Antiretrovirals Flashcards
Which stage of HIV is contagious?
Stage 1
What happens in the acute HIV infection stage 1?
Days to weeks
Fever, chills, rash, nigh sweats, muscle aches, fatigue, swollen nodes, mouth ulcers
Large amount of HIV present
Antigen/antibody test or nucleic acid test (NAT)
Chronic HIV infection stage 2 is
Asymptomatic/clinical latency
Low level reproduction
Transmission possible
What happens at the end of stage 2
Viral load (amount of HIV in blood) increases
CD4 cell count decreases
When is AIDS diagnosed?
By CD4 cell count <200 or by opportunistic infection
Opportunistic infection characteristics
Less common with effective HIV tx
Candidasis
Pneumonias
Encephalopathy
Kaposi sarcoma
What are the types of HIV?
HIV-1
HIV-2
What are the characteristics of HIV-1?
More fatal
Progressess more rapidly towards AIDS
What are the characteristics of HIV-2?
Uncommon
Less infectious
What are the 6 stages of HIV replication?
- Entry
- Reverse Transcription
- Integration
- Replication
- Assembly
- Budding & maturation
Which drugs effect stage 1 of replication, Entry?
Maraviroc
Enfuvirtide
Fostemsavir
What happens in the Entry stage of replication?
Binds CD4 receptors
Cell membrane fusion
Genetic material & enzyme enter
Stage 2 of HIV replication, reverse transcription involves
Reverse Transcriptase enzyme, which converts HIV RNA to DNA
Which drugs interfere with stage 2 reverse transcription?
Nucleoside reverse transcriptase inhibitors & non-nucleoside RTIs
Stage 3 of HIV replication, Integration involves
Enzyme & integrase inserts HIV DNA into CD4 DNA
Cell now infected for remainder of life
Stage 3 of HIV replication, Integration involves is effected by which medications?
Integrase strand transfer inhibitors
Stage 4 of HIV replication, replication, involves
Host CD4 cell used to create new viral RNA
Can antiretrovirals inhibit stage 4, replication?
NO
Stage 5, Assembly is
New viral proteins & enzymes assemble into immature & non -infectious HIV particle “ bud”
Can antiretrovirals inhibit stage 5, assembly?
NO
Stage 6, budding & maturation is
Virus bud in released from host CD4
Enzyme & protease makes mature infectious viral particle
What drug interferes with stage 6, budding & maturation
Protease inhibitors
What is a CCR5 antagonists drug?
Maraviroc
Characteristics of Maraviroc
Not used for initial tx
May be used for drug resistant virus
Risk for hepatotoxicity & orthostatic HOTN
MOA of Maraviroc
HIV enters via CD4 receptor in conjunction with a co-receptor
Blocks entry of R5 viruses into CD4
Entry inhibitors are classified as _____ or _____
Fusion Inhibitors or Attachment inhibitors
How do fusion inhibitors work & what is the drug?
Prevent viral fusion (glycoprotein binding)
Enfuvirtide
Hoe do attachment inhibitors work?
What is the drug of choice?
prevents attachment & entry ( glycoprotein binding)
Fostemsavir
What is the risk associated with taking Fostemsavir, an Attachment inhibitor?
Nausea
Elevated Liver Enzymes
QTc prolongation
Nucleoside RTIS (Nucleoside Reverse Transcriptase Inhibitors) are often used
As combination drugs
What is the MOA of Nucleoside RTIS (Nucleoside Reverse Transcriptase Inhibitors)?
Metabolized by host enzymes
Active metabolite competitively binds reverse transcriptase
Inhibits DNA chain elongation (viral replication
Nucleoside RTIS (Nucleoside Reverse Transcriptase Inhibitors) are active against
HIV 1 & 2
HBV
What drugs are considered to be Nucleoside RTIS (Nucleoside Reverse Transcriptase Inhibitors)?
Lamivudine
Zidovudine
Abacavir
Tenofovir
With Nucleoside RTIS (Nucleoside Reverse Transcriptase Inhibitors), there is a risk for
Drug-resistance by the virus
What are the adverse effects of Nucleoside RTIS (Nucleoside Reverse Transcriptase Inhibitors)?
Mitochondrial toxicity
Peripheral neuropathy
Pancreatitis
Hepatic steatosis
What is the black box warning of Nucleoside RTIS (Nucleoside Reverse Transcriptase Inhibitors)?
Lactic acidosis syndrome
What are the adverse reactions of Zidovudine (AZT), a Nucleoside RTIS (Nucleoside Reverse Transcriptase Inhibitors)?
N/V
Lactic Acidosis
HA
Zidovudine (AZT), a Nucleoside RTIS (Nucleoside Reverse Transcriptase Inhibitors), can be used
In HIV management in pregnancy
In certain viral mutations
Non-nucleoside RTIs (NNRTIs) are often administered
In combination with NRTIs
Non-nucleoside RTIs (NNRTIs) are used for
Initial therapy & tx switch
What is the MOA of Non-nucleoside RTIs (NNRTIs)?
Prevents HIV-1 reverse transcriptase from adding new nucleotides to the growing DNA chain
Different site of action than NRTIs
Reduced chain elongation & replication
Non-nucleoside RTIs (NNRTIs) are active against
HIV-1
1st generation Non-nucleoside RTIs (NNRTIs) like Efavirenz & nevirapine) are
Highly resistant to mutation
The most commonly used Non-nucleoside RTIs (NNRTIs) are Efavirenz & Rilpivirine. What are their adverse effects?
Neurologic & psychiatric effects
Vivid dreams, confusion, dizziness, “hangover”
Irritability, anxiety, mood change, depression & increased suicidality
QTc prolongation
What are the anesthesia considerations with NRTIs?
No interaction with drugs through CYP-450 system
Metronidazole-risk for peripheral neuropathy
What are anesthesia considerations for NNRTIs?
CYP-450 induction of inhibition depending on drug
Opioids- reduce plasma methadone concentration by 50% (withdrawal risks)
Fentanyl & alfentanil- sub-therapeutic levels (increase dose)
Integrase strand transfer inhibitors (INSTIs) are used as
Preferred 3rd agent with 2 NRTIs/NNRTIs
What is the MOA of Integrase strand transfer inhibitors (INSTIs)?
Prevents b ending of viral complex to host DNA
Target the strand transfer of viral DNA integration
Inhibits activity of integrase (catalyzes integration)
Integrase strand transfer inhibitors (INSTIs) are active against
HIV 1 & 2
What drugs are considered Integrase strand transfer inhibitors (INSTIs)?
Raltegravir
Elvitegravir
Dolutegravir
Risk of taking Integrase strand transfer inhibitors (INSTIs)
Risk of integrase resistance & cross resistance with other failed antiretrovirals
Adverse effects of Integrase strand transfer inhibitors (INSTIs)
Wt gain
Insomnia
Dizziness
Rhabdomyolysis, myopathy & myositis
Depression, suicidal ideation (rare & risk in hx of mental illness)
Protease Inhibitors are used
In combo with dual nucleoside therapy
Initial tx
Preferred for patients failing initial ART
Protease Inhibitors should be administered
With a boosting agent like Ritonavir or Cobicistat
What is the MOA of Protease Inhibitors?
Selective Bonding of viral protease
Competitive inhibition of step needed to mature new virus
Results in production of immature visions (non-infectious)
Protease Inhibitors are active against
HIV 1 & 2
Protease Inhibitors have a
Relatively high genetic “barrier” to resistance
What are the adverse effects of Protease Inhibitors
Insulin resistance/Hyperglycemia/DM
Hyperlipidemia
Hepatotoxicity
PR prolongation
What medications are considered to be Protease Inhibitors
Atazanavir
Darunavir
Lopinavir
Most Protease Inhibitors & Elvitegravir (integrase inhibitor)
Combine with another agent like Ritonavir & Cobicistat, which inhibit CYP 3A4
Boosting increases
Trough plasma drug concentrations, Half life & max plasma concentration, which improves potency
What are the anesthesia considerations for Protease Inhibitors
They inhibit CYP 3A4
Extensive metabolism by CYP 450
Protease Inhibitors and Benzos like Midazolam
Prolongs sedation & is a major respiratory depressant
Protease Inhibitors given with Fentanyl or Alfentanil causes
Respiratory depression
Protease Inhibitors given with Dexamethasone cn
Reduce Protease Inhibitors plasma concentration
Protease Inhibitors given with Amio
Causes CV toxicity risk
Which drugs are preferred to minimize drug interactions with Protease Inhibitors
Etomidate
Remifentanil
Desflurane
Atracurium