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    • ACTION: Inhibits the uncoating stage (part of binding) of Influenza A virus.

      • Binds to M-Protein and blocks the pre-lysosomal uncoating, after attachment has already taken place.

      • Viruses can acquire resistance with extended use.

    • VIRUSES: Inhibits primarily the Influenza A virus, but also has activity against Influenza C, Sendai, Dengue, and Rubella viruses.

      • Parainfluenza 1,2,3, Influenza B, and RSV are resistant

    • SIDE-EFFECTS: In 10% of patients, CNS toxicity, nervousness, difficulty concentrating.

    • CLINICAL: Use is restricted to certain subgroups: in epidemics, at-risk patients, hospitalized patients.


    • ACTION: Inhibits viral transcription, by binding to and inhibiting enzymes involved in nucleic acid metabolism. Specifically inhibits inosine monodehydrogenase, involved in the synthesis of GTP.

    • SIDE-EFFECTS: It is toxic in that it does not discriminate well between host cell and virus. Toxic to liver cells and can cause anemia.

    • VIRUSES: RSV in infants, and Lassa Fever intravenously.


    • ACTION: It is converted by HSV viral Thymidine Kinase into a monophosphate activated form. Host cell then converts monophosphate form into triphosphate form. This form then does two things:

      • Binds and inhibits viral DNA polymerase

      • It is incorporated into viral DNA, where it acts as a chain-terminator.

    • RESISTANCE in HSV is due to mutations in two different viral proteins:

      • Viral Thymidine Kinase, preventing conversion of acyclovir to the triphosphate form.

      • Viral DNA polymerase, such that it doesn't bind the drug.

    • VIRUSES: Specific for HSV infections: HSV-1, HSV-2, VZV, but not CMV or EBV.

      • Resistance can occur, due to mutations in either Thymidine Kinase or viral DNA polymerase.


    • ACTION: Binds to DNA-Polymerase -- cellular or viral, thus bad side effects.

    • VIRUSES: Used to be used for HSV-Encephalitis cases. Now surpassed by Acyclovir.


    • VIRUS: CMV, promising new treatment. Also works on HSV.

      • Up to 80% of HIV patients will relapse if therapy is discontinued. CMV pneumonia does not respond as well as other CMV infections.

    • ACTION: Nucleoside analog of guanosine, similar to Acyclovir.

    • SIDE-EFFECTS: Reversible neutropenia, liver and CNS toxicity.


    • ACTION: Inhibits Reverse Transcriptase.

      • AZT is phosphorylated first by host enzymes.

    • VIRUS: HIV-1

Category: Microbiology Notes



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