Viral chemotherapy Flashcards
What are these: Poliovirus Mumps, measles Yellow fever Dengue fever Rhinovirus Influenza HIV
RNA viruses
What are these: Papilloma Zoster Adenovirus Epstein-Barr Cytomegalovirus Herpes simplex
DNA viruses
What are the stages of viral replication?
- adsorption, penetration and uncoating
- synthesis of viral components
- assembly and release of virus
What is vector control?
controlling mosquitos or something to control dengue and yellow fever
What is immunological control?
vaccines and gamma globulin
How do you control viral infections by activation of host resistance?
utilize interferon
What are the four ways to control viral infections?
vector control
immunizaation
activation of host resistance
drugs (selective toxicity, timing)
What are the 2 major fundamental problems that need ot be overcome in developing antiviral drugs?
- host’s biochemical machinery is used in replication of the virus. This reduces the opportunities for selective action by drugs that block protein and nucleic acid synthesis.
- clinical signs of viral infection occur after the virus is already replicating and the immune response has been elicited.
There are RNA viruses made up of influenze (balnk,blank, and blank)
A B and C
(blank) can be serotyped based on antibody responses to hemaglglutinin (HA) and neuraminidase (NA) on the outside of the viral particle.
Influenza A
What are the commonly found strains of influenza?
H1, 2, 3
N1 and 2
How many known subtypes are there in influenza?
16 H and 9N
What caused the asiatic (russian) flue?
H2N2
What caused the spanish flu?
H1N1
What caused the Asian flu?
H2N2
What caused the Hong Kong flu?
H3N2
What caused the swine flu?
H1N1
Explain influenza virus replication
- virus binds to cell surface with hemagglutinin
- endocytosis
- endosome
- uncoating
- vRNA
- mRNA
- Protein synthesis
- structural and non structural proteins
- budding
Where does amantadine work?
it inhibits uncoating
Where does zanamivir and oseltamivir work?
Release
How does amantadine work?
Binds to M2 protein of influenza A2 and Inhibits uncoating and viral assembly
(blank) prevent spread of influenze A2 and reduces duration of influenza symptoms.
amantadine
What are the adverse reactions of amantadine?
dizziness, nervousness, confusion, hallucinations, hypotension
CNS: releases dopamine, dopamine agonist
How should you give amantadine?
orally (well absorbed from GI tract)
Amantadine is a synthetic compound that inhibits (blank) of replication. It also acts to prevent uncoating of viral RNA.
Stage 1
When shoud you give amantadine?
for prophylaxis and treatment of the elderly or persons with compromised immune systems during influenza epidemics
What does Zanamivir and Oseltamivir do?
they are neuraminidase inhibitors that inhibit replication of influenza A and B
What does early use of zanamivir and oseltamivir do?
reduces severity and duration of influenza symptoms
What are the adverse reactions to zanamivir and oseltamivir?
nausea, headache, vomiting, diarrhea, abdominal pain
What are the purine antiviral nucleosides and nucleotide analogs?
acylovir adefovir gancyclovir pencyclovir ribavirin didanosine (DDI)
What are the pyrmidine nucleoside and nucleotide analogs?
azidothymidine zalcitabine, ddC stavudine d4T trifluridine cidofovir
How does the herpesvirus replicate.
- attachment
- uncoating
- viral DNA to host cell nucleus
- make mRNA and replicate viral DNA
- proteins
- assembly of viron and budding
What does acyclovir block?
it blocks synthesis of viral DNA in herpesvirus
What does acyclovir, vidarabine, foscarnet, ganciclovir do?
inhibit viral DNA polymerse
Viral thymidine kinase converts the drug to a monophosphate. Host enzymes convert it to the triphosphate (acyclo GTP) which preferentially inhibits viral DNA polymerase. This causes chain termination. What is this?
acyclovir (acycloguanosine)
What is acyclovir effective in treating?
most effective drug in treating herpes simplex types 1 and 2, and varicella zoster infection
How should you take acyclovir?
parenteral and oral formulations
What are the adverse reactions of acyclovir?
IV admin -nephrotoxicity, phlebitis and local irritation
topical-local irritation
oral- causes headache, diarrhea, nausea, vomiting, vertigo, arthlagia.
How does Gancylovir work?
activated by HCMV phosphotransferase and inhibits DNA polymerase
What do you use Gancylovir for?
herpes simplex, varicella-zoster very active agaist HCMV HCMV retinitis (primary use) and pneumonia
What are the adverse reactions of ganciclovir?
high incidence of bone marrow suppression (neutropenia and thrombocytopenia) and CNS effects
What drug does this:
Phosphorylated by host enzymes. Ribavirin monophosphate inhibits inosine 5’ phosphate dehydrogenase resulting in decreased synthesis of guanine nucleotides and ultimately decreased synthesis of RNA and DNA. The triphosphate inhibits RNA polymerase.
Ribavirin
How does Ribavirin work?
phosphorylatd by host enzymes to inhibitio iosine 5 phosphate dehydrogenase which results in decreased synthesis of guanine and thus decreased synthesis of RNA and DNA AND triphosphate inhibits RNA polymerase
What is ribavirin used on?
Respiratory syncytial virus, influenza
Hepatitis C, Myxovirus, paromyxovirus, adenovirus, herpes virus, poxviruses,
If you give ribavarin in an aerosolized form, what will you be treating?
RSV
if you are giving ribavarin orally what will you be treating?
influenza A and B and hep C
Explain HIV replication
- viron binding- CD4, chemokines
- reverse transcriptase (RNA to DNA)
- Integration of viral DNA
- Replication of viral RNA
- protease
- Assembly of virions
- release
How does Zidovudine (Azidothymidine (AZT)) work?
AZT is phosphrylated to triphosphate. This inhibits reverse transcriptase. (somewhat selective)
What do you use Zidovudine (AZT) for?
to treat AIDS.
reduces morbidity and mortality in HIV infected patiens. Increases T4 lymphocyte count
What are the clinical effects of Zidovudine (AZT)?
increases CD4 count
decreased opportunistic infections
increases survival time
combination therapy is more effective than zidovudine alone (HAART-highly active antiretroviral therapy)
What are the adverse reactions of Zidovudine (Azidothymidine, AZT)?
- Bone marrow depression leading to anemia, granulocytopenia (30-40%) or thrombocytopenia
- headache, nausea, vomiting, myalgia
- myopathy
What is resistance to zidovudine (AZT) caused by?
Resistance is a function of stage of infection and duration of treatment
How do dideoxynucleosides work?
they are prodrugs that are metabolized to triphosphates that act as competitive inhibitors of reverse transcriptase that cause chain termination (nRTI).
What are dideoxynucleosides used for?
treating AZT-resistant HIV
What are the three kinds of dideoxynucleosides?
ZALCITABINE (DIDEOXYCYTIDINE),
DIDANOSINE (DIDEOXY¬INOSINE),
STAVUDINE (DIDEOXY¬THYMIDINE)
What is HAART made up of?
AZT, protease inhibitor and nnRTI
What are the adverse effects of nRTI?
Dose-limiting toxicities include peripheral neuropathy and gastro¬intestinal distress,
Extended use has identified limiting toxicities including a rare potentially fatal lactic acidosis.
What are the four protease inhibitors?
NELFINAVIR, RITONAVIR, SAQUINAVIR, INDINAVIR
How do protease inhibitors work?
they inhibit an aspartate protease necessary for cleaving the gag/pol pro-protein of HIV
-blocks viral maturation
Combinations of (blank) with (blank) reduce morbidity in AIDs significantly/ Now part of the standard “highy active antiretrovral therapy “ (HAART)
protease inhibitors
nucleotide analogs
What are the adverse reactions to protease inhibitors?
GI distress, hepatotoxicity, a Cushing’s like syndrome, metabolic syndrome
All PI are processed by CYPs and important (blank) can occur
drug interaxns
What are the three Non-nucleoside reverse transcriptase inhibitors (nnRTIs)?
nevirapine
delaviridine
efavirenz
What is nevirapine?
a drug used in combination with nucleoside RTIs
what is nevirapine metabolized by and why is this important?
Metabolized by Cytochrome P450 – potential drug interactions
what are the adverse reactions of nevirapine?
Relatively well tolerated, causes rashes (16%), fever, nausea, hepatitis
How do nnRTIs work?
inhibit reverse transcriptase by binding to a different site than do the nucleside RTIs. HIV strains resistant to nRTIs remain sensitive to the nnRTIs
What are the adverse reactions to nnRTIs?
rashes, stevens-johnson syndrome
What should you not use nnRTIs with?
RIfampin (because they are metabolize by cytochrome p450)
(blank) inhibits DNA polymerase and reverse transcriptase.
Foscarnet
What do you use foscarnet for?
AIDS, HCMV retinitis in AIDS patient
(blank) prevents fusion of the HIV virus with the host cell.
Enfuviritide (T20)
an antiretroviral fusion inhibitor
How exactly do antiretroviral fusion inhibitors (Enfuviritide) work?
mimick components of HIV fusion machinery. Binds to gp120 on CD4+ cells to prevent the creation of an entry pore for the virus
What protects healthy CD4+ cells from HIV infection?
antiretroviral fusion inhibitor
What should you use antiretroviral fusion inhibitors with?
other antiretrovirals
What are common adverse reactions to antiretroviral fusion inhibitors?
injection site reactions, peripheral neuropathy, insomnia, depression and athralgia. Hypersensitivity can occur (.1-1.1% of patients)
(blank) is used in treatment of kaposis sarcoma, genital warts, herpes zoster in AIDS patients and hep C.
interferon alpha
(blank) block several key steps in viral replication including transcription, translation, protein processing and virus maturation
interferon alpha
(blank) is a fusion inhibitor that is a peptide that binds to gp41 on the viral envelope. Administered by subcutaneous injection. Can trigger hypersensitivity reactions on injection.
Enfuvirtide
(blank) is an antisense oligonucleotide against mRNA coding CMV immediate early protein 2.
Fomivirsen
Where do you put fomivirsen in?
Who do you treat with this?
into the vitreous humor to treat CMV retinitis in AIDS patients
What are some investigational drugs and what do they do?
viral entry inhibitors -> CD4 blockers, chemokine receptor antagonists
Integrase inhibitors
T or F
HAART therapy reduces HIV infection rate
T
What are the three phases of AIDs?
acute phase
clinical latency phase
chronic infections
What are the common opportunistic infections in AIDS patients during the actue phase?
Acute retroviral syndrome fever rash lymphadenopathy pharyngitis
What are the common opportunistic infections in AIDS patients during the clinical latency phase?
Thrush Kaposi sarcoma TB reactivation Herpes zoster Herpes simpex bacterial sinusitis pneumonia pneumocystic carinii pneumonia
What are the common opportunistic infections in AIDS patients during the chronic infection phase?
Systemic fungal infections primary TB crytosporiadisis cerebral tooplasmosis progressive mutlifocal leukencepholapthy peripheral neurpathy cerivcal carcinoma cytomegalovirus disease disseminated mycobacterium avium complex non-hodgkins lymphoma CNS lymphoma AIDS dementia complex
Where do you get a spike in CD4 counts in AIDS?
12 weeks between the acute phase and clinical latency phase
What is the CD4 count in the acute phase?
between 1000 and 500
What is the CD4 count in latency period?
b/w 800 and 200
What is the cd4 count in the chronic period?
200 to none (death)