Flashcards in Anti-Viral Drugs Deck (49)
What is the mechanism of action for Acyclovir and related drugs?
Acyclovir acts as a nucleotide analog.
1. It is converted to active drug through 3 phosphorylation steps by viral thymidine kinase; next 2 by host cell enzymes.
2. It is then added to the growing chain of herpes virus DNA, resulting in chain termination.
Which drugs are related to Acyclovir?
What are associated side effects of Acyclovir, et al?
Very few. N/V/D most common.
How are Acyclovir and related drugs administered?
Acyclovir: oral, IV
What enzyme is required for the mechanism of action of Acyclovir?
Viral thymidine kinase
How would you treat cold sores?
Topical Penciclovir. If something stronger is needed, then Acyclovir.
How would you treat HSV Keratitis?
Trifluridine or Idoxuridine
What is the mechanism of action for Trifluridine and Idoxuridine?
Both are analogs of thymidine. Inhibit viral DNA polymerase. Same mechanism as Acyclovir.
How would you treat CMV?
1. Ganciclovir, Valganciclovir, Cidofovir
2. Foscarnet, Fomivirsen
What is the mechanism of action for Ganciclovir, et al?
They act as nucleotide analogs. Because CMV-infected cells lack viral thymidine kinase, phosphorylation occurs by a different kinase.
What is a common side effect of Ganciclovir?
Neutropenia (20-40% of patients)
What are common side effects of Valganciclovir and Cidofovir?
Valganciclovir--similar to ganciclovir
What is the mechanism of action of Foscarnet? What is it used for?
A pyrophosphate that inhibits viral replication at pyrophosphate-binding site on virus-specific DNA polymerases.
Used to treat CMV.
What is the mechanism of action of Fomivirsen?
An oligonucleotide that inhibits CMV replication through anti-sense mechanism.
What is the mechanism of action of Interferons?
Upregulate MHC I expression on hepatocytes; enhance activity of CD8 cells and NK cells.
What is the mechanism of action of PEG Interferon?
1. Attach recombinant IFN-alpha to polyethylene glycol
2. Results in slowed degradation of IFN-->reduces number of weekly doses
What is the role of Type 1 IFN?
1. In uninfected cells: induction of enzymes that block viral replication.
2. In infected cells: increased expression of MHC I; killing by CTLs.
How is Hepatitis B treated?
Peg IFN + NRTI
Drugs used for Hepatitis B and their mechanisms
Lamivudine and Telbivudine --> inhibit HBV reverse transcriptase
Adefovir, Tenofovir, Entecavir --> inhibit reverse transcriptase AND DNA polymerase
What are some side effects of Interferons?
Significant adverse effects due to cascading effect of overproduction of immune cells:
Bone marrow suppression
Depression and other psychiatric disorders
Exacerbation of autoimmune disorders
How is Hepatitis C treated?
PEG-interferon plus Ribavirin plus HCV protease inhibitor (Boceprevir or Telaprevir)
What is the mechanism of action of Ribavirin?
Guanosine analog. Interferes with viral RNA-dependent RNA polymerase.
What are some side effects of Ribavirin?
Dose-dependent hemolytic anemia (10-20% of patients)
What would you use to treat Influenza?
Uncoating inhibitors (A)
Neuraminidase inhibitors (A and B)
Which drugs are uncoating inhibitors? What do they treat?
Treat influenza A.
How does influenza virus leave a cell?
Hemagglutin (HA) is locked in the sialic acid until neuraminidase cleaves the bond, releasing the virus from the cells. Neuraminidase inhibitors would block the virus from leaving the cell.
Which drugs are neuraminidase inhibitors?
How would you treat HPV and genital warts?
1. Alpha interferon injections into wart
What is the mechanism of action of Imiquimod?
Immunomodulatory. Activates immune cells via TLR 7; stimulates IFN alpha and gamma production.