Virology- Drugs Flashcards
For all these drugs I will list the Mechanism of Action, Uses, and any relevant info/precautions.
Acyclovir
A Synthetic analog of guanosine.
Mechanism of Action- Acyclovir monophosphate is phosphorylated (via viral thymidine kinase) to triphosphate. It then integrates into viral DNA and inhibits DNA replication.
Use- Treats HSV-1/2 infections in immunocompromised patients. IV Acyclovir can also treat Varicella Zoster virus.
Info- Oral Acyclovir can be passed through breast milk, topical is not.
Sitavig
An Acyclovir buccal tablet.
Use- Herpes Labialis (Cold Sores) in immunocompetent adults.
VariZIG
Varicella Zoster Immune Globulin
Valacyclovir
L-Valine Ester of Acyclovir
Mechanism of Action- Converted to Acyclovir. Acyclovir monophosphate is phosphorylated to triphosphate, allowing it to integrate into viral DNA to inhibit replication.
Use- HSV-1/2, VZV (Varicella Zoster) in immunoCOMPETENT adults.
Info- Less dosage than Acyclovir, though no IV available. Occurrence of thrombotic thrombocytopenic purpura.
Famciclovir
Mechanism of Action- Phosphorylated by viral thymidine kinase to penciclovir monophosphate. Penciclovir inhibits DNA Polymerase and DNA replication.
Use- HSV 1/2, VZV
Foscarnet
Synthetic Pyrophosphate analog. Directly inhibits viral enzymes without incorporating into viral DNA. Broad spectrum and the drug of choice in Acyclovir and ganciclovir resistance.
Mechanism of Action- Binds to DNA polymerase, preventing it from cleaving pyrophosphate from the newly added deoxynucleoside triphosphate, this halts DNA elongation. Also inhibits the HIV-1 Reverse transcriptase.
Use- HSV-1/2, VZV, CMV, and HIV-1
Info- With Gancyclovir, 1st line of treatment for CMV retinitis in immunocompromised patients. Can cross the Blood Brain Barrier. Treats acyclovir resistant mucocutaneous HSV infections. Highly Nephrotoxic.
Trifluridine/Viroptic
A 1% Opthalmic solution.
Mechanism of Action- A fluorinated pyrimidine nucleoside. Results in nonfunctional viral proteins, but the true mechanism is not known.
Use- Treats keratoconjunctivitis associated with HSV-1/2. Treats Vaccinia virus, CMV, and some strands of Adenovirus.
Info- May result in ocular burning or stinging.
n-docosanol/Abreva
Mechanism of Action- Unclear. Prevents viral entry
Uses- HSV-1/2 and Respiratory Syncytial Virus. Relieves the pain and helps cold sores heal faster.
Info- Shows synergy in combo with other antiviral nucloside analogs (Acyclovir)
Ganciclovir
Synthetic purine nucleoside analog.
Mechanism of Action- Ganciclovir monophosphate is phosphorylated to triphosphate, allowing it to integrate into Viral DNA, which inhibits DNA polymerase, inhibiting viral DNA replication. (It also penetrated non infected cells, however lower concentrations inhibit viral DNA polymerase rather than host DNA polymerase)
Use- CMV (cytomegalovirus), HSV-1/2, Epstein-Barr virus (Mono).
Info- Cannot resolve CMV infection of the CNS, despite penetrating the CNS. Available in oral/IV versions, oral only approved for CMV.
Valganciclovir
L-valine ester (prodrug) of Ganciclovir.
Mechanism of Action- Converted in vivo to Ganciclovir.
Use- Treats CMV retinitis in AIDS patients.
Info- Only oral form available. NOT equivalent to oral Ganciclovir, so they cannot be substituted for each other.
Cidofovir
Synthetic acyclic purine nucleotide.
Mechanism of Action- Inhibits viral DNA synthesis.
Use- CMV infections in AIDS patients.
Info- Only IV form. Probenecid MUST be administered with each dose. Contraindicated for patients with Probenecid or sulfa drug allergies.
Fomivirsen/Vitravene
First Anti-sense drug to be FDA approved.
Mechanism of Action- Single stranded anti sense piece of DNA, complementary to a sequence within the CMV mRNA. Inhibits viral protein synthesis/replication, does not allow the virus to impart resistance.
Use- Intravitreal (into the eye) treatment for CMV retinitis in AIDS patients.
Info- Ocular inflammation may occur.
Imiquimod
Mechanism of Action- Induces cytokines in mononuclear blood cells. Stimulates IL-1, IL-6, IL-8, TNF, and INF-alpha. Affects both the acquired and innate immune mechanisms.
Use- HPV Genital Warts
Info- Topical treatment
Interferon-Alpha
AKA: Roferon-A, Rebetol, Alferon-N, Wellferon
Mechanism of Action- Binds specifically to membrane receptors, setting off a cascade that inhibits viral replication within a cell. Augments macrophage phagocytic activity an lymphocyte cytoxicity.
Use- Hairy cell leukemia, Kaposi’s sarcoma, condyloma acuminata, chronic HBV, chronic HCV infection, melanoma.
Info- Psoriasis and asthma may worsen with treatment.
PEG-INF/Pegasys/Peg-Intron
Mechanism of Action- PEG increases the half life of INF. Results in better efficacy and less serious side effects.
Use- Treating HCV in combination with ribavirin.
Info- Side effects decrease as treatment continues (mainly psychiatric and nausea).
