Pharm of HIV/AIDS Flashcards
What does ART typically being with as the backbone of therapy?
2 NRTIs (Nucleoside Reverse Transcriptase Inhibitors)
How do NRTIs provide substrate for the enzymes?
Must enter the cell and become phosphorylated
NRTI exert their effects by?
Inhibiting incorporation of native nucleotides and by terminating elongation of proviral DNA
What do NRTIs selective toxicity depend on?
Ability to inhibit HIV reverse transcriptase without inhibiting host cell DNA polymerase
Which human DNA polymerase is inhibited by some NRTI?
The human mitochondrial DNA polymerase (γ)
Which NRTI have the lowest affinity for DNA polymerase γ?
1) Emtricitabine
2) Lamivudine
3) Abacavir
4) Tenofovir
Which nucleotide does the NRTI zidovudine (AZT) and stavudine (d4T) compete with?
Which does emtricitabine and Lamivudine compete with?
Which does abacavir compete with?
Which does tenofovir compete with?
1) Thymidine
2) Cytidine
3) Guanosine
4) Adenosine
What mitochondrial toxicities can NRTIs cause?
1) Lactic acidosis syndrome
2) Peripheral neuropathy
3) Pancreatitis
Which NRTI is the most potent in active cells since thymidine kinase is an S Phase specific enzyme?
Zidovudine
What are the clinical applications of zidovudine besides inhibiting HIV-1 and HIV-2?
Inhibits HTLV-1 and HTLV-2
What NRTI similarly interferes with thymidine incorporation like AZT but is rarely used now because of its toxicities?
Stavudine
What are potential toxicities of stavudine?
1) Peripheral neuropathy
2) Lipodystrophy/fat wasting
3) Lactic acidosis
Bone marrow suppression, skeletal muscle myopathy, and hepatic steatosis are all potential toxicities of?
Zidovudine
The NRTI with the most common serious toxicity of peripheral neuropathy along with being the most strongly associated with lipodystrophy/fat wasting is?
Stavudine
Which NRTIs MOA is to interfere with cytosine incorporation?
Emtricitabine (FTC) and Lamivudine (3TC)
Both emtricitabine and lamivudine have a low barrier to resistance if?
Besides HIV what are they also active against?
They are co-formulated with what other drug?
How are their half-lives compared to other NRTIs?
1) Used in monotherapy
2) HBV
3) Tenofovir
4) Long
What are potential toxicities of emtricitabine and lamivudine?
They are one of the least toxic ART agents but prolonged use of emtricitabine could lead to hyperpigmentation of palms and soles
What NRTI is the only guanosine analog?
Abacavir (ABC)
Abacavir should not be given to patients with what genotype due to a potentially fatal hypersensitivity syndrome?
Also, it is not effective against what virus?
1) HLA-B*5701
2) HBV
Which NRTIs are analogs to adenosine?
1) Tenofovir disoproxil fumarate (TDF)
2) Tenofovir alafenamide (TAF)
How do the tenofovir drugs differ from other NRTIs?
They are nucleotide-RTI not nucleoside-RTI
What other virus are TDF and TAF approved for?
HBV
Which tenofovir has less renal and bone toxicity because plasma concentrations are lower?
Tenofovir alafenamide
What is the best combination of NRTI therapy?
Emtricitabine and tenofovir
Why aren’t emtricitabine and lamivudine combined?
Why aren’t tenofovir disoproxil fumarate and tenofovir alafenamide combined?
1) Both cysteine analogs
2) Both prodrug formulations of the same active agent
What is now recommended for use in treatment of naïve patients unless the HIV load is high?
lamivudine in combination with dolutegravir