Anti-Viral Agents Flashcards
Steps in Viral Replication
Attachment Entry Uncoating Synthesis Assembly Release
Prototype of antiviral agents that are phosphorylated intracellularly by a viral kinase that inhibits viral DNA synthesis
Acyclovir
MOA of Acyclovir
Converted into Acyclovir triphospate to inhibit viral DNA polymerase
Requirement for Acyclovir in its initial phosphorylation
Viral kinases
Compare the bioavailability of acyclovir and valacyclovir
Acyclovir is MORE bioavailable than valacyclovir
Drug used against herpes virus and does not have an effect on CMV
Acyclovir
Adverse effects of Acyclovir
Extrapyramidal signs and renal dysfunction secondary to crystalline nephropathy
Drugs that decrease Acyclovir clearance
Probenicid and Cemetidine
Compare the serum levels of acyclovir and valacyclovir
Valacyclovir > Acyclovir
CSF levels of acyclovir and valacyclovir
50%
Treatment of choice for postherpetic neuralgia used for suppression of frequently recurring genital herpes
Valacyclovir
Adverse effect of Valacyclovir
Seizures at high doses and thrombotic thrombocytopenic purpura
Acyclic guanine nucleoside analog fro Varicella and Genital Herpes
Penciclovir
Main clinical use for Famciclovir
HSV 1 and 2
Compare the triphosphate activity of Acyclovir and Penciclovir
Acyclovir > Penciclovir
Compare the intracellular concentration of Acyclovir and Penciclovir
Acyclovir < Penciclovir
Major difference of Famciclovir and Acyclovir
Famciclovir does not cause chain termination due to the presence of a 3-OH group
Most common side effects of topical drugs
burning sensation, itchiness, erythema
Most common side effects of oral drugs
Nausea, vomiting, diarrhea
Major adverse effects of Peniclovir and Famciclovir
Testicular toxicity on repeated doses but does not change sperms
MOA of Docosanol
Inhibits fusion between plasma membrane and the HSV envelope preventing viral entry
MOA of Trifluridine
Irreversible inhibition of thymidylate synthase and DNA synthesis inhibitor
Clinical significance of Trifluridine
Keratoconjunctivitis secondary to HSV 1 and 2
Anti-viral activity of Ganciclovir
Active against all herpesviruses but especially active against CMV
MOA of Ganciclovir
Inhibits viral DNA polymerase and causes chain termination
Clinical indication for Ganciclovir
CMV retinitis, CMV prophylaxis and CMV colitis
Adverse effect of Ganciclovir
Myelosuppression
Drugs that increase ganciclovir levels
Probenecid and Trimethoprim
Drug that increase in level with ganciclovir when used together
Didanosine
Clinical indication for ganciclovir
CMV retinitis and CMV prophylaxis in organ transplants
Iodinated thymidine analog that inhibits viral DNA synthesis at low concetration
Idoxuridine
Clinical indication of Idoxuridine
Herpes infections of the eyes but not for systemic viral infections
Clinical indication of Foscarnet
CMV retinitis and Acyclovir resistant HSV 2 and VZV in AIDS patient
Adverse effects of Foscarnet
Nephrotoxicity and penile ilcerations
MOA of Cidofovir
Potent inhibitor and alternative of viral DNA polymerase
Cidofovir is cross-resistant with:
Ganciclovir
Two active metabolites of Cidofovir
Cidofovir diphosphate
Cidofovir phosphocholine
It has a longer half-life between the 2 metabolites of cidofovir
Cidofovir phosphocholine
Cidofovir is administered with what drug to block active tubular secretion
Probenecid
Adverse effect of Cidofovir
Nephrotoxicity and Fanconi’s anemia
MOA of Fomivirsen
Inhibits CMV replication through sequence-specific and non-specific mechanisms
Anti-viral activity of Rimantadine and Amantadine
3 antigenic subtypes of influenza A (H1N1, H2N2, H3N2) ONLY
Indication for use of amantadine and rimantadine
Prophylaxis and treatment of Influenza A2
Seizure effects of Amantadine and Rimantadine
Amantadine > Rimantadine
Adverse effects of Amantadine and Rimantadine
CNS toxicity due to Dopamine
MOA of Oseltamivir and Zanamivir
Inhibitor of Influenza A and B nueraminidase
Route of Administration of Oseltamivir and Zanamivir
Oseltamivir is ORAL and Zanamivir is INHALATIONAL
MOA of Adefovir Dipivoxil
Competitive inhibition of DNA polymerase causing chain termination of DNA synthesis