Viral Pharmacology - Burkin Flashcards
Name the RNA viruses.
- poliovirus
- mumps, measles
- yellow fever
- dengue fever
- rhinovirus
- influenza
- HIV
Name the DNA viruses.
- papilloma
- zoster
- adenovirus
- epstein-barr
- cytomegalovirus
- herpes simplex
Name some ways viral infections are controlled.
- vector control
- immunization
- activation of host resistance
- drugs
What is the drug Amantadine used for?
Prevents spread of influenza A2 and reduces duration of influenza symptoms.
What is the MOA of Amantadine?
- binds to M2 protein of influenza A2 - this protein is responsible for viral uncoating
- may inhibit viral assembly
What are the adverse affects of Amantadine?
- dizziness
- nervousness
- confusion
- hallucinations
- hypotension
- dopamine agonist - releases dopamine
What is Zanamivir and Oseltamivir (Tamiflu) used for?
Early use reduces severity and duration of influenza symptoms.
What is the MOA of Zanamivir and Oseltamivir?
Inhibits replication of influenza A and B. Tamiflu is a prodrug that is hepatically activated.
What are the adverse reactions of Zanamivir and Oseltamivir?
- nausea
- vomiting
- diarrhea
- abdominal pain
- headache
Name the antiviral nucleoside and nucleotide analogs that are purines.
- acyclovir
- adefovir
- gancyclovir
- pencyclovir
- ribavirin
- didanosine/DDI
Name the antiviral nucleoside and nucleotide analogs that are pyramidines.
- azidothymidine
- zalcitabine/ddC
- Stavudine/d4T
- trifluridine
- cidofovir
What is the MOA of Acyclovir?
Inhibits viral DNA polymerase and therefore inhibits viral replication. Acyclovir is a prodrug that is activated by viral thymadine kinase, a viral enzyme.
Name the 3 mechanisms that Acyclovir uses to inhibit viral replication.
- formation of nucleoside analog that DNA polymerase tries to use and can’t so replication stops
- it acts as a competitive inhibitor for DNA polymerase
- it acts as a non-competitive inhibitor by binding to and changing the shape of DNA polymerase
What is Acyclovir used for?
Herpes simplex and varicella-zoster infections.
What are the adverse reactions of Acyclovir?
- oral - headache, veritgo, diarrhea, nausea, vomiting, arthalgia
- IV - local irritation via acidic nature, phlebitis, nephrotoxicity
What is Gancyclovir used to treat?
- herpes simplex
- varicella zoster
- very active against Cytomegalovirus and HCMV retinitis and pneumonia
What is the MOA of Gancyclovir?
A prodrug that is activated by HCMV phosphotransferase. It inhibits DNA polymerase.
What are the adverse reactions of Gancyclovir?
Bone marrow suppression with neutropenia and thrombocytopenia.
What is Ribavirin used to treat?
- broad spectrum
- RSV, influenza
- Hepatitis C, Myxovirus, paromxyovirus
- adenovirus, herpes virus and poxvirus
What is the MOA of Ribavirin?
- Ribavirin monophosphate inhibits guanine nucleoside synthesis
- Ribavirin triphosphate inhibits RNA polymerase
- is a prodrug
What are the adverse side effects of Ribivirin?
- can cause hemolytic anemia in G6PD deficient pt’s
2. can make existing cardiac problems worse
What is AZT used to treat?
Part of antiretroviral therapy used to treat HIV infection.
What is the MOA of AZT?
The triphosphate form preferentially inhibits reverse transcriptase.
What are some other names for AZT?
Zidovudine, Azidothymidine.
What are the clinical effects of AZT?
- increases CD4 counts
- decreases opportunistic infections
- increases survival time
- used in combination therapy -HAART- because resistance high when used in mono therapy
What are the adverse reactions of AZT?
- anemia and granulcytopenia
- headache, nausea, vomiting, myalgia
- myopathy
Name some Dideoxynucleoside class of drugs?
- Didanosine
- Zalcitabine
- Stavudine
These drugs are called the nucleoside reverse transcriptase inhibitors or nRTI’s
What is the MOA of the Dideoxynucleosides?
They are metabolized to competitive inhibitors of reverse transcriptase that cause chain termination.
What are the Dideoxynucleoside drugs used for?
They are used in combination with AZT, protease inhibitors and non-nucleoside reverse transcriptase inhibitors to treat HIV. They are also useful to treat AZT-resistant HIV.
What classes of drugs are included in HAART?
- AZT
- nRTI
- nnRTI
- protease inhbitor
What are nnRTI’s?
This is a class of drugs that are non-nucleoside reverse transcriptase inhibitors. They bind to the hydrophobic region of reverse transcriptase and inhibit it.
Give an example of an nnRTl.
Nevirapine. This drug is relatively well tolerated and is used in combination with nucleoside RTI’s.
What are the adverse reactions of Nevirapine?
- fever, nausea, rash
- hepatitis
- metabolized by cytochrome P450 so has potential drug interactions
Name the Protease inhibitors.
- Ritonavir
- Saquinavir
- Indinavir
- Amprenavir
What is the MOA of protease inhibitors?
They block aspartate preotease that processes proteins that are needed for HIV replication. Thus they also block viral maturation. They do this by mimicking the peptide sequence of viral protein target. Binding blocks the function of the protease.
What are protease inhibitors used to treat?
They are used in combination with AZT and reverse transcriptase inhibitors to treat infection with HIV.
What are the adverse affects of protease inhibitors?
- can cause metabolic syndrome
2. are processed by CYPs and drug reactions may occur
What is Enfuviritide?
This drug is in a class that acts as an antiretroviral fusion inhibitor - they prevent fusion of HIV virus with host cell. It is used in combination with other retroantiviral drugs.
What is the MOA of Enfuviritide?
Mimics components of HIV fusion machinery and binds to gp120 on CD4 T cells and prevents the creation of an entry pore for the virus. It protects healthy CD4 cells from HIV infection.
What are the adverse effects of Enfuviritide?
- injection site reaction
- peripheral neuropathy
- insomnia
- depression
- arthralgia
- hypersensitivity in very small number of pt’s
