HIV Flashcards
Differences b/w HIV 1 & 2?
1: More prevalent and more pathogenic
2: Less pathogenic, resistant to NNRTI’s →(Western Africia)
What are the Cell Surface Receptors for HIV ?
- CD4 receptors
-
Chemokine Receptors
- CCR5-
- dectable over entire course of infection
- Found in majority of sexually transmitted HIV-1 infections
- CXCR4-
- Observed in pts with advanced AIDs
- CCR5-
What is the Seroconversion window for HIV?
- Time of infection to production of antibodies
- average 3-4 weeks but up to 6 months
What HIV tests do we have? What does each one do?
- Rapid (antibody tests)
- Blood or oral fluid sample -can be done at home
- Require confirmation though if test is reactive
- Blood or oral fluid sample -can be done at home
- Combination immunoassay -4th gen. test
- detects HIV-1 and HIV-2 antibodies
- detects HIV-1 protein 24 antigen
- More sensitive in diagnosing early infection
- PCR test
- viral load tests to detect genetic material of HIV
Nucleoside and Nucleotide reverse transcriptase inhibitors (NRTI)→ “Nuke’s”
►What drugs do we have available?
►How do we normally use these drugs?
Generic names end in: ine
→Except: Tenofovir, Abacavir
- Emtricitabine
- Lamivudine
- Can’t combine Emtricitabine & Lamivudine because they’re structurally similar
- Tenofovir Disoproxil Fumarate (TDF)
- Renal/Bone ADE’s -osteomalacia/porosis
- Tenofovir Alafenamide (TAF)
- Better tolerated version of TDF – less in blood = less systemic toxicity
- Co-formulated with emtricitabine in Descovy for HIV & HBV
- Abacavir
- ABC
►How do we normally use these drugs?
→Generally: 2 NRTIs + Second class
- )Describe the HIV Lifecycle ? (5 steps)
- ) How do you prevent the development of HIV resistances to the medications?
- Virus identifies, binds and enters CD4+ cell
- Fuses and transcribes into DNA
- Integrated into nucleus
- Replicates, exits via protease
- Smaller pieces, gets out of cell and can infect new cells
- Must block the virus at 2 different steps to prevent the development of resistance
What combination NTRI products do we have available?
1.)
- Truvada
- Emtricitabine + TDF
- Descovy
- Emtricitabine + TAF
- Epizicom
- Lamivudine + Abacavir
- What is the MOA for NRTI’s ?
- What are the drug class side effects for NRTI’s?
1.)
- Inhibit HIV-1 reverse transcriptase (RT) by competitive inhibition of the enzyme, as well as chain termination
- Prevents replication/integration into the cell
2.)
- Lactic acidosis
- Hepatic steatosis
- Lipodystrophy/lipoatrophy
- accumulation or loss of body fat can be permamnent
►Specific ADE’s for Emtricitabine and Abacavir and TDF and TAF?
►If baseline liver test shows hyperlipidemia consider choosing what drug?
- Emtricitabine
- HA, GI issues, Rash
-
Hyperpigmentaiton of palms or soles of feet
- rare-more popular in african americans
-
Hyperpigmentaiton of palms or soles of feet
- HA, GI issues, Rash
- Abacavir
-
Hypersensitivity rxn (severe)
- Associtaed with HLA B*5701→ if pt. is positive for this allele then don’t give drug, rare but test can be neg and rxn can still occur
- Increased risk of MI***
-
Hypersensitivity rxn (severe)
- TDF
- Decreased bone mineral density- osteomalacia
- Renal impairment- Fanconi syndrome
- abnormal reabsorption of nutrients in kidneys
- PK boosters increase risk of renal and BMD toxicity
- TAF
-
reduced ADE’s
- less renal and BMD issues then TDF
-
reduced ADE’s
►TDF associated with lower lipid levels than TAF
If baseline hyperlipidemia, consider TDF
- What NRTI’s have activity against Hepatitis B virus?
- What dose adjustments do you need to make for NRTI’s?
1.)
- Emtricitabine
- Lamivudine
- TDF
- TAF
2.)
- Most are renally excreted → renal dose adjustements
- Abacavir is excreted through the liver via ADH
- Alcohol drinkers can have INCREASED levels of this drug
- Abacavir is excreted through the liver via ADH
What are the DDI’s with NRTI’s?
- Substrates of P-glycoprotein
- TAF>TDF
- Do not give TAF with: →decrease TAF levels
- Phenytoin, Oxcarbazepine, phenobarbital, rifampin, rifabutin, rifapentine, st. John’s wort
- These are all cyp inducers
- Phenytoin, Oxcarbazepine, phenobarbital, rifampin, rifabutin, rifapentine, st. John’s wort
- What Non-nucleoside reverse transcriptase inhibitors do we have available? (NNRTI)?
- What is their MOA?
- Doravirine
- Rilpivirine
- Efavirenz
2.) MOA: Inhibit reverse transcriptase by directly binding to it
→Non-competitive inhibition of reverse transcriptase
- What combination NNRTI products do we have available?
- What are the side effects of NNRTI’s?
1.)
- Most are single tablet with 3 drug combination
- 1 NNRTI + 2 NRTIs
2.)
- Rash
- Toxic epidermal necrolysis
- Steven-Johnson Syndrome
- Liver Toxicity
What specfic ADR’s do we have for….
Doravirine?
Rilpivirine?
Efavirenz ?
- Doravirine→less than efavirenz and rilpivrine**
- abdominal pain
-
abnormal dreams
- If you dream about dora thats abnormal
- Rilpivirine -CNS side effects mainly
- Depression (less than efavirenz)***
- QTc prolongation
- Rash
- Efavirenz - efavirenZ “Z” as in Zzzz (sleep)⇒strongest ADR’s out of the class
- sleepiness
- insomnia
- Depression
- vivid dreams
- Neural tube defects in 1st trimester
Pharmacokinetics of NNRTI’s
- Absorption/food effects of …
- Rilpivirine?
- Efavirenz?
- Metabolism of all NNRTI’s?
- Absorption/food effects of ?
-
Rilpivirine
- take w/ food
-
Efavirenz
- take w/o food
-
Rilpivirine
- Metabolism
- Liver metabolis CYP 450-34A
- Efavirenz-CYP2B6