Antiviral medications Flashcards
What is Acyclovir? Mechanism?
Acyclovir - Guanine analogs, nucleoside analogs that prevent viral DNA transcription.
for all herpesviridae except cytomegalovirus which lacks the necessary viral thymidine kinase.
Gangciclovir -
for all herpesviridae
Famciclovir and Valacyclovir -
For herpes zoster
For recurrent genital HSV infections
Ganciclovir and Valganciclovir -
Active against all of them but especially against CMV.
High toxicity, used for CMV infections (CMV pneumonitis, retinitis, esophagitis) in AIDS patients and transplant patients
What are the drugs with the same mechanism as Acyclovir?
What are they used to treat?
Gangciclovir -
for all herpesviridae
Famciclovir and Valacyclovir -
For herpes zoster
For recurrent genital HSV infections
Ganciclovir and Valganciclovir -
Active against all of them but especially against CMV.
High toxicity, used for CMV infections (CMV pneumonitis, retinitis, esophagitis) in AIDS patients and transplant patients
What is Foscarnet?
Pyrophosphate analog
Inhibits DNA polymerase
Also very weakly inhibits reverse transcriptase (not potent enough to use as an anti-retroviral)
Used to treat AIDS patients with:
CMV retinitis
Ganciclovir-resistant Herpesviridae
Cidofovir, mechanism and use?
A cytosine analog
Used to treat CMV infections resistant to ganciclovir and foscarnet
High kidney toxicity.
What drugs are used for CMV retinitis
Cidofovir
Foscarnet
Ganciclovir/valganciclovir
Penciclovir
and
Docosanol
Penciclovir - Guanidine analog, with very mild benefits to treat cold sores topically.
Docosanol - inhibits HSV viral entry to cells. Also very mild benefits.
What is the basis of HIV therapy?
HAART
Highly Active Anti-Retroviral Therapy
The most common is triple drug therapy with two NRTIs, and one NNRTI or Protease Inhibitor
3) Protease inhibtors
CCR5 inhibitors
Entry inhibitors
Integrase inhibitors
What are NRTIs and their use?
What was the first NRTI?
What is the major one used now?
NRTIs. Nucleotide reverse transcriptase inhibitors. Nucleotide analogs that halt elongation of the nucleotide.
1st, Zidovudine.
Current: Lamivudine
Especially use Zidovudine during pregnancy, labor, and for mothers post-partum to prevent transmission to babies.
What are NNTIs?
Use and two examples?
Important fact about them?
NNRTIs. Non-nucleoside reverse transcriptase inhibitors for HIV treatment.
Drugs bind directly to reverse transcriptase and inhibit it non-competitively
Nevirapine was the 1st.
Elfavirenz is preferred one now, but has a high likelyhood of causing CNS symptoms, mostly very strange upsetting dreams and insomnia.
Resistance to these drugs develops very rapdily and extends cross reistance to all the other NNRTIs
What are the Protease Inhibitor drugs?
Use?
Major side effect?
1st one?
Two new ones?
These inhibit HIV protease, preventing cleavage of the initial HIV peptide into gag, env, pol proteins.
Cause metabolic abnormalities:
Dyslipidemia,
Insulin resistance
Lipodystrophy - fat accumulation similar to cushings
Names: “-navirs” HIV is navir cleaved
Saquinavir
Atazanavir
Darunavir
Use and mechanism of Enfuvirtide?
An HIV fusion inhibitor
binds gp41 and prevents HIV from fusing to target cells.
What is the use and mechanism of Maraviroc?
Maraviroc
A CCR5 inhibitor
Binds CCR5 receptor and prevents HIV attachment and T-cell infection.
But it can’t be used late in HIV infections, because the virus begins using CCR4 or CXCR4 instead.
So a Tropism Assay should be performed before this treatment is used to make sure it isn’t pointless.
What are the Integrase inhibitors?
Raltegravir
Blocks HIV enzyme Integrase, from integrating reverse transcribed DNA into the genome.
Relatively new and favored
What are the two major classes of drugs used to treat influenza?
ADAMANTANES
and
NEURAMINIDASE INHIBITORS
Adamantanes are usually NOT effective because there is such widespread resistance.
Neuraminidase inhibitors have little resistance seen.
What are the drugs in the adamantane class?
What is their mechanism?
Amantadine
Rimantadine
M2 proton channel inhibitors, prevent viral uncoating.
