3 - Antiviral Medications Flashcards
What are the 3 mechanisms of antivirals?
- Alter uncoating of virus
- Polymerase inhibitors
- Inhibit viral protein synthesis
What are the indications for amantadine (Symmetril) and rimantidine (Flumadine)?
Influenza A
What are the indications for oseltamivir (Tamiflu)?
Influenza A or B
What is the mechanism of oseltamivir (Tamiflu)?
Neuraminidase inhibitor - cleaves the budding viral progeny from its cellular envelope attachment point just prior to release.
Classic Prodrug
What antiviral treats respiratory syncytial virus (RSV)?
ribavirin (Rebetol, Virazole)
What are the side effects of ribavirin (Rebetol, Virazole)?
- mutagenic
- teratogenic
- carcinogenic
What anti-viral is used to treat herpes simplex keratitis (in eye)?
trifluridine (Viroptic)
What is the drug of choice for HSV encephalitis?
acyclovir (Zovirax)
What drug is used to treat primary and recurrent herpes in immunocompromised patients?
acyclovir (Zorivax)
What antiviral is used to treat CMV (and CMV retinitis)?
ganciclovir (Cytovene)
Which antiviral is used to treat recurrent genital herpes?
famciclovir and valacyclovir
famciclovir and valacyclovir are prodrugs that form into what as they pass through the intestine?
penciclovir and acyclovir respectively
What are interferons?
A family of naturally occuring, inducible glycoproteins that interfere with the ability of viruses to infect cells
What are the 3 types of interferons and how are they administered?
- Alpha
- Beta
- Gamma
- Administered - intralesionally, subcutaneously, or IV
Whats the basic mechanism of interferons?
Inhibit viral RNA translation, ultimately leading to the degradation of viral mRNA and tRNA
What are the most common indications for use of interferons?
- Hepatitis B and C
- Mutliple Sclerosis
What are some adverse effects of interferons?
- Flu-like symptoms
- Bone marrow suppression
- Neurotoxicity
- CNS effects
- Severe fatigue
- Severe weight loss
- Autoimmune disorders
- Cardiovascular
- Oral
What often alter the viral replication processes and are often toxic to host cells?
Anti-retrovirals
What is the mechanism for anti-retrovirals?
- Inhibits viral attachment and entry
- Polymerase inhibitor
- Antibodies against viral envelope proteins
What is the first HIV agent that inhibits viral entry into host cells?
enfuvirtide (Fuzeon)
What is the target of anti-retrovirals?
Reverse Transcriptase
When a DNA segment is permanently incorporated into the host cell DNA within a nucleus it is termed?
Integration
What does treatment of HIV infection require?
Combination therapy =
HAART
“Highly Active Anti-Retroviral Therapy”
“cocktails”
What are the side effects of anti-retrovirals?
- Anemia
- Leukopenia and granulocytopenia
- Hepatotoxicity
- Peripheral neuropathy
- Pancreatitis
What is another goal while treating patients with anti-retrovirals?
Prevent opportunistic infections
What is used to treat pneumocystis carinii?
A sulfa drug - oral trimethoprim-sulfamethoxazole (Bactrim)
What is a characteristic of nucleoside reverse transcriptase inhibitors?
Must be biotransformed/bioactivated to work - then they inhibit the viral enzyme reverse transcriptase
Nucleoside reverse transcriptase inhibitors dont work on what kind of cell?
The cells that already contain HIV
What are the common nucleoside reverse transcriptase inhibitors?
- didanosine (Videx)
- zidovudine (Retrovir) - “AZT”
- abacavir (Ziagen)
What drug inhibits HIV synthesis and reduces morbidity/mortality from AIDS and AIDS-related complex?
zidovudine (Retrovir) “AZT”
Do non-nucleoside reverse transcriptase inhibitors require bioactivation?
No! But resistance quickly develops if used alone
What’s so different about the protease inhibitor drugs?
They interfere with the action of HIV-infected cells
What are the common protease inhibitors?
- indinavir (Crixivan)
- nelfinavir (Viracept)
- saquinavir (Invirase)
What kind of drug is tenofovir (Viread)?
A nucleotide reverse transcriptase inhibitor - inhibits viral replication
What kind of drug is raltegravir (Isentress)?
Integrase Inhibitor - inhibits integrase, the enzyme that helps insert the viral cDNA strand from reverse transcriptase into the human genome
If someone has “linear gingiva erythema” what do you suspect?
HIV
