV from fusing with, and infecting the
CD4 cells in the first place.
) *+ %
, * -*+
Anti-Hepatitis Agents
Lamivudine -Nucleoside Reverse Transcriptase
Inhibitor (NRTI)
Adefovir -Nucleotide Inhibitor
Interferon Alfa
Pegylated Interferon Alfa
Ribavirin
%'
Anti-Hepatitis Agents
Interferons
Interferon Alfa
• Endogenous proteins
• induce host cell enzymes that inhibit viral RNA
translation and cause degradation of viral mRNA and
tRNA
• Bind to membrane receptors on cell surface
• May also inhibit viral penetration, uncoating, mRNA
synthesis, and translation, and virion assembly and
release
%(
Anti-Hepatitis Agents
Interferons
Pegylated Interferon Alfa
• A linear or branced polyethylene gylcol (PEG) moiety is
attached to covalently to interferon
• Increased half-life and steady drug concentrations
• Less frequent dosing
• Tx chronic hepatitis C in combination with ribavirin
%
Anti-Hepatitis Agents
Ribavirin
• A guanosine analog
• phosphorylated intracellularly by host enzymes
• inhibits capping of viral messenger RNA
• inhibits the viral RNA-dependent RNA polymerase
• inhibits replication of DNA and RNA viruses
&
&
Anti-Influenza Agents
Amantadine
Rimantadine
Zanamivir
Oseltamivir
&
Anti-Influenza Agents
Amantadine and Rimantadine
• Cyclic amines
• Inhibit the uncoating of viral RNA therefore inhibiting
replication
• Resistance due to mutations in the RNA sequence coding
for the structural M2 protein
• Used in the prevention and treatment of influenza A
&$
Anti-Influenza Agents
Zanamivir and Oseltamivir
• Inhibits the enzyme neuraminidase
• inhibit the replication of influenza A and Influenza B
• treats uncomplicated influenza infections
• administered intranasally
&%
&&
&
&'
&(